JPS61195155A - Hollow molded body - Google Patents

Abstract

PURPOSE:To provide a hollow molded body of improved gas barrier characteristic, useful as bottles for carbonated drink, beer, etc., comprising polyester and polyamide containing specific amount of carboxyylic acid unit. CONSTITUTION:The objective hollow molded body can be obtained by feeding into a hollow molding machine a dry blend comprising (A) 100pts.wt. of polyethylene terephthalate (or polyester consisting mainly of the same) with an intrinsic viscosity >=0.57 (pref. 0.6-1.2), produced using, as an ester interchange catalyst, pref. manganese compound, and as a polymerization catalyst, pref. germanium or titanium compound, and (B) 5-100 (pref. 10-60)pts.wt. of polyamide with a relative viscosity 1.4-3.5dl/g containing 20-50 (pref. 35-50)mol% of carboxylic acid (dicarboxylic acid) unit followed by molding.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a hollow molded article with improved gas barrier properties, and more particularly to a hollow molded article made of a blend of polyester and a specific polyamide. In particular, the present invention relates to a hollow molded body useful as a container for carbonated drinks, beer, etc.

[Prior art and its problems]

Polyester and polyethylene terephthalate hollow molded bodies have excellent properties such as hygiene, aroma retention, pressure resistance, and lightness, so they are used for seasonings, carbonated drinks, draft beer, cosmetics, and pharmaceutical containers. It is used extremely widely for various purposes.

However, even with such excellent polyethylene terephthalate hollow molded bodies, there is only one drawback: insufficient gas barrier properties, and in the future, we will expand into fields that require further prevention of carbon dioxide loss and oxygen intrusion. Improvement of this gas barrier property is a problem to be solved in this industry.

[Means for solving problems]

Under these circumstances, the inventor of the present invention has studied a hollow molded article with improved gas barrier properties, and as a result, has arrived at the present invention. That is, the gist of the present invention is to find a way to improve the gas barrier properties while maintaining the excellent properties of polyester hollow molded articles. This can be achieved by finding a suitable blend amount with the polyamide.

Generally polyamides, such as 2-nylon.

6.6 - Nylon and the like have lower gas barrier properties in the dry state than polyesters, such as polyethylene terephthalate.
We found that polyamide has good properties, but is worse than polyethylene terephthalate when the humidity is high, and by blending a specific amount of this polyamide, it is possible to improve gas barrier properties while maintaining the excellent properties of polyester hollow molded products. We have discovered an excellent hollow molded body.

That is, the gist of the present invention is a hollow molded article comprising 100 parts by weight of polyester and 5 to 100 parts by weight of polyamide containing 20 to 50 moles of aromatic dicarboxylic acid units.

The present invention will be explained in detail below.

In the present invention, as the polyester, polyethylene terephthalate and polyester containing this as a main component are used. Dicarboxylic acids such as phthalic acid, in7thalic acid, hexahydrophthalic acid, naphthalene dicarboxylic acid, succinic acid, adipic acid, sebacic acid, trimellitic acid, pyromellitic acid, etc. in an amount of 20 moles of total acid components. It is possible to use polyhydric carboxylic acids such as , or oxybenzoic acids such as p-oxybenzoic acid as the acid component.

In addition, in an amount of 20 mc+t% or less of the total alcohol component,
Glycols such as 1.2-propanediol, 1.3-propanediol, /, l-butanediol, /, 6-hexanediol, neopentyl glycol, diethylene glycol, cyclohexibundimethanol, trimethylolpropane, trimethylolpropane, It is also possible to use polyhydric alcohols such as pentaerythritol.

As a method for producing polyester, a so-called λ step reaction is employed, in which a known transesterification reaction or a direct esterification reaction is performed to obtain a polyester oligomer, followed by a polycondensation reaction. In this case, seven or more known compounds such as calcium compounds, manganese compounds, zinc compounds, and lithium compounds can be used as the transesterification catalyst, but manganese compounds are preferred from the viewpoint of transparency.

Further, a phosphorus compound may be added as a stabilizer after the transesterification reaction or the esterification reaction is substantially completed. As the polymerization catalyst, one or more of known antimony compounds, germanium compounds, titanium compounds, and cobalt compounds can be used, preferably antimony compounds, germanium compounds, and titanium compounds, and more preferably germanium compounds and titanium compounds. is used.

Additionally, additives such as color tone improvers and colorants can be added as necessary during the production of polyester.

The polyester used in the present invention can also be subjected to solid phase polymerization, if necessary. The solid phase polymerization treatment is usually carried out at a temperature of /λO°C to just below the melting point of the polyester for several tens of hours or less, but at temperatures ranging from 110°C to 230°C.
It is preferable that the heating time be within the range of 5 hours or more. The intrinsic viscosity of the polyester used in the present invention is 0.57 or more, preferably 0.57 or more.
It is desirable that it be 1.0-/.

The polyamide used in the present invention together with the polyester is a polyamide obtained from a dicarboxylic acid and a diamine, and in some cases, a polyamide obtained by coexisting a lactam compound, which contains 20 aromatic dicarboxylic dispersed units.
! It is a polyamide containing 0 molar ratio. Examples of such aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, and nuclear alkyl substituted products thereof. Diamine is removed. In some cases, aliphatic lactams such as caprolactam and lauryllactam, and aliphatic dicarboxylic acids such as adipic acid and sebacic acid may be copolymerized in the range of 0 to 20 moles.

These polyamides are generally produced by a melt polymerization method, but similar polyamides can also be produced by interfacial polycondensation using, for example, dicarboxylic acid chloride as the dicarboxylic acid used.

The aromatic dicarboxylic acid unit in the polyamide is 20 to 1% of the total amide bond constituent units, preferably J
It is necessary that the range is j −j Omo1%,
When Om is 01% or less, there is almost no improvement in gas clearing properties. Aromatic dicarboxylic acid units 20%-! O
Although the aforementioned copolymerizations are preferred to achieve mot%, it is also possible to blend an aliphatic polyamide, such as 6-nylon, with the polyester to achieve a substantially 20-j Omot%.

The polyamide used in the present invention has a relative viscosity ηrel of 1
．． μ~3. ! dll f range is preferable.

The blend amount of polyester and polyamide is polyamide! ~ioo heavy parts, preferably 1O-r171t[, more preferably 1O-AO parts by weight.

If the amount of polyamide is less than 5 parts by weight, the effect of the present invention cannot be achieved, and if the amount is more than 100 parts by weight, the tensile strength of the polyamide becomes so large that a hollow molded product cannot be obtained by biaxial stretching under the same conditions as polyester. Hateful.

A common method for manufacturing the blow molded article of the present invention is to tri-blend a predetermined amount of polyester and polyamide and feed it directly to a blow molding machine. The pellets may be pelletized and then fed to a molding machine.

Molding using a blow molding machine can be performed in the same manner as conventional blow molding of polyester. For example, in extrusion blow molding, commonly called direct blow molding, or injection blow molding, in which the parison is blown with compressed gas before it has been sufficiently cooled after injection molding, and in biaxial stretch blow molding, A method of molding a preform, which is a preformed product, by injection molding, and then heating and stretching blow molding to make a biaxially stretched blow container, or a method of molding a pipe-shaped intermediate material by extrusion molding, and then molding one end This method involves welding the bottom of the container to form the bottom of the container, then compressing the other end to form the mouth, and biaxially stretching and blowing this.

As for the biaxial stretching ratio, the preform before biaxial stretching (
It is desirable that the volume ratio of the intermediate (intermediate) and the container after biaxial stretching blowing is at least 3 times, preferably at least 3 times FiS.

〔Example〕

The present invention will be explained in more detail below with reference to Examples.

Note that "parts" in the examples represent "parts by weight", and measurements of the intrinsic viscosity of the polyester, the relative viscosity of the polyamide, the transparency, strength, and oxygen permeation amount of the blow molded body are as follows.

<Intrinsic viscosity of polyester [η]> Value measured at 30°C using a mixed solvent of phenol and tetrachloroethane in a weight ratio of 1:1, with concentration/1/dl.

<Relative viscosity of polyamide ηrθ1> R% concentrated sulfuric acid was used, the concentration was 1t7cit,
The value when measured at.

<Toru E! Type A〉 Haze meter manufactured by Nippon Heavy Industries ■ (NDH-200 model)
The value of Haze (image resolution) measured using . Unit (%) <Tensile strength> Width 6.3! Punch out a dumbbell piece of 1111, and use Toyo Baldwin's Tensilon and chuck.
1+1111. The yield strength and elongation at break were measured under the conditions of tensile speed j OyH/jEilF. (23℃.

tschi relative humidity) <Oxygen permeation amount> Rice 1i MODE [N 0ONTROI, OX manufactured by 8 companies
-Boto/l//true (1000) by TRANloo
The value measured at 20°C as the amount of permeation of Ct,). Unit (C
C/Bottle @day @atm) Example 1 A 20% aqueous solution of hexamethylene diamine 2,2 was added to a mixture of water, O12, isophthalic acid, AAll, and terephthalic acid, and acetic acid, /, and Of were added to the mixture. The mixture was charged into a reaction tank equipped with a stirrer, and the atmosphere was sufficiently purged with nitrogen.Then, the pressure was increased by heating until the system pressure reached /Iki/cd, and after reaching 1rIe97at, the system pressure increased to 1ri4.
The polymerization reaction was started by stirring while releasing the pressure to 7 cd. During that time, the internal temperature rose slowly to 210°C, and after 5 hours, almost no water was distilled out, and the internal temperature rose to 25°C.
0°C was indicated. After releasing the pressure in the system, the pressure in the system finally becomes
After reducing the pressure until it reaches 700wFif, perform pressure return.
The molten polymer was extracted from the bottom of the reaction tank.

The aromatic dicarboxylic acid unit content of the obtained polyamide (polyamide-7) was r Omol %, and the relative viscosity ηre4 was 0.

10 parts by weight of a polyethylene terephthalate resin with an intrinsic viscosity [η] of 0.7≠ was triblended with polyamide. (In addition, in advance, polyethylene terephthalate resin is /1.OC, polyamide-7 is to
The material was dried under vacuum for a day and a night. ) Next, using a 60B type injection molding machine manufactured by Toshiba Machine Co., Ltd., the molding machine was set at
! A threaded preform with a diameter of 1 m and a diameter of 1 m was molded, and then blow molded using a blowing machine with a blowing pressure of Ikf//cd to obtain a container with a capacity of 1 m.

The oxygen permeation rate of this container is 0.04' r cc/Bo
ttles aay -atm, and the R of the body of the container is
Age is 37. The tensile yield strength of the j-1 body was 9/-73.

Examples 2 to 6 and Comparative Examples 1 to 3 Same composition as in Example 1 except that ε-caglolactam was copolymerized and the content of aromatic dicarboxylic acid units relative to all amide bonds was changed. Use polyamides with relative viscosity. Using these polyamides,
A blow molded body was produced in the same manner as in Example 1 using a blend of polyethylene terephthalate resin and polyamide shown in Table C, and the results shown in Table 2 were obtained.

Table-7

Claims (1)

[Claims] (1) Polyamide 5-1 containing 100 parts by weight of polyester and 20-50 mol% of aromatic dicarboxylic acid units
A hollow molded article characterized by comprising 0.00 parts by weight.