JPH0344569B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for producing polyesterimide molded articles. More specifically, the present invention relates to a method for manufacturing polyesterimide molded products such as films, sheets, and hollow containers that have excellent gas barrier properties, chemical resistance, transparency, heat resistance, and mechanical strength. Prior Art Polyethylene terephthalate is processed into various containers, films, sheets, etc., and is widely used as a packaging material because of its excellent mechanical performance, chemical resistance, and sanitary properties. In particular, with recent improvements in oriented blow molding technology, they are attracting attention as beverage containers. However, polyethylene terephthalate does not necessarily have sufficient gas barrier properties against oxygen, carbon dioxide, etc., and this point is particularly problematic in food and drink containers. Furthermore, the secondary transition point is relatively low at 70°C, and there is also the problem that high temperature filling of food and drink products is not possible. Purpose of the invention The purpose of the present invention is to provide particularly excellent gas barrier properties,
Another object of the present invention is to provide a method for manufacturing a polyesterimide molded product that has transparency, chemical resistance, heat resistance, mechanical strength, etc. Structure of the invention The purpose of the present invention is to obtain the following formula () A difunctional carboxylic acid mainly including imidodicarboxylic acid or its ester-forming derivative represented by the following formula () HO-R-OH ... () [However, in the formula, R is an aliphatic group having 2 to 12 carbon atoms. group or an alicyclic group having 6 to 12 carbon atoms. ] By reacting the glycol shown by the following formula () [However, in the formula, R represents an aliphatic group having 2 to 12 carbon atoms or an alicyclic group having 6 to 12 carbon atoms. ] This is achieved by a method of forming a polyesterimide mainly composed of repeating units shown in Ru. The polyimide dicarboxylic acid of the above formula () used in the present invention is N,N'-1,6-hexamethylene bistrimeritzimide, which is usually obtained by reacting 2 moles of trimellitic anhydride with hexamethylene diamine. It will be done. In the present invention, as described above, a product using hexamethylene diamine as an amine component is used, and a product using such a diamine component has a secondary transition point compared to a polyesterimide using other diamine components (e.g., ethylene diamine). Since it is within a suitable range, it has the advantage that moldability or processability is good and the polymer has excellent chemical resistance. On the other hand, as the diol component of the above formula (),
An aliphatic group where R in the formula has 2 to 12 carbon atoms such as ethylene, trimethylene, tetramethylene, hexamethylene, octamethylene, decamethylene, dodecamethylene, neopentylene; 1,1-cyclohexanegedimethylene, 1,4- Examples include alicyclic groups having 6 to 12 carbon atoms such as cyclohexane dimethylene. Among these, ethylene, tetramethylene, neopentylene, and cyclohexane dimethylene are preferred. That is, as the diol component (), ethylene glycol, tetramethylene glycol, neopentylene glycol, and cyclohexane dimethylol are preferable. In the method of the present invention, the polyesterimide may be copolymerized with a third component in a small proportion (for example, less than 15 mol%), and the third component includes, for example, terephthalic acid, isophthalic acid, diphenyldicarboxylic acid. , aromatic dicarboxylic acids such as phthalene dicarboxylic acid and diphenoxyethane dicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, oxybenzoic acid, β-hydroxyethoxybenzoic acid, ε-oxycaproic acid, etc. Oxycarboxylic acids such as hydroquinone, methylhydroquinone, butyl hahydroquinone, 2,2-
Bis(4-hydroxyphenyl)propane, 1,
Examples include aromatic group-containing diols such as 1-bis(4-hydroxyphenyl)cyclohexane, bis(β-hydroxyethoxy)benzene, 2,2'-bis(β-hydroxyethoxyphenyl)propane, etc. . Polyesterimide can be produced by a method known as a polyester condensation method. For example, an imidodicarboxylic acid represented by the above formula () and/or an ester-forming derivative thereof, such as a lower alkyl ester or an aryl ester such as methyl ester, ethyl ester, etc., and a diol represented by the above formula () are preferably used. is a catalyst, e.g. a transesterification catalyst,
It can be produced by a method of condensation in the presence of a polycondensation catalyst or the like. As the catalyst, catalysts useful in the production of polyethylene terephthalate are preferably used. The polyesterimide used in the present invention needs to have an intrinsic viscosity of 0.4 or more when measured at 35° C. in a mixed solvent of phenol/tetrachloroethane (60/40 (weight ratio)). If the intrinsic viscosity is less than 0.4, the molded product will not have sufficient mechanical strength, which is not preferable. A more preferable intrinsic viscosity is 0.5 or more.
Therefore, by controlling the polymerization conditions, the intrinsic viscosity can be adjusted.
It is necessary to set it to 0.4 or more, especially 0.5 or more. The polyesterimide of the present invention may contain a small amount of a polyfunctional component such as pentaerythritol, glycerin, trimellitic acid, or pyromellitic acid or a monofunctional component such as benzoic acid within the range where the polymer is substantially linear. It may be polymerized or reacted. The polyesterimide in the present invention is substantially amorphous and has excellent transparency, and also has excellent chemical resistance due to its chemical structure. Moreover, since the secondary transition point is in an appropriate range (around 90 to 100°C), both heat resistance, moldability, and workability are appropriately balanced. Furthermore, the polyesterimide has excellent gas barrier properties against oxygen, nitrogen, carbon dioxide, and the like. In the method of the present invention, the above-mentioned polyesterimide is formed into a molded article such as a film, sheet, hollow body (eg, container, tube, etc.) by melt molding. In the method of the present invention, it is particularly preferable to produce molded articles for packaging purposes. A preferred method for producing the film is to dry the above-mentioned polyesterimide, preferably at a temperature of not less than the melting point (Tm) and not more than 350°C, more preferably
A method in which the polymer is melted at a temperature above Tm and below 330°C, extruded through a film forming die, and then rapidly cooled by contacting with a rotating cooling drum kept at a temperature below the secondary transition point (Tg) of the polymer, or through a circular die. A so-called inflation film forming method, in which the film is rapidly cooled with a cooling gas such as extruded air, is employed. The film thus obtained can be used as is, but it is preferable to stretch it further. Stretching is carried out at a temperature in the range of (Tg-10) to (Tg+50)°C, with an area magnification of at least 2 times, more preferably 5 times or more, especially 8
It is preferable to do this twice or more. The stretching method may be uniaxial or biaxial stretching, and the stretched film is preferably heat treated at a temperature between the stretching temperature and (Tm-10)°C. The polyesterimide used in the present invention has a secondary transition point (Tg) of about 90
Since the temperature is around 100°C, processing such as stretching and heat treatment is easy. The above-mentioned film refers to a film with a thickness of 2 mm or less, but a method for manufacturing thicker sheets is to extrude the molten polymer through a sheet-forming die and inject a gas such as air, as in the case of the above-mentioned film. Preferably, a method of rapidly cooling using a cooling medium such as a liquid such as water or using a cooling rotating drum is preferred. In addition, as a method for forming containers, in addition to the deep drawing method by heating the above-mentioned film or sheet above Tg and applying reduced or pressurized pressure, the in-jection blow method, which is usually used for melt molding of bottles, etc. Blow molding methods such as a blow method and an extrusion blow method are exemplified. In this case, the conditions for melting, cooling, stretching, etc. of the polyesterimide can be the same as those for the film, sheet, etc. described above. As a method for melt-molding the tube, extrusion molding is suitable. In this case, the polymer melting conditions can be the same as those used for producing the film or sheet described above. The molded product produced by the method of the present invention can also have a laminated structure, for example, a laminate of the above-mentioned polyester imide layer and a layer of other resin (for example, polyethylene terephthalate, polyethylene isophthalate, polyamide, polyethylene, polypropylene, etc.). It may be a structured film, sheet, bottle or tube. Effects of the Invention According to the method of the present invention, films, sheets, etc. with excellent gas barrier properties, chemical resistance, transparency, and heat resistance can be produced.
Molded articles such as hollow bodies can be manufactured easily and economically. The resulting molded product has particularly good gas barrier properties and is therefore useful as a food container. Examples Hereinafter, the present invention will be further explained with reference to Examples.
Note that parts in the examples mean parts by weight. Further, the secondary transition point (Tg) and melting point (Tm) were measured using a DSC (differential operating calorimeter) at a heating rate of 20° C./min. Furthermore, gas permeability was measured at 25°C using a Seikaken gas permeability measuring device manufactured by Rika Seiki Kogyo Co., Ltd.
Expressed as gas permeability coefficient. Example 1 and Comparative Example 1 492 parts of N,N'-1,6-hexamethylene bistrimeritzimide dimethyl ester, 130 parts of ethylene glycol, and tetrabutyl titanate
0.01 part was placed in a glass reactor equipped with a rectification column and a stirring device, and heated to 220-240°C in a nitrogen stream to distill methanol out. When the amount of methanol distilled reached 60 parts, the temperature was raised to 280°C and the mixture was heated under normal pressure.
React for 30 minutes, 15 minutes at 10-20 mmHg, and further 45 minutes at 0.5 mmHg, intrinsic viscosity 0.97, secondary transition point (Tg)
A transparent amorphous polymer at 94°C was obtained. This polymer was melted and extruded through a T-die with a width of 15 cm and a thickness of 0.5 mm using a 25 mmφ single-screw extruder at a polymer temperature of 275° C. to obtain a film with a thickness of 150 μm. The gas permeability of this film was measured and the results are shown in Table 1. On the other hand, for comparison, the gas permeability of a stretched polyethylene terephthalate film (thickness: 50 μm) was measured, and the results are also listed in Table 1.

[Table] From the above table, it can be seen that the film produced by the method of the present invention has extremely excellent gas barrier properties. Example 2 N,N'-1,6-hexamethylene bistrimeritzimide diphenyl ester 308 parts, 1,4
- 76 parts of cyclohexanedimethanol and 0.017 parts of tetrabutyl titanate were placed in a reactor equipped with a stirrer and heated at 240°C for 30 minutes in a nitrogen stream, then for approx.
The temperature was raised to 290°C over several minutes, and the reaction was carried out at the same temperature under a weak vacuum of about 15 mmHg for 15 minutes and under a high vacuum of 0.5 mmHg for 30 minutes to obtain a polymer with an intrinsic viscosity of 0.67, a Tg of 96°C, and a Tm of 235°C. This polymer was melt-extruded from a T-die using a 25mmφ extruder (polymer temperature 285℃),
A film with a thickness of 100 μm was obtained. When the gas permeability of this film to oxygen and nitrogen was measured, it was 1.5×10 ^-12 (cc・cm/cm ²・sec・cmHg), respectively.
It was 5.2×0 ^-12 (cc・cm・/cm ²・sec・cmHg).

Claims (1)

[Claims] 1 The following formula () Imidodicarboxylic acid or its ester-forming derivative represented by the following formula () HO-R-OH ... () [wherein R is an aliphatic group having 2 to 12 carbon atoms or an aliphatic group having 6 to 12 carbon atoms] It is an alicyclic group. . ] A polyester characterized by reacting with a glycol represented by the following to form a polyesterimide having an intrinsic viscosity of 0.4 or more and consisting mainly of the following repeating units (), and melt-molding the polyesterimide into a film, sheet, or hollow body. A method for manufacturing gas barrier molded products made of imide. [However, in the formula, R is the same as the above formula ()] 2. The method for producing a gas barrier molded article according to claim 1, wherein the hollow body is a container.