JP2002121367A - Polyester sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet and a film made of a copolymerized polyester which do not cause volume relaxation even when exposed to an atmosphere of >=40 deg.C before a molding processing. SOLUTION: The sheet and the film made of a copolymerized polyester are manufactured from a resin composition comprising 100 pts.wt. of a copolymerized polyester resin, comprising a polyethylene terephthalate resin composed of acid components mainly composed of tetephthalic acid and an ethylene glycol component 10-90 mole % of which are replaced by 1,4- cyclohexanedimethanol, and, incorporated therewith, 1-15 pts.wt. of a rubber component or a rubbery polymer component, and do not undergo volume relaxation in an atmosphere of at least 40 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copolyester sheet which does not undergo volume relaxation under an atmosphere of 40 ° C. or higher. It is mainly used for blisters, various containers, various packages, and films for cards.

[0002]

2. Description of the Related Art Polyester resins are widely used as materials for packaging products such as food containers and blister packs because of their excellent properties such as transparency, mechanical properties, heat resistance, weather resistance and chemical resistance. It has become. A
-An amorphous polyester sheet called PET is noted for its excellent recyclability, low pollution and food safety, and its use is rapidly increasing in recent years as a packaging material replacing vinyl chloride and polystyrene. However, when the amorphous polyester resin sheet is exposed to an atmosphere of 40 ° C. or more, the elongation becomes zero (volume relaxation), and cracks and cracks are easily caused during bending and punching. And cause a decrease in yield. In order to remedy the above-mentioned problems, temperature control during transportation and processing, preheating of the sheet before molding, and the like are required, and this is a factor that increases costs.

[0003]

SUMMARY OF THE INVENTION The present invention is directed to a copolyester sheet which solves the above-mentioned problems and does not cause volume relaxation even when exposed to an atmosphere of 40 ° C. or more before processing.

[0004]

Means for Solving the Problems As a result of intensive search for solving the above problems, the present inventors have found that 1 to 15 parts by weight of a rubber component or rubbery polymer component is blended with polyethylene terephthalate resin. As a result, it has been found that a copolyester sheet and film which do not cause volume relaxation even when exposed to an atmosphere of 40 ° C. or more can be produced. That is, the present invention relates to a copolymerized polyester resin 10 in which the main acid component of the polyethylene terephthalate resin is terephthalic acid, and 10 to 90 mol% of the ethylene glycol component is substituted with 1,4-cyclohexanedimethanol.
The rubber component or the rubbery polymer component is 1 to 0 parts by weight.
The present invention relates to a copolymerized polyester sheet and film made of a resin composition characterized by being blended in 15 parts by weight and not causing volume relaxation under an atmosphere of 40 ° C. or more, and a molded article selected by molding the same. .

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The polyethylene terephthalate resin used in the present invention comprises a dicarboxylic component mainly composed of terephthalic acid, ethylene glycol and 1,4-cyclohexanedimethanol, and 1,4-cyclohexanedimethanol contains 10%. It is a copolymerized polyester obtained by polycondensing a diol component of about 90 mol%. A copolymer polyester resin obtained by substituting 10 to 90 mol% of an ethylene glycol component with 1,4-cyclohexanedimethanol is used.
When the substitution amount of the ethylene glycol component is less than 10 mol% or more than 90%, the crystallinity of the resin is increased, and the heat sealability is reduced, and the transparency of the sheet is reduced.
Therefore, the amount of substitution of the ethylene glycol component with 1,4-cyclohexanedimethanol is preferably 10 to 90 mol%, and more preferably 20 to 35 mol%. Acid components other than terephthalic acid include, for example, dimethyl terephthalic acid,
Isophthalic acid, phthalic acid, succinic acid, glutaric acid, adipic acid, β-methyladipic acid, pimelic acid, 1,6-
Hexanedicarboxylic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, hexadecanedicarboxylic acid and the like can be mentioned, and a small amount can be mixed.

In the present invention, a function of preventing volume relaxation is imparted by incorporating a rubber component. The rubber components include butadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene-styrene, isobutylene-
Isoprene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, acrylonitrile-butadiene rubber, styrene-butadiene-styrene rubber, hydrogenated styrene-butadiene rubber, styrene-isoprene-styrene rubber, hydrogenated styrene-isoprene rubber, etc. Can be mentioned. Further, a rubber-like elastic body containing a rubber-like polymer component may be blended. An example of the rubber-like elastic body is a copolymer obtained by polymerizing one or more vinyl monomers in the presence of a rubber-like polymer. Examples of the rubbery polymer include acrylic polymers and methacrylic polymers mainly containing alkyl acrylates and alkyl methacrylates, diene polymers mainly containing conjugated dienes such as butadiene and isoprene, and silicones mainly containing polyorganosiloxane. One or two or more copolymers of the series polymer can be exemplified. Examples of the vinyl monomer include aromatic vinyl compounds such as styrene and α-methylstyrene, (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate, and cyanates such as acrylonitrile. And vinyl chloride compounds. Such rubber-like elastic bodies include methyl methacrylate / butyl acrylate / styrene resin (hereinafter abbreviated as MAS resin), methyl methacrylate / butadiene / styrene resin (hereinafter abbreviated as MBS resin), butyl acrylate / isoprene / styrene resin (hereinafter, abbreviated as MBS resin). Hereinafter, these are abbreviated as MAIS resin), and known ones can be used. Particularly, MBS resin is preferable.

These rubber components and rubber-like elastic bodies may be used alone or in combination of two or more.

The amount of the rubber component or the rubbery polymer component to be added is 1 to 15 parts by weight based on 100 parts by weight of the copolymerized polyester. Preferably, it is 2 to 10 parts by weight. If the amount is less than 1 part by weight, the volume relaxation cannot be suppressed, and the elongation decreases, causing an increase in molding failure and a decrease in yield. Fifteen
When the amount is more than the weight part, the heat resistance is deteriorated.
In addition, this leads to an increase in cost, which is not preferable.

The copolymerized polyester resin sheet of the present invention may contain, if desired, commonly used additives such as stabilizers, lubricants, processing aids, antistatic agents, antioxidants, neutralizing agents, ultraviolet absorbers, A dispersant, a thickener, a flame retardant, other inorganic fillers, and the like, or other synthetic resins can be contained as long as the mechanical properties are not significantly reduced.

In order to process the resin composition of the present invention into a sheet, conventionally, a calendering method, an extrusion method, a pressing method,
There is a casting method, etc., but there is no particular limitation here. Further, there is no problem even if a part of the multilayer sheet component is formed into a sheet by a coextrusion method. Further, in the present invention, a molded article such as a food packaging container can be obtained by molding the film and sheet of the present invention.

[0011]

EXAMPLES The present invention will be described below by way of examples, which are merely examples, and the present invention is not limited to these examples. << Preparation of Compound >> As the copolymerized polyester resin composition of the present invention, a compound was prepared from the composition shown in Table 1 using a twin-screw extruder. The symbols in the table are as follows. (1) PETG resin-1: a copolymerized polyester resin obtained by substituting 30 mol% of an ethylene glycol component in a polyethylene terephthalate resin with 1,4-cyclohexanedimethanol. (Tg = 69 ° C.) (2) PETG resin-2: 5 mol% of ethylene glycol component in polyethylene terephthalate resin was
Copolyester resin substituted with 4-cyclohexanedimethanol. (Tg = 85 ° C.) (3) PETG resin-3: A copolymerized polyester resin in which 95 mol% of an ethylene glycol component in a polyethylene terephthalate resin is substituted with 1,4-cyclohexanedimethanol. (Tg = 88 ° C.) (4) MBS resin-1: B-56 (manufactured by Kanegafuchi Chemical) (rubber component: 65%) << Preparation of Sheet >> The copolyester resin sheet of the present invention uses a T-die for extrusion. Used to make a single layer sheet. Table 2 shows the evaluation results of the single-layer sheet. << Examples and Comparative Examples >> The prepared single-layer sheets were stored in high-temperature and high-humidity tanks having different temperatures and humidity, and it was confirmed whether or not volume relaxation (decrease in elongation) occurred. Table 2 shows the results. Various evaluations were performed based on the following. The elongation is J
It measured based on ISK6734. (1) Confirmation of elongation when stored at 23 ° C. and 50%: The prepared single-layer sheet was stored for one day in a place controlled at 23 ° C. and 50%. A sample was punched out with a No. 1 dumbbell before the test measurement, and then a tensile test was performed at a tensile speed of 200 mm / min. (2) Confirmation of elongation when stored at 60 ° C. 50%: The prepared single-layer sheet is stored for one day in a place controlled at 60 ° C. 50%. A sample was punched out with a No. 1 dumbbell before the test measurement, and then a tensile test was performed at a tensile speed of 200 mm / min. (3) Confirmation of elongation when stored at 40 ° C. 90%: The prepared single-layer sheet was stored for one day in a place controlled at 40 ° C. 90%. A sample was punched out with a No. 1 dumbbell before the test measurement, and then a tensile test was performed at a tensile speed of 200 mm / min. (4) Confirmation of elongation during long-term storage at 40 ° C. 90%: The prepared single-layer sheet was stored in a place controlled at 60 ° C. 50% for 3 months. A sample was punched out with a No. 1 dumbbell before the test measurement, and then a tensile test was performed at a tensile speed of 200 mm / min. (5) Heat sealability: 150 ° C. × 2 seconds between sheets,
Bonding was performed at a pressure of 2 kg / cm ² , and the seal strength was measured. 〇: 500g / 15mm or more ×: 500g / 15mm or less

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

According to the polyester resin sheet of the present invention, it is possible to prepare a copolymerized polyester sheet and film which do not cause volume relaxation even when exposed to an atmosphere of 40 ° C. or more.

Claims (2)

[Claims] 1. A polyethylene terephthalate resin in which a main acid component is terephthalic acid and 10 to 90 mol% of an ethylene glycol component is replaced by 1,4-cyclohexanedimethanol, and 100 parts by weight of a copolymerized polyester resin is a rubber. A copolymerized polyester sheet or film made of a resin composition containing 1 to 15 parts by weight of a rubber component or a rubber-like polymer component, and which does not cause volume relaxation in an atmosphere of 40 ° C. or more. 2. A molded article obtained by molding the sheet or film according to claim 1.