JP3912579B2 - Polyester resin composition for calendering - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polyester resin composition for calendering, which is useful for industrial processing sheets and films, which have good roll releasability in calendering of polyester, and particularly excellent sheet take-up properties during calendering.
[0002]
[Prior art]
In general, vinyl chloride sheets (and films) are inexpensive and excellent in processability, and are therefore used in large quantities for various applications. There are extrusion molding and calendering methods for processing this sheet, but the calendering method has better dimensional control of sheet thickness and width than extrusion molding, and is suitable for mass production. It has been adopted. The finished vinyl chloride sheet has sheet properties (transparency, flame retardancy, electrical insulation, durability, hardness controllability, etc.) superior to other resins. However, due to the recent generation of dioxins during the incineration of PVC and the suspicion of environmental hormones in plasticizers, there are active moves to replace them with other resin materials. Among the alternative materials, polyester is one of the leading materials in terms of its physical properties and price, and various studies have been made.
[0003]
However, a major problem in substituting PVC with polyester is application to calendar molding. Conventionally, extrusion molding has been frequently used for polyester resins as a method for producing sheets and films because of their ease of processing. If the polyester resin is to be calendered, the adhesive strength to the roll when it is thermoplasticized is relatively strong and adheres to the roll during processing, making it difficult to mold. Therefore, in order to prevent adhesion to the roll, as proposed in JP-A-11-343353, JP-A-2000-136294, JP-A-2000-186191, JP-A-2000-30951, JP-A-2001-64496, etc. Attempts have been made to add various lubricants such as hydrocarbons such as waxes, higher fatty acids, higher alcohols, fatty acid amides, and esters. Addition of these lubricants makes it possible to take out the product without adhering to the roll. However, as a further problem, a resin sagging occurs due to the weight of the sheet before reaching the cooling roll in the next process, and a sheet with high dimensional accuracy is completed. The characteristic of calendar processing is lost.
[0004]
[Problems to be solved by the invention]
In view of the above circumstances, an object of the present invention is to provide a polyester resin composition for calendering that does not cause resin sagging during calendering.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present inventors have intensively studied and have proposed the following invention. That is, according to the present invention, the storage elastic modulus in the tensile mode at 25 ° C. is 10 ⁷ Pa or more, and the width of the temperature region in which the storage elastic modulus in the tensile mode is from 10 ⁷ Pa to 10 ⁶ Pa is 60. A polyester resin composition for calendering, characterized by having a temperature of not lower than ° C. In particular, it is a polyester resin composition for calendering that satisfies the storage elastic modulus by containing 0.1 to 5 parts of polyisocyanate with respect to 100 parts of polyester. Here, the polyisocyanate is preferably a dimer of tolylene diisocyanate.
[0006]
In the present invention, the storage elastic modulus in the tensile mode is obtained by applying a sheet-like resin to a dynamic viscoelasticity measuring apparatus. The size of the sample sheet is, for example, 15 mm in length (excluding the gripping allowance), 4 mm in width, and about 1 mm in thickness, and the measurement conditions are -20 ° C. at a heating rate of 20 ° C./min with the frequency fixed at 10 Hz. Until the measurement becomes impossible (maximum 250 ° C.). The method for preparing the sample sheet is not particularly specified, but the polyester resin is pressed between a heat-resistant film such as a polyimide film by a heat press set at a temperature 10 ° C. or higher than the softening point of the polyester resin, and smooth. A sheet can be obtained.
[0007]
In the present invention, the tensile mode storage modulus of the polyester, at 25 ° C. in 10 ⁷ Pa or higher, and may become 10 ⁷ Pa or less at a temperature lower than 180 ° C. is essential. Furthermore, the width of the temperature region showing from 10 ⁷ Pa to 10 ⁶ Pa in the region of 250 ° C. or lower is 60 ° C. or higher. If it is less than 10 ⁷ Pa at 25 ° C., it is unsuitable for use as a substitute for the PVC sheet intended by this patent. Further, by having the temperature region having a width of 60 ° C. or more, it is possible to maintain viscoelasticity suitable for the temperature control fluctuation and distribution of the calendar during calendering.
[0008]
In the present invention, in order to obtain a polyester having the temperature range of 60 ° C. or higher, it is preferable to blend a polyisocyanate so as to be compatible with polyesters of various compositions to bring about an appropriate chain extension and a crosslinked part. . Although depending on the hydroxyl value of the polyester, it is possible to obtain stable viscoelasticity during calendering by containing 0.1 to 5 parts of polyisocyanate with respect to 100 parts of polyester. The compounding method of polyisocyanate may be previously reacted in an extruder, or may be directly supplied to the calender roll together with the polyester. The polyisocyanate used is not particularly limited to liquids / solids, aromatics / alicyclics / aliphatics, monomers / dimers / trimers / adducts to alcohols, etc., but easy mixing and speed of reaction. Therefore, a dimer of tolylene diisocyanate is preferable.
[0009]
Examples of the dicarboxylic acid of the polyester of the present invention include terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalic acid, 2,6-naphthalic acid, 4,4′-diphenyldicarboxylic acid, and 2,2′-diphenyldicarboxylic acid. Aromatic dicarboxylic acids such as 4,4′-diphenyl ether dicarboxylic acid, adipic acid, azelaic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4 -Aliphatic or alicyclic dicarboxylic acids such as methyl-1,2-cyclohexanedicarboxylic acid, dimer acid and hydrogenated dimer acid can be used. As the polyvalent carboxylic acid component, trimellitic anhydride, pyromellitic anhydride, or the like can be used.
[0010]
Examples of the glycol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, and 2-methyl-1,3. -Propanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3 -Pentanediol, cyclohexanedimethanol, tricyclodecane dimethanol, neopentyl glycol hydroxypivalate, bisphenol A ethylene oxide adduct and propylene oxide adduct, hydrogenated bisphenol A ethylene oxide adduct and propylene Dioxides such as xide adduct, 1,9-nonanediol, 2-methyloctanediol, 1,10-dodecanediol, 2-butyl-2-ethyl-1,3-propanediol, tricyclodecane dimethanol, Polyhydric alcohols such as methylolpropane.
[0011]
Among the combinations of polyvalent carboxylic acids and polyhydric alcohols described above, terephthalic acid / isophthalic acid / ethylene glycol and terephthalic acid / ethylene glycol are preferred as the preferred compositions that give physical properties, transparency, processability, and low cost similar to those of PVC sheets. / Neopentyl glycol, terephthalic acid / ethylene glycol / cyclohexanedimethanol, terephthalic acid / isophthalic acid / ethylene glycol / 1,4-butanediol.
[0012]
As a method for producing polyester, known methods can be used. For example, the above-mentioned dicarboxylic acid and diol component are esterified at 150 to 250 ° C. and then polycondensed at 230 to 300 ° C. under reduced pressure. The desired polyester can be obtained.
[0013]
In addition to polyester and polyisocyanate, the polyester resin composition for calendar processing of the present invention satisfies the viscoelasticity as well as a lubricant, an antioxidant, a plasticizer, a filler, an ultraviolet absorber, and a light stabilizer. , Pigments, antistatic agents and antibacterial agents can be blended. Examples of lubricants include polyolefin waxes, metal salts of organophosphates, organophosphates, higher fatty acids, higher fatty acid alcohols, higher fatty acid esters, etc., especially releasability from rolls and sheet transparency. In this case, the combined use of a polyolefin wax and a metal salt of an organophosphate is recommended. Moreover, as an antioxidant, for example, a phenol-based, phosphorus-based, or thioether-based antioxidant suppresses thermal oxidative degradation of the polyester resin during calendering. Other examples include talc and mica as fillers, and acrylic oligomers and higher fatty acids as plasticizers.
[0014]
The calendering polyester resin composition of the present invention is prepared by mixing the above components using a known mixing device such as a Henschel mixer, and kneading the mixture with a Banbury mixer, mixing roll, warming roll, etc. To be served.
[0015]
【Example】
In order to describe the present invention in more detail, examples will be given below, but the present invention is not limited to the examples. In addition, the measured value described in the Example is measured by the following method.
[0016]
Storage elastic modulus: A sample of the polyester resin composition was placed on a heat press adjusted to 200 ° C. via a polyimide film (“Kapton” manufactured by Toray DuPont) and held at a pressure of ² N / mm ² for 20 seconds. A sheet sample having a thickness of 1 mm was obtained. This was cut into a length of 15 mm (excluding the grip allowance) and a width of 4 mm, and a sample was set in a dynamic viscoelasticity measuring device “DVA-200” manufactured by IT Measurement Control Co., Ltd., and measured in a tensile mode. The measurement conditions were a scan from -20 ° C. until the measurement became impossible (maximum 250 ° C.) at a heating rate of 20 ° C./min with the frequency fixed at 10 Hz.
[0017]
Production example of polyester (A) 194 parts by weight of dimethyl terephthalate, 102 parts by weight of ethylene glycol, 57 parts by weight of neopentyl glycol, tetrabutyl titanate 0 in a reaction vessel equipped with a stirrer, a thermometer and a condenser for distillation .1 part by weight was added, and a transesterification reaction was performed at 170 to 220 ° C. for 2 hours. After completion of the transesterification reaction, the temperature of the reaction system was raised from 220 ° C. to 255 ° C., while the pressure inside the system was slowly reduced to 5 Torr at 255 ° C. over 60 minutes. Further, a polycondensation reaction was performed at 1 Torr or less for 30 minutes to obtain a sufficient molecular weight, and then the vacuum was broken under a nitrogen atmosphere. The obtained polyester was designated as (A). The final composition of this polyester (A) is that terephthalic acid // ethylene glycol / neopentyl glycol = 100/65/35 (molar ratio) by dissolving the resin in deuterated chloroform and measuring proton nuclear magnetic resonance spectroscopy. It turned out.
[0018]
For 100 parts of polyester (A), 1 part of tridecyl poly (oxyethylene) phosphate zinc salt, 0.5 part of styrene-modified polyethylene wax, 0.4 part of high density oxidized polyethylene wax, tetrakis [methylene-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate] 0.1 part of methane, 2 parts of a dimer of 2,4-tolylene diisocyanate ("Desmodur TT / G" manufactured by Bayer Co., Ltd.) in a beaker The mixture (1) was kneaded on two 6-inch chilled rolls set at 180 ° C. The resin adhering to the chilled roll was occasionally removed with a spatula and mixed, and after mixing for a total of 5 minutes, the roll interval was set to 0.3 mm and the sheet was taken out. The state of sheet take-up at this time was smooth without sagging of the resin. The sheet was transparent and uncolored. On the other hand, when the mixture (2) excluding only the dimer of 2,4-tolylene diisocyanate was processed in the same manner and taken up as a sheet, resin sagging occurred, and a sheet having a uniform thickness was obtained. could not.
[0019]
Samples of the mixtures (1) and (2) previously sampled from chilled rolls were pressed with a polyimide film using a heat press to obtain a sheet having a thickness of about 1 mm. From this sheet, a strip having a length of 20 mm (15 mm excluding the gripping margin) and a width of 4 mm was cut out, and the storage elastic modulus in the tensile mode was measured. As shown in FIG. 1, the storage elastic modulus is 10 ⁷ Pa or more at 25 ° C., but the width of the temperature region where the storage elastic modulus is from 10 ⁷ Pa to 10 ⁶ Pa is 90 ° C. for the mixture (1). In contrast, (2) is 45 ° C., mixture (1) is within the scope of this patent, and mixture (2) is outside the scope of this patent.
[0020]
【The invention's effect】
As described above, the calendering polyester resin composition of the present invention has good roll releasability in calendering, and is particularly excellent in sheet take-up during calendering.
[Brief description of the drawings]
FIG. 1 is a graph showing changes in storage elastic modulus of a mixture (1) and a mixture (2).

Claims (1)

It contains 0.1 to 5 parts of a dimer of tolylene diisocyanate with respect to 100 parts of polyester, and has a storage modulus of 1 × 10 ⁷ Pa or more in a tensile mode at 25 ° C., and a tensile mode A polyester resin composition for calendering, characterized in that the width of the temperature region in which the storage elastic modulus at 1 is 10 × 10 ⁷ Pa to 1 × 10 ⁶ Pa is 60 ° C. or more

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