RU2303612C1 - Polymer composition for structural materials - Google Patents

Abstract

FIELD: manufacture of building materials.

SUBSTANCE: invention relates to compositions based on polyethylene terephthalate employed as structural material to which, according to invention, a modifier is added, in particular polyarylatoxymate based on tere- and isophthalic acid dichloroanhydides and phenolketoxyme containing phtalide group depicted by following formula:

, wherein M denotes

. Product is characterized by specific viscosity in tetrachloroethane at 25°C η=0.73-0.80 dL/g (0.05-1 % by weight).

EFFECT: increased heat resistance, improved performance characteristics, extended temperature range for using products obtained from claimed material, and increased electrical strength.

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Description

The invention relates to compositions of polyethylene terephthalate. Polyethylene terephthalate (PET) has a number of unique properties: almost zero permeability to water and organic solvent vapors, to oxygen and nitrogen, high resistance to fats, oils, organic solvents, dilute acids and alkalis, high resistance to light, x-ray and UV rays, low water absorption, biological inertness and the possibility of application in contact with food. In addition, PET has excellent physical and mechanical properties. PET is one of the most promising and versatile thermoplastic polymers. PET and its compositions are widely used as a structural material.

Known polymer compositions of polyethylene terephthalate with phenolic stabilizers [US Pat. U.S. 4330462, IPC S08K 5/36. Keck M.H., Gloth R.E., Tazuma J.J. Stabilized polyester composition The Goodyear Tire and Rubber Co. N 148062; declared 05/12/80; publ. 05/18/82; NPK 524/331. US]; with cinnamic acid salts [Alekseeva G.L., Tamazina V.P., Ozerova A.I., Wolf L.A., Zorina I.A. Thermostabilization of polyethylene terephthalate in the presence of cinnamic acid catalysts. Kursk Polytechnic. institute Kursk. 1985, 19 p., Ill. Bible 6 titles Rus Dep. in ONIIThim Cherkasy, N26-hp 6.1.86]; with zinc diisopropyl dithiophosphate [Dervoed N.A., Rusov V.P., Galakova N.G. Composite materials with enhanced thermal stability based on polyethylene terephthalate. Composition polymer, mater. - properties, production and application, 3 Vses. scientific and technical conf., Moscow, September 14-16. 1987. Thesis. doc. M., 1987, p. 83]; with epoxytriphenol resin and melamine [Autosvid. USSR No. 1776677, С08L 67/02, Militskova E.A., Mikhailova T.V. Thermoplastic molding composition, No. 4770685/05; declared 11/04/89; publ. 11/23/92, BI No. 43].

Closest to the claimed technical essence is the polymer composition of PET with amino derivatives of o-benzoquinone [Autosvid. USSR No. 687090], since the use of the above composition allows for effective stabilization of polyethylene terephthalate to a temperature of 335-365 ° C (608-638 K).

The technical task of the invention:

- increasing heat and heat resistance, thermo-oxidative stability of PET compositions;

- an increase in the temperature of the beginning of through conductivity;

- expansion of the temperature range of processing compositions and the temperature range of operation of products based on PET.

To solve this problem, polyarylate oximetate (PAO-2) based on dichlorohydrides of tere and isophthalic acids and phenol ketoxime containing a phthalide moiety is added to the polyethylene terephthalate as a modifier:

where M =

with a viscosity in tetrachloroethane at 25 ° C (298 K) η _pref = 0,73-0,80 dl / g. The ratio of PET: PAO-2 = (99.0-99.95) :( 1-0.005) (wt.%).

The method is illustrated by the following examples.

Example 1. In a mixture of tetrachloroethane: phenol (3: 1), dissolve a mixture of polyethylene terephthalate TU6-05-1984-85 containing 0.05 wt.% PAO-2 polyarylate oximetate. After brief stirring, the resulting solution is precipitated in isopropyl alcohol, filtered and washed many times with hot distilled water. The resulting polymer compositions are dried in a vacuum oven at a temperature of 70 ° C (343 K).

A polyethylene terephthalate mixture is obtained containing 0.05% PAO-2 polyarylate oximetate.

Example 2-4. The mixture is prepared analogously to example 1, dissolving in a mixture of tetrachloroethane: phenol (3: 1) a mixture of polyethylene terephthalate TU6-05-1984-85 containing 0.1; 0.5; 1 wt.% PAO-2 polyarylate oximetate.

Get polyethylene terephthalate mixtures containing 0.1; 0.5; 1% PAO-2 polyarylate oximetate.

Extruding the prepared mixtures (Example 1-4) at a temperature of 100 ° C, at a screw rotation speed of 50-70 rpm, obtain polyethylene terephthalate compositions containing 0.05; 0.1; 0.5; 1 wt.% PAO-2 polyarylate oximetate.

A comparative assessment of the physicochemical properties as well as the processability of unstabilized and stabilized thermoplastics was carried out using accelerated methods. It is known that the temperature range of processing, the nature of the TG, DTG, DTA curves, the values of the melt flow rate (MFR) and the behavior of polymeric materials in an electric field are the most informative in assessing the operational and thermal properties, as well as the manufacturability of various polymer compositions. All this served as the reason for choosing the indicated research methods for characterizing the compositions we obtained. Thermogravimetric analysis was carried out on a MOM derivatograph (Hungary), the heating rate of the samples was 5 deg / min, the sample was weighed 25 mg, the medium was air and argon. The melt flow rate (MFR - a parameter that determines the choice of method for processing thermoplastics) was determined by the method standardized by GOST 11645-73. The dielectric properties of the obtained compositions were studied by the dielectric loss method. The studies were carried out using an AC bridge with a digital readout of the P-5058 grade at 10 ³ Hz in the temperature range of 20-250 ° C (293-523 K). The error in measuring the dielectric loss tangent was not more than 5%.

The research results show that new polyethylene terephthalate compositions containing PAO-2 as a modifying additive, in terms of their main physicochemical properties (heat and heat resistance, thermo-oxidative stability, end-to-end conductivity onset temperature, processing temperature range and product operating temperature range) exceed similar ones properties of known compositions based on PET in a wide temperature range.

Table 1 presents the data of thermal analysis of technical PET (stabilized with phosphorous acid), PET compositions with amino derivatives of o-benzoquinone (prototype), PET (TU6-05-1984-85) and PET composition (TU6-05-1984-85) with PAO -2.

Table 1. Composition The temperature of the beginning of decomposition, ° C Coke residue,% at 600 ° C Technical PET 280 0 PET + amino derivatives of o-benzoquinone (prototype) 335-365 Not investigated PET (TU6-05-1984-85) 340 0 PET (TU 6-05-1984-85) + PAO-2 358 in air 25.0%, in argon ≈ 40%

Thermal analysis of technical PET indicates that weight loss begins at 280 ° C (553 K). The temperature of the beginning of the decomposition of the compositions of PET - amino derivatives of o-benzoquinone (prototype) lies in the region of 335-365 ° C. Data on the complete destruction and coke residue of the PET compositions in the prototype are missing.

When using polyarylate oximet as a modifying additive, the best results were achieved in the case of a PET composition (TU 6-05-1984-85) with 1% PAO-2. The results of TG of this composition are presented in figures 1 (2) and 2.

Figure 1 (1) of the TG PET curve (TU6-05-1984-85) shows that the mass loss begins at 340 ° C (613 K), the temperature of complete destruction in air is ≈600 ° C (873 K). In the composition of PET (TU 6-05-1984-85) with PAO-2, weight loss begins at 358 ° C (631 K) (Fig. 1 (2)), which is 18 ° C higher, while complete destruction is not observed , the coke residue at 600 ° C (873 K) in air was 25% (in argon ≈ 40%), which indicates a higher heat resistance of the proposed composition.

From the DTA curve (figure 2) it is seen that the melting temperature (T _PL ) of the PET composition (TU 6-05-1984-85) with PAO-2 is 242 ° C, which is 8-13 ° C lower than T _PL PET of various grades (T _pl = 250-265 ° C) [Technical properties of polymeric materials: Uch.-sp. pos. / Kryzhanovsky V.K. and others - SPb., Publishing house "Profession", 2003. - 240 p.]. The decrease in T _PL indicates the expansion of the temperature range of processing the composition into a product. In our case, this interval can be T _max -T _min = (358-242) ° C = 116 ° C. On the DTA (air) curve, the peak of thermal degradation has an excess at 411 ° C (684 K), while the portion of the DTA curve of active thermooxidative processes has two peaks at 468 ° C (741 K) and 504 ° C (777 K), the first of which corresponds to thermo-oxidative degradation, the second, the area of which is much larger, is to the structuring processes that determine the coke residue.

The melt flow rate (MFR) of the PET composition (TU6-05-1984-85) with PAO-2, measured at 260 ° C (533 K) and a load of 5 kg, decreases by 1.6-2.2 times depending on the content PAO-2 compared with unmodified PET (TU6-05-1984-85). Apparently, this is due to an increase in the molar mass of the polymer due to the interaction of PET molecules and PAO-2, which, like polyethylene terephthalate, is a polyester. The melt flow rate values of the same composition, measured under the same conditions after 15 minutes of aging, differ from the initial values by no more than 1.5-2.0%, which indicates good thermal stability of the polymer composition. When re-measuring the MFI of samples of PET compositions with PAO-2, the value increased ≈ by 1%, and after 15-minute re-aging in the channel by 1.5-1.7%, which also indicates good thermal stability of the obtained polymer material.

The results of dielectric studies of the obtained compositions showed that the addition of PAO-2 can improve the dielectric properties of PET. It was found that the prepared compositions have higher temperatures of the beginning of through conductivity. For unstabilized PET it is 150 ° C (423 K), while for PET + PAO-2 compositions it is at least 200 ° C (473 K). Therefore, the temperature range of operation of the products increases by 50 ° C.

Thus, the use of PAO-2 polyarylate oximate, which, like polyethylene terephthalate, is a complex polyester, as a modifying additive in a composition with PET, allows one to increase the mass loss onset temperature to 358 ° C (631 K), increase heat and heat resistance, and thermal oxidative stability, expand the temperature range for the operation of PET products, increase the coke residue in air to 25%, increase the onset temperature of through conductivity to 200 ° C (473 K), and also change the MFI of the compositions to values convenient for processing and.

Claims (1)

A polymer composition for structural materials, including polyethylene terephthalate and a modifier, characterized in that as a modifier it contains polyarylate oximetate (PAO-2) based on dichlorohydrides of tere- and isophthalic acids and phenolketoxime containing a phthalide moiety, formulas

where M =

with a viscosity in tetrachloroethane at 25 ° C η _pref = 0,73-0,80 dl / g at the following component ratio, wt.%: Polyethylene terephthalate 99.0-99.95 PAO-2 0.05-1

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