SU771126A1 - Polypropylene-based composition - Google Patents

Description

The invention relates to a thermoplastic frost-resistant polypropylene-based composition containing oxidized (secondary) polyethylene as a plasticizer and alkaline sulphate lignin, as a filler introduced to improve the resistance to impact loads of the material at low temperatures. The composition can be used for processing into articles, including as a packaging material by injection molding, extrusion, extrusion and other methods. Polypropylene is not a frost-resistant polymer, which significantly limits its scope, the operation of products from it at low temperatures. Frost-resistant polypropylene-based compositions are known to contain ethylene-propylene rubbers, butyl rubbers, siloxane rubbers, polycyclobutylene, and low-molecular-weight plasticizers as a plasticizer, which are fatty acid esters with a high melting point and low freezing point l. In all these compositions, it can be noted that the introduction of low molecular weight plasticizers significantly increases the frost resistance of the system, the low molecular weight plasticizer has an increased tendency to migrate, which is observed during operation, especially at elevated temperatures, which leads to a deterioration of the physicomechanical properties. The introduction of most plasticizers reduces heat resistance as well as hardness while simultaneously increasing the ability to deform at low temperatures. Known compositions of PP with LDPE and HDPE. Combining polypropylene with high molecular weight additives can significantly change the properties of the material.

la in the right direction. Compositions with primary PE have the best combination of materials and the ability to produce compositions with a lower brittleness temperature and higher resistance to orozostoykost compared with PP, enhanced toughness and physico-mechanical characteristics, as well as ray 7711264

its processability, since the melt index of the mixtures in a wide range of PP and PE ratios is higher than that of the initial polymers l}.

Physico-mechanical properties of the compositions of PP and its mixtures with HDPE are presented in the l-abl. one

Table 1

Melt index (at 230 ° C and 21.2 N), g / 10 min

The study of the composition of PP with 5-2 O.V.% PE showed that the introduction of this polymer contributes to a certain decrease in the surface hardness and heat resistance of the material, but at the same time leads to a decrease in the frost resistance temperature by 10-20 C. Such a small effect of PE on the frost resistance is explained This is obviously limited by the compatibility of these two polymers. Thus, when playing in PP, PE plays the role of a high molecular weight plasticizer of polypropylene, PP and PE belong to thermodynamically incompatible polymers, but at the same time they are operationally compatible. processed into products. Limited compatibility is the reason for their low frost resistance.

Also known are compositions of primary PE with oxidized PE h, which

1.78 2.0 2.05 2.12 2.31

35.0 37.5 36.0 34.5 4O, 0

69.0 64.5 62.6 6O, 2 57.4

120.2 23.0 25.4 26.4 28.3

103 99939089

O-5-15-1O-5

characterized by low physicomechanical indicators.

The closest known is a polymer composition containing polypropylene, alkaline sulphate lignin and a low molecular weight plasticizer, diethyl sebacate 4. The low toughness value at low temperatures limits the range of application of products from this composition, and the migration and bleeding during operation of a low molecular weight plasticizer diethyl sebacate cause a deterioration in the properties of this material.

The aim of the proposal is to increase the strength and performance characteristics under low temperature conditions.

The goal is achieved by

that the polymeric composition based on polypropylene, including alkaline sulS

phage lisnine, in addition, it contains foam polyethylene with a content of gel fraction ZO-4O% and degree of oxidation by saponification number 16-20 mg / / g. mole in the following ratio of components, wt.%:

Polypropylene 75-82

Oxidized polyethylene 16, 5-22.5 Alkaline sulphate lignin 1.5-2.5 As the oxidized PE, use is made of film wastes that have served their time and become obsolete (recycled polyethylene).

An increase in the content of secondary polyethylene in the composition above 22.5% leads to a sharp deterioration in the physical and mechanical characteristics and leads to

Use alkaline sulfate lignin 4, the corresponding VTU - 59

Specifications for alkaline sulfate lignin for the production of rubber goods, tires and plastics

Acidity (in no more than H25O),% 0.3

266

to the stratification system. The content of recycled polyethylene less than 16.5% is insufficient.

The technological process of manufacturing products from the proposed polypropylene-based composition using recycled ethylene oxide and alkaline sulfate lignin consists of the following operations: 1) dry mixing of all the components in a fluid or Henschel type mixer; 2) granulation of the obtained powder composition on a conventional single-screw extruder; 3) obtaining products by injection molding, extrusion, pressing, etc.

Prepare the composition of the composition given in Table. 2

table 2

or VTU - 68 in accordance with the data given in table. 3. Table 3

1.5

0.2

No less

8 Oh, O80,0

No more

1,00,5 VTU-59 to VTU-68 regulates the content in the alkaline sulfate lignin of total hydroxyls of at least 10%, the content of methoxyl groups of at least 12%. The modifying effect of lignin upon its introduction into polypropylene manifests itself in an increase in the strength, hardness, and thermal stability of the material, and also in a significant increase in frost resistance upon the introduction of a plasticizing agent without deterioration.

Properties of recycled polyethylene

Melt flow rate at 2 / 1O min

Tensile yield strength, mn / m

Relative extension , %

Brittleness temperature, С

Bulk density of granules, g / cm,

The bulk density of the sinter, g / cm

Destructive stress, mn / m

The content of the gel fraction,

The degree of oxidation by the number of flakes,

MG / GMOL.

7711268

Continuation of table 3

Not less than GOST 11645-73 0.3

Not less than GOST 11262-76 8.5

Not less than GOST 11262-76 60.0

GOST 11782-71

GOST 11035-64

GOST 11035-64

1O, 0GOST 11262-76

30-40

16-2O physico-mechanical properties due to the stabilization of the structure, consisting in the limited mobility of the linear chains of the base polymer and its supramolecular formations during the course of processing. Use secondary polyethylene corresponding to TU 6-O5-1798-76, in accordance with the data given in table. 4. Table 4

97

The compositions are prepared as follows: all components are fed into a fluid type mixer, which is a conical apparatus with a closing lid, providing high-quality mixing and mixing for 45 minutes.

The resulting mixture is fed into the receiving hopper of the extruder, which provides compaction, plasticization, melting,

homogenization and extrusion through

Hardness, MPa55

Vick heat resistance at 0.5n load

0.45 Not Not

Melt flow rate, g / 10 min0.7 1.0

Claims (4)

Claims of the Invention Composition based on polypropylene, including alkaline sulphate lignin, characterized in that, in order to improve the strength and performance characteristics under conditions of low forming the core of the harnesses, which are cut into pellets 3-5 mm in size. The extrusion is carried out on a Car-Co Pcssc uette extruder with a ratio of length to diameter of the worm L-TE-8 worm at 4 73 K. Samples for testing are prepared on a KuAS C 25/32 injection molding machine at a casting temperature of 4–73 ° K. Properties of the above compositions are summarized in table. five.  Tabli.tsa 5 467-67 53 55 15065-69 94 96 less less 11035-64 O, 4O, 45 O, 45 1.1 1.2 of these temperatures, it additionally contains oxidized polyethylene with a gel-hour content}) of an HF of 40% and an oxidative degree of pollination of 1620 mg / g-mol in the following ratio, components, wt%: 11 Polypropylene 75-82 Oxidized polyethylene 16,5-22,5 Alkaline sulfate lignin 1.5-2.5 Source of information taken into account during the examination 1. D. Ivanyukov, M. Fridman, Polypropylene, M., Himi, 1974, p. . 107-124. 26 12 2. Peyska V. А. Study of operational properties of polymer blends. Author. Diss, for the degree of Candidate. tech. sciences. Moscow, 1972, p. 22 3. Melkumo A. AN, et al. Investigation of secondary golliethleia, Plastics, 1977, p. 23-24. 4. V.E. Tul, E.G. Lyubeshkina. Nova is a frost-resistant modification of polypropylene. Poprolin, Plastics, 1966, N9 1, p. 68-69 (prototype).