CS248085B1 - Additive into polypropylene for lowering the breakage and lowering amount of waste in finishing stretch of polypropylene fibres - Google Patents

Abstract

The purpose of the invention is to reduce breakage and reducing the amount of waste in the polypropylene fibers. The stated purpose is achieved by use as admixtures of a mixture of 0.01 to 3, preferably 0.05 to 0.25% by weight of zinc stearate with 0.01 to 1.5, preferably 0.03 to 0.25% by weight calcium stearate. Yet all the amounts of additives are calculated on a base the final fiber. The invention can be used in the preparation of a processing of polypropylene fibers.

Description

The invention relates to the production of polypropylene stretch fibers. This production generates a large amount of waste, mainly as a result of rupture of polypropylene fibers.

Modification of polypropylene, as well as its blend with pigments and other ingredients, is effective to reduce breakage and reduce the amount of waste when pruning polypropylene fibers. The literature, including the patent, lacks data on waste reduction and number of breaks of polypropylene fibers when adding small amounts of a mixture of zinc and calcium stearates. Meanwhile, small amounts of the abovementioned substances are not used to reduce the number of breaks and the amount of waste of polypropylene and its mixture with the ingredients commonly used in the preparation of fibers and other products.

When using stearates as an additive to reduce tear and reduce the amount of waste in the polypropylene fiber spinning, 0.01 to 3, preferably 0.05 to 0.25% by weight zinc stearate is mixed with 0.01 to 1.5, preferably 0, 03 to 0.25% by weight of calcium stearate with polypropylene. All amounts of additives are calculated on the basis of the final fiber.

The above additives under operating conditions may be added to the polypropylene powder prior to the preparation of the pigment concentrates by mixing these and other ingredients, preferably in a turbulent mixer.

Further, it is possible to prepare separate concentrates either from individual stearates, preferably up to 20%, or from a blend of the two stearates in powdered polypropylene by mixing, preferably in a turbulent mixer and remelting the mixture and then adding it as a granulate. The metering is carried out by means of a volumetric dispenser in the melt-spinning stage, either into the base or secondary melting screw.

Optionally, it is possible to add as a pure additive before granulating the polymeric feedstock. The additive is mixed with the polypropylene and its mixtures in commercial mixing equipment under normal conditions. The mixture obtained is melted in a melter. Here, the melting temperatures of the mixture, the transport and the melt spinning are desirably adjusted so as to obtain a melt index, preferably 1 to 15 g / 10 min higher, compared to the upper limit of the normal production index of the given shade. Then the undiluted fiber is divided. The melt index was determined on a Gotfert plastomer according to standard.

The number of breaks per tonne and hence the scrap nonwoven fiber waste produced is much less when added to polypropylene with small amounts of zinc and calcium stearates compared to polypropylene fiber without added stearates. This effect of small amounts of the above stearate mixture is novel. It is based on the effect of these additions to improve the recovery properties, structural stabilization and synergism in the polymer.

With the above-mentioned additive ratios, they interact with each other, with the polypropylene and possibly also with the other components of the polymer system. This synergistic effect contributes to obtaining a new effect.

An advantage of the above invention appears to be the use of additives in small amounts of accessible, inexpensive and non-toxic substances, such as zinc and calcium stearates.

A further advantage of the above invention is an accessible, simple and economical process using mechanical mixing and melting - conventional processing steps in the preparation of fibers and plastics products. Therefore, for the other advantages mentioned above, the use of the stearates of the invention is technically advantageous.

Example 1

The granulated polypropylene of the trademark Tatren TE 451 at 230 ° C and a 2.16 kg plastomer paste coating had a melt index of 3.89 to 4.78 g / 10 min as well as a pseudoplasticity index of 1.66. Tatren HPF powder polypropylene had a melt index of 35.31 g / 10 min also at 230 ° C and a 2.16 kg load. In the preparation of test mixtures of antistatic substances obligatory used in normal production were not added.

Prepared in a food mixer with mechanical stirring for 20 min, a joint mixture of zinc and calcium stearates into powdered polypropylene Tatren HPF was remelted in a mono-screw granulator "Sikoplast" with a screw diameter of 80 to 125 mm at temperatures:

Zone 240 ° C,

II. zone 230 ° C,

III. 180 ° C zone,

IV. 180% zone

Zone 220 ° C, head 240 ^e C, oil heating 220 ° C, degassing 170 ° C.

The formed strings of the mixture after water and air-blowing cooling were cut into granules on a cutting device. The thus-blended mixture with a melt index of 21.24 g / 10 min was homogenized in a food mixer. To monitor the efficacy of the stearate combination, their combined blend into the Tatrene HPF powder was added to the polypropylene Tatren TF 411 at a suitable ratio calculated on the final fiber. Therefore, the stearate mixture was fed into a secondary extruder with a screw diameter of 32 mm, where it was melted and then blended with a polypropylene melt of Tatren TE 451 in a base melt aggregate with a screw diameter of 90 mm.

245055

Conditions of melting and spinning of sticks: temperatures of the extruder

I. zone from 250 to 260 ^C C,

II. zone 255 to 260 G,

III. zone 255-260 ° C;

sub-extruder capacity 11.524 kg / h;

the heating temperature of the pipe sleeve between the secondary extruder and the base melting unit 260 ° C;

resistive heating temperatures of base melt aggregates 245 to 260 ^and C;

Temperature of vinyl vapors at basic melting aggregate:

Zone I 250 to 260 ° C,

BJECTIVE zone ^C1 250-260 C;

temperature of the vinyls in the distribution lines 250 ° C;

a spinning station temperature of 250 to 260 ° C;

melt pressure downstream of the melting portion of the basic melting aggregate of 6.9 MPa, downstream of the delivery pump of not more than 9 MPa, downstream of the secondary extruder of 5.9 MPa;

basic melting aggregate capacity 55.8 kg / h;

melt feed at a single spinning site of 310 g / min;

spinnerets with Y-holes;

retractor speed PD-1 450 m / min;

total titre of unreinforced fiber 7 040 to 7 780 dtex.

Comparative sample of granulated polypropylene TEREN TE 451 without addition of stearates was simultaneously dosed into the secondary extruder and the base.

The melt index test at 230 ° C in g / 10 min below the melt spinneret, melted and spun under the same conditions as in the above stearate test. Debting was carried out on KK-2 machine:

temperatures - galets upper 120 to 125 ° C and lower 104 ° C, irons 45 to 70 ° C;

speeds - dump 287 to 288 m / min, galets under iron 270 to 271 m / min, upper galets 338 to 340 m / min;

stresses - between 6th and 7th roller 200 to 210 cN, while winding 700 to 800 cN.

The twisting of the fiber on the "Verdol" machine was carried out under normal conditions. The efficacy of the combination of calcium stearates 0.2% by weight and zinc zinc 0.2% by weight was measured. j. without polypropylene cable fiber pigments (A). The obtained values were compared with the values of the cable fiber of granulated polypropylene Tatren TE 451 without addition of stearates (OJ. Physico-mechanical properties and other parameters of prepared fiber and twisted test A in a total titer of 2,724 dtex allowed its classification to the first quality.

It can be seen from Table 1 that the formed nonwoven fiber waste produced is much smaller when added to polypropylene by a combination of 0.2% by weight calcium zinc stearate and 0.2% by weight zinc zinc. This effect of the above stearate mixture is new and higher. In this small amount of stearate mixture, the flowability of the melt considerably increases, considering the increase in the melt index, which allows a reduction in energy costs.

Observations during the tests showed that for the fiber containing the calcium stearate combinations 0.2 wt. and zinc 0.2 wt. the spinning and digestion process is easier than the fiber from Tatrene TE 451 alone without the addition of stearates. However, in the case of the densified non-woven fiber with the added stearates in the above combination, the defect of "small strings (capillaries)" was not seen, unlike the fiber from Test O.

Scrapped nonwoven fiber waste (%)

13.89

6.68

1.9

15.7

Example 2

Prepared in a blender either 15% w / w. % zinc stearate mixture or 15 wt. calcium stearate into powdered polypropylene Tatren HPF was remelted in an extruder with a screw diameter of 28 mm, and the formed strings were cut into granules on a cutting apparatus. To monitor the efficacy of the stearate combination, the ingredients were dosed at the necessary ratio calculated on the final fiber.

Mechanical mixing of pigment concentrates with 15% w / w. % of a mixture of zinc stearate together with 15 wt. of the calcium stearate mixture was carried out in a food mixer for 10 min. The homogenized mixture of pigments and stearates was fed by means of a dispenser into a secondary extruder with a screw diameter of 45 mm, where it was melted and then blended with a melt of the polypropylene brand Mosten 56 532 in a basic melt aggregate with a screw diameter of 90 mm. The melting and spinning conditions were: temperature of the secondary extruder

Zone I 255 ° C,

II. zone 230 ° C,

III. zone 230 ° C;

the temperature of the tube between the secondary extruder and the base melt aggregate 230 ° C;

the temperature of the vinyls of the basic melt aggregate is 297 ° C; filter temperature 280 ° C;

temperature of the vinyls at distribution branches 285 ° C;

Table 2

Test Melting index at 230 ° C in g / 10 min under spinneret

A 13.8 .21.60

O 11.3 24.46

The values obtained were compared with the values of the polypropylene fiber which contained the above-mentioned pigments without the addition of stearates (O), i. j. it was a fiber made under the same conditions, equipment and average quantity.

The physico-mechanical properties of the prepared A and twisted fibers of Test A in a total titer of 4,071 dtex were:

tear strength of 1.69 to 1.72 cN / dtex; elongation at market 53.1 to 66.2%; softening 17.0 to 24.0%; shrinkage of 1.9 to 3.1%;

melt feed per spin site 300 g / min;

pulling speed of winding machine NSK-3 460 m / min;

a total titer of unreinforced fiber of 6,680 as well as 3,290 dtex;

the retention of the preparation on the undrawn fiber 13.39 percent.

The non-crosslinked fiber has been mined and shaped on a "Pneutex" aerating machine under the conditions of:

3, a relaxation ratio of 0.745, a speed of 1 300 m / min, a drawing temperature of 123-135 ° C.

The number of breaks was judged from the obtained number of irregular to its weight of vessels and was expressed per tonne of fiber produced consisting of regular and irregular vessels. The efficacy of the calcium stearate combination of 0.08 wt. % and zinc 0.13 wt. into a polypropylene fiber in the presence of pigments

Cromophtal gelb GR 0.0744 wt%, Cromophtal scharlach R 0.0156 wt%, Nylophil schwarz BLN 0.0186 wt% {AJ.

Essentially, the efficacy of the above stearate combination into one of the most difficult to process pale shades of polypropylene cable fiber was monitored.

Number of breaks per tonne of unreinforced, unreinforced fiber

Scraped non-woven fiber waste,%

42,5 6

110,90 10 number of broken capillaries per 50 m fibers 2,2;

number of twists 35 m ^-1 ;

titre deviation +1.78 ° / o.

The fiber was classified in the first quality. From Table 2 it can be seen that the number of breaks per tonne and hence the produced nonwoven fibrous waste produced is much less when adding to the polypropylene a combination of calcium stearates of 0.08% by weight. % and zinc 0.13 wt. In this small amount of stearate mixture, the flow rate of the melt increases by considering the increase in the melt index, which allows a reduction in energy costs.

The effect of stearates is also of practical importance for the desired improved properties of polymer systems with deteriorated prehistory, such as waste. The aforementioned invention is of application importance for reducing breakage and reducing the amount of waste in the dredging of polypropylene fibers prepared from conventional raw materials, various types and forms of wastes, as well as mixtures of wastes with conventional raw materials.

Other possibilities for use and advantages of the invention are:

- decreasing or increasing the orientation, degree of crystallinity and secondary crystallization of non-crosslinked fibers;

- a slight suppression of the increased crystallinity of the polypropylene due to the influence, certain content and types of pigments which make the polymer difficult to spin, the fiber being quite hard, inelastic and increasing the amount of waste;

- regulating the structure, elasticity, shrinkage and stiffness of the staple fibers, including those used for the hygienic plastic goat;

- increasing or decreasing the thermal stability or degradation of polypropylene, which may be of application in the preparation of both classical and coarse fibers;

- the possibility of improving physical and antistatic properties, reducing friction and stickiness to the warm metal surfaces of production machines and equipment, avoiding changes in fiber color;

- the possibility of reducing energy consumption, preparation, stabilization and dispersion systems;

- the possibility of carrying out the digestion process under more severe conditions;

- reducing defects and color streaks of the fibers.

Claims (1)

SUBJECT Use of a mixture of zinc and calcium stearates as an additive to polypropylene to reduce breakage and reduce the amount of waste when splitting polypropylene fibers.