Polyolefin composition

 

(57) Abstract:

Polyolefin composition is intended for application in the automotive industry, the engineering and construction industry. The composition contains as crystalline (co)polymer 1-olefin (co)polymer with a melt index of 25 g/10 min or higher, and dispersed (co)polymer cellulose material in the form of particles or fibers. The combination of components in a certain ratio and, under certain conditions, enables the manufacture of complex-shaped products injection molding at 200oC and below. 7 C.p. f-crystals, 1 table.

The invention relates to compositions that include crystalline polymers and copolymers of 1-olefins, in particular propylene, and cellulose materials, in particular wood flour and fibers dispersed in the above-mentioned polymers.

The above composition is obtained by preparing compositions in pellet form, which are products.

Composition based on olefin polymers, in particular of crystalline polypropylene, filled with wood flour, are already known. Thanks to the low cost and the small proportion (approximately tow, widely used in automobile industry, engineering and construction industry. However, some of the physico-mechanical properties of these materials are low or only satisfactory, in particular the dimensional stability at temperatures higher than room temperature, for example at 40 - 70oC, which is a mandatory requirement in most cases in the above mentioned fields of application, for even extended periods of time. In addition, the products of these compositions can only be made by molding a sheet of thermoplastic (before they were made using the extruder with a slit extrusion head) in very moderate conditions of production (in particular at temperatures below 200oC). However, this technique does not allow to produce products of complex shape without waste (off-cuts) during fast molding cycle. To address this problem, you should resort to the technique of injection molding with the use of appropriate forms, as described in SU auth. St. 1100288 class. C 08 L 23/12, 1984, which is the prototype, however, the implementation of this technology requires much more stringent conditions overtime 220 - 230oC, that is, conditions in which the pulp phase could result in considerable destruction, because of what the finished product might acquire an unpleasant smell, poor appearance and poor mechanical properties. In addition, while forming equipment, and the forms could be exposed to destructive corrosion.

The author found that the above drawbacks can be eliminated, it is possible to apply the technique of injection molding, but to carry out the process at temperatures that do not exceed 200oC, which enables to produce during rapid cycles of molding articles of complex shape, if the composition, and which comprises cellulosic material, prepared with the use of polyolefins with low values of molecular weight, corresponding to the values of melt index (IR at a temperature of 230oC, 2,16 kg in accordance with the standards ASTM-D 1238, condition L) greater than 25, preferably in the range at 25 1000 g/10 min, more preferably in the range of 30-400 g/10 min.

The technical problem of the present invention is solved by using the polyolefin composition comprising one or more crystalline polymers or copolym the but - from 30 to 400 g/10 min, and dispersed in the above polymers or copolymers of cellulose material in the form of particles or fibers.

The polymers are introduced into the compositions of the invention, it is preferable to choose from crystalline polymers and copolymers of linear or branched 1-olefins whose molecules f 2 to 10 carbon atoms. Particularly preferred is polypropylene, and more specifically on the merits of stereoregular polypropylene, index stereoregularity which is not less than 90% (the content of the fraction not soluble in boiling n-heptane, in percent.

The above polyolefins prepared in accordance with well known technology of polymerization using coordination catalysts, in particular catalysts of the Ziegler-Natta.

Olefinic polymers with large quantities of melt index, in particular those which are required in accordance with the invention, can be obtained, as is well known, an adequate reduction of the molecular weight of polyolefins by regulated processes of thermal decomposition, for example, by thermo-mechanical processing, possibly in the presence of initiators radial polymerization, cahnce destructively, by an adequate increase of the content of the molecular weight regulator, commonly used during the process with a catalyst of Ziegler-Natta (in particular hydrogen).

The preferred cellulosic material shall be constructed of wood flour or fiber with an average size (diameter or length) in a wide range, but is usually from 0.01 to 5 m, and a bulk density of 0.05 - 0.3 g/cm3.

The amount of cellulosic material, which enter in the composition of the present invention can be varied within a wide range depending on the desired physical and mechanical properties of the finished product. For the above purposes, however, the preferred content is from 10 to 70 wt.% in terms of the total weight of the composite material.

In accordance with the present invention the extrusion of blends of cellulosic material with a polyolefin, in particular propylene, possessing the above characteristics, allows to obtain granules with the use of well-known technology injection moulding and equipment for its implementation can be subjected to conversion into products very complex shape, material which by its physical-mechanical charakteristiken molding a sheet of thermoplastic, as outlined above. Thus, in particular, products of the present invention have improved rigidity and dimensional stability at room and higher temperatures (not below the 100oC), which is clearly confirmed by the higher values of modulus of bending and TTD (heat distortion temperature).

Moreover, during the process of molding articles of the present invention the phenomenon of degradation of the cellulose component is negligibly weak or extremely cautious even in those cases, when the contents of the specified component is very high (40 - 70 wt.%). Thus, manufactured this product have greatly improved organoleptic properties (odor and color).

Finally, in comparison with the compositions of polypropylene and wood flour, which is currently supplied to the market, the materials of the present invention is less sensitive to water absorption or moisture, which leads, therefore, to such advantages as storage stability and improved appearance of the finished products.

In General, good organoleptic, physical and mechanical properties and low cost products that make up the object n industry, the engineering and construction industry, where they can displace not only produced up to the present time of the composition of polypropylene and wood flour, but also other materials, such as resin plant polymers (ABC) and polypropylene, reinforced with glass fibre and polypropylene filled with talc. Moreover, as has been established, which is another object of the present invention, further improvement of physico-mechanical and organoleptic characteristics can be achieved in the case where the composition includes substances which act as agents, indicating the compatibility of the two phases, i.e. polyolefin and cellulose material. These substances can be selected from the already known and produced agents, indicating the compatibility of that use for composites of polyolefins with organic or mineral fillers, such as titanium alcoholate, esters of phosphoric, phosphorous, phosphonic and silicic acids, metal salts and esters of aliphatic, aromatic, cycloaliphatic acids, copolymers of (ethylene) acrylic and methacrylic acids, ethylene (acrylic esters) and metacello is (MBS), styrene-Acrylonitrile (SAN), styrene-Acrylonitrile copolymers, polyolefins, in particular polyethylene and polypropylene modified by grafting of polar monomers, in particular maleic anhydride and its esters, acrylic and methacrylic acids and esters, vinyl acetate and styrene. The above agents compatibility can be added in amounts in the range of 0.1 - 10 wt.%, preferably from 0.5 wt.%, in terms of the total weight of the composition.

As indicated above, the compositions of the present invention can easily be prepared in granular form by extrusion with conducting the process at a temperature not exceeding 200oC, preferably 170 to 200oC.

With this purpose it is possible to use any known equipment and technology. Especially preferred are twin screw extruder with screws rotating in the same direction with high homogenization capacity, equipped with mnogofigurnoe head and cold cutting device, which cuts the beam extrudable rods into pieces-granules.

The use of known equipment for injection formation and technology in combination with process while vysheukazannye of the process of preparing granules in addition to the two main components (polyolefin and cellulose material) and, perhaps a certain amount of agents compatibility in the extruder, you can enter other additives, in particular stabilizers against heat, light, UV radiation), plasticizers, pigments or dyes, antistatic agents and waterproofing agents.

Example 1. During the experiment, as the equipment used extruder mixer MARIS (Turin) TM 85, equipped with rotating in the same direction screws whose length is 36 times the screw diameter.

Example 2. Repeat the experiment of example 1, but in this case, use polypropylene in the form of spherical particles with IL (L90 g) for 10 min and the rate of stereoregularity 93%.

Characteristics of the prepared compositions are summarized in table.

Example 3. Repeat the experiment of example 1, but in this case, use polypropylene in the form of spherical particles with IL (L 150 g) for 10 min and the rate of stereoregularity 96%.

Characteristics of the prepared compositions are presented in the table.

Example 4. In the experiment, use the equipment and procedures of example 1, but in this case, nutritious hole of the extruder enter to 45.5 wt.h. polypropylene in granular form with IL (L 35 g) 10 min philena, modified grafted copolymerization containing approximately 5 wt.% maleic anhydride as agent compatibility.

1/3 the length of the extruder after a filling holes in the extruder serves 50 wt.h. wood flour type "50".

Characteristics of the prepared compositions are presented in the table. From their comparison with characteristics for example 1 is obviously a significant improvement in the heat distortion temperature (TTD) thanks to the use of agent compatibility.

Example 5. Repeat the experiment of example 4, but in this case, the use of polypropylene in the form of spherical particles with IL (L 400 g) for 10 min and the rate of stereoregularity 97%.

To the feed opening of the extruder enter a 46.5 wt.h. polypropylene in granular form with IL (L 35 g) for 10 min and the rate of stereoregularity (the content of a fraction soluble in boiling n-heptane, in percent) 97%, and 0.3 wt.h. antioxidant additives IRGANOX 225 [mixture mass ratio of 1:1 Tris/2,4-di-tert.-butylphenyl/-phosphite with pentaerythrityl-tetrakis-[3-/3,5-di-tert. -butyl-4 oksifenil-propinate] mixed with 3.2 wt.h. propylene and at a point located at 1/3 of the length of the extruder from the filling hole in rasplavu use of wood flour with the following characteristics: bulk density: approximately 0.15 g/cm3.

The distribution of particle sizes:

Diameter in mm - Mass fraction,%

More 0,500 - 3

0,500 - 0,355 - 2

0,355 - 0,250 - 30

0,250 - 0,180 - 23

0,180 - 0,090 - 17

Less 0,090 - 7

The temperature within the extruder is maintained at 180 - 190oC. output material granularit using cold cutting beam extrudable bars.

Then, these pellets are used to make the samples by injection formation at 170oC for these samples to determine the following parameters: specific gravity (g/cm3ASTM d-1505), bending modulus MEF (MPa 23oC, ASTM d-790 and the heat distortion temperature TTDoC, 1,82 H/mm2, ASTM d-648).

Thus obtained results are summarized in table.

The characteristics presented in the table, you can see the improvement value TTD due to the introduction into the composition of the agent compatibility.

Example 6 (comparative). Repeat the experiment of example 4, but in this case, use granulated polypropylene IL (L 1.8 g) 10 minutes

From the table it is obvious that the prepared composition has values of modulus of bending and TTD, which are significantly worse than these same characteristics, dostie agent compatibility. While the organoleptic properties of the pellets and molded samples also much worse.

Example 7. The polypropylene used in the experiment of example 1 (IL/L = 35 g/10 min), and subjected to thermo-mechanical degradation at 200oC in the extruder MARIS TM 35 in the presence of 0.4 wt.% product TRIGONOX 101 [bis-/tert. butylperoxyisopropyl/-benzene].

The thus treated polypropylene, IL (L which is 400 g/10 min), then used in the preparation of compositions with the use of wood flour in the experiment described in example 1.

Characteristics of the specified composition is presented in table.

1. Polyolefin composition comprising crystalline (co)polymer of 1-olefins and dispersed (co)polymer cellulose material in the form of particles or fibers, characterized in that the crystalline (co)polymer of 1-olefins, it includes a (co)polymer with a melt index, as measured by S 1238, condition L at 230oC and a load of 2.16 kg, of from 25 g/10 min and above in the following ratio, wt.%:

Cellulosic material - 10 - 70

Crystalline (co)polymer of 1-olefins - Rest

2. The composition according to p. 1, characterized in that nayasa fact, it includes cellulosic material with an average particle size of from 0.01 to 5 mm

4. The composition according to p. 1, characterized in that it includes as a (co)polymer of 1-olefins, crystalline polymers and copolymers of linear or branched C2- C10-1-olefins.

5. The composition according to p. 4, characterized in that the (co)polymer of 1-olefins it includes polypropylene.

6. The composition according to p. 1, characterized in that it further includes 0.1 to 10 wt.h. agent compatibility on 100 wt.h. song.

7. The composition according to p. 6, characterized in that the agent compatibility it includes polypropylene grafted maleic anhydride.

8. The composition according to p. 1, characterized in that it has the form of extruded pellets.

 

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FIELD: polymer materials.

SUBSTANCE: invention relates to stabilizer mixture used for stabilizing polyolefin against destruction initiated by visible light, heat, or oxidation and to thus stabilized polyolefin. Stabilizer mixture comprises spatially hindered amine compound and polymer containing polar residues, weight ratio of the two compounds being between 20:1 and 1:20, respectively, provided that (i) polymer cannot be the same compound as hindered amine compound and does not contain groups of formula (1) or (II): . Where G represents hydrogen atom or methyl and G1 and G2, independently of each other, each represents hydrogen atom or methyl or they together form =O; and (ii) polymer cannot contain acidic hydrogen atom.

EFFECT: considerable increased efficiency of stabilizer composition.

22 cl, 4 tbl, 4 ex

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