JP2001192511A - Processability improver and polyolefin composition using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processibility-improving agent capable of enhancing processibility of a polyolefin such as a linear, low-density polyethylene and the like without detriment to excellent characteristics the polyolefin originally possesses and to provide a polyolefin composition using the processibility- improving agent. SOLUTION: The processibility-improving agent comprises a polyethylene having a number-average mol.wt. (Mn) of 1,000-10,000 and a weight-average mol.wt. (Mw) to number-average mol.wt. (Mn) ratio (Mw/Mn) of 4.0-7.0. The polyolefin composition comprises 5-40 wt.%, based on the polyolefin, of the processibility-improving agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a processability improver and a polyolefin composition using the same.

[0002]

2. Description of the Related Art Various types of polyethylene are known, including low-density polyethylene and high-density polyethylene, ultra-low-density polyethylene, and linear low-density polyethylene.
Utilizing their respective features, they are widely used in various applications from household goods to industrial products. Of these, linear low-density polyethylene (density of 0.94 or less) produced using a Ziegler-based catalyst by the medium-to-low pressure method requires less energy consumption for production and has properties not available in low-density polyethylene by the high-pressure method. , The demand tends to increase more and more. A metallocene-catalyzed linear low-density polyethylene (a copolymer of ethylene with an α-olefin such as butene, propylene, hexene, octene, etc. using a metallocene catalyst) has also been developed for strength and transparency. , Because of its excellent heat-sealing properties, as an alternative to conventional low-density linear polyethylene with Ziegler catalyst
Demand is expected to increase as the use of polyethylene is further expanded.

[0003] However, these linear low-density polyethylenes have the above-mentioned excellent characteristics, but have a problem that they are poor in workability in molecular structure.

Therefore, in order to improve the processability of these polyethylenes, it is common practice to add low molecular weight polyethylene having a molecular weight of about 2000, ie, polyethylene wax.

[0005] However, in order to obtain a sufficient effect of improving processability, a large amount of polyethylene wax must be added, and the excellent properties inherent to the linear low-density polyethylene may be impaired.

[0006]

As described above, in conventional linear low-density polyethylene, polyethylene wax is generally added because of poor processability. In order to obtain the effect, a large amount of polyethylene wax must be added, and there has been a problem that the excellent characteristics inherent in the linear low-density polyethylene are impaired.

The present invention has been made in order to solve such problems, and a processability improving agent capable of improving processability of linear low-density polyethylene and the like without impairing the excellent properties inherent in them. And a polyolefin composition using such a processability improver.

[0008]

The processability improver of the present invention has a number average molecular weight (Mn) as described in claim 1.
Is 1000 to 10,000 and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 4.0 to 7.0.

In the above processability improver, the processability of polyolefin having poor processability such as linear low density polyethylene can be enhanced with a small amount of addition. Therefore, the processability can be improved without impairing the excellent properties inherent in such a polyolefin.

[0010] In the processability improver of the present invention,
As described in claim 2, the polyethylene is preferably obtained by hydrolyzing and / or thermally decomposing the crosslinked polyethylene using supercritical water or subcritical water as a reaction solvent. It can be used.

Further, the polyolefin composition of the present invention comprises:
As described in claim 4, a composition comprising a polyolefin as a base polymer, wherein the processability improver of the present invention is used as a processability improver in an amount of 5 to 5% of the polyolefin.
It is characterized by containing up to 40% by weight.

In such a polyolefin composition, a number average molecular weight (Mn) of 1000 is used as a processability improver.
Excellent characteristics inherent to polyolefins by containing a predetermined amount of polyethylene having a weight-average molecular weight (Mw) and a number-average molecular weight (Mn) of 4.0 to 7.0 (Mw / Mn) of up to 10,000. And excellent workability.

The polyolefin composition of the present invention is particularly useful when the polyolefin contains a linear low-density polyethylene, as described in claim 5.

[0014]

Embodiments of the present invention will be described below.

The processability improver of the present invention has a number average molecular weight (Mn) of 1,000 to 10,000 and a weight average molecular weight (M
w) and the ratio (Mw / Mn) of the number average molecular weight (Mn) is 4.
It consists of polyethylene of 0 to 7.0.

The number average molecular weight (Mn) and the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw / M
If any of n) is outside the above range, the effect of improving the processability of the polyolefin may be insufficient, or the physical properties of the polyolefin, such as electrical properties, may be reduced. In the present invention, the number average molecular weight (Mn)
Is more preferably 3000 to 10,000 and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 5.0 to 7.0.

The above-mentioned polyethylene can be produced by decomposing cross-linked polyethylene using supercritical water or subcritical water as a reaction solvent. That is, for example, by contacting the pellet-shaped or chip-shaped crosslinked polyethylene with supercritical water or subcritical water at a temperature of 200 ° C. to 1000 ° C. and a pressure of 2 MPa to 100 MPa for about 1 minute to 60 minutes, the number average molecular weight (Mn) ) Of 1,000 to 10,000 and a ratio (Mw / Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) of 4.0 to 7.0 can be obtained.

Here, as the crosslinked polyethylene,
Use of the waste of the crosslinked polyethylene product is advantageous in that the waste can be effectively used.

The processability improver of the present invention can improve the processability of a polyolefin such as a linear low-density polyethylene with a small amount of use, and therefore has excellent characteristics inherent in such a polyolefin. Workability can be improved without loss.

Next, the polyolefin composition of the present invention will be described.

The polyolefin composition of the present invention contains a polyolefin and the above-mentioned processability improver of the present invention.

Polyolefins include low density polyethylene (LDPE), medium density polyethylene polyethylene (MDPE), high density polyethylene (HDPE), very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), polypropylene, ethylene -Propylene copolymer (EP), ethylene-propylene-diene terpolymer (EPDM), polyisobutylene, ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), ethylene·
Examples include an ethyl methacrylate copolymer, an ethylene / vinyl acetate copolymer (EVA), and a mixture thereof. In the present invention, a large effect can be obtained particularly when a linear low-density polyethylene having poor processability is contained.

The processability improver of the present invention is blended with such polyolefin in the range of 5 to 40% by weight.
If the compounding amount is less than 5% by weight, the processability becomes insufficient, and if the compounding amount exceeds 40% by weight, properties such as electrical properties of the polyolefin may be deteriorated. More preferred amount is 5% by weight to 35% by weight based on polyolefin.
And more preferably in the range of 5% by weight to 30% by weight.

The polyolefin composition of the present invention contains, in addition to the above components, an antioxidant, a crosslinking agent, a crosslinking accelerator, a filler, a conductive agent, which are usually blended with the polyolefin as long as the effects of the present invention are not impaired. Granting agents, plasticizers, softeners, coloring agents, lubricants, stabilizers, and other additives can be added as necessary.

The composition of the present invention has a number average molecular weight (Mn) of 1,000 to 10,000 and a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), incorporated as a processability improver. Mw / Mn) is from 4.0 to 7.0 polyethylene,
The processability is improved, and the polyolefin has excellent characteristics inherently possessed.

[0026]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 A sample of 1 cm × 1 cm × 1 mm was cut out from a sheet made of cross-linked polyethylene for electric wires and cables (gel fraction: 80 %, chemically cross-linked), and this sample was pressure-resistant to a reaction vessel (capacity: 50 cc) together with 20 cc of pure water. I put it in. Next, the reaction vessel is sealed and heated to reduce the temperature and the internal pressure of the reaction vessel to 40, respectively.
Raise the temperature and pressure to 0 ° C and 40 MPa for 30 minutes,
(Reaction time: 1 minute). Thereafter, the mixture was cooled over 2 hours to return to normal temperature and normal pressure, and solids were separated and recovered from the reaction solution (yield: about 100%).

The obtained solid content was 0.4% in gel fraction and 1 in melting point.
10 ° C. Gel permeation chromatography (G
PC), the number average molecular weight (Mn) of 5000,
Number average molecular weight (Mw) 30,000, their ratio (Mw / M
n) was found to be 6.0 polyethylene.

Next, 10% by weight of the above polyethylene was added to a linear low-density polyethylene (trade name: Evolu, manufactured by Mitsui Petrochemical Industry Co., Ltd.) using a metallocene catalyst, and kneaded at 170 ° C. for 10 minutes with a kneader to form a sheet. Extruded into
The workability and insulation properties were evaluated by the appearance of the sheet and the AC breakdown voltage, respectively. Table 1 shows the results.

Examples 2 and 3 Sheets were prepared in the same manner as in Example 1 except that the amount of polyethylene obtained by decomposing crosslinked polyethylene for electric wires and cables was changed to 20% by weight and 30% by weight. Then, its workability and insulation properties were evaluated by the appearance of the sheet and the AC breakdown voltage, respectively. Table 1 shows the results.

Example 4 A sheet made of the same crosslinked polyethylene for electric wires and cables as in Example 1 (gel fraction: 80 %, chemically crosslinked) was 1 cm ×
A sample of 1 cm × 1 mm was cut out, and this sample was put into a pressure-resistant reactor (capacity: 50 cc) together with 6 cc of pure water. Then
The reaction vessel was sealed and heated to raise the temperature and internal pressure in the reaction vessel to 400 ° C. and 25 MPa, respectively, over a period of 30 minutes and held for 1 minute (reaction time: 1 minute). Thereafter, the mixture was cooled over 2 hours to return to normal temperature and normal pressure, and solids were separated and recovered from the reaction solution (yield: about 100%).

The obtained solid content was 0.6% in gel fraction and 1 in melting point.
10 ° C. As a result of analysis by GPC, it was found that the polyethylene was a polyethylene having a number average molecular weight (Mn) of 7000, a number average molecular weight (Mw) of 43000, and a ratio (Mw / Mn) of 6.1.

Next, 20% by weight of the above polyethylene was added to the same metallocene-catalyzed polyethylene as in Example 1, kneaded with a kneader at 170 ° C. for 10 minutes, and extruded into a sheet. Each was evaluated by the appearance of the sheet and the AC breakdown voltage. Table of results
Shown in 1.

Example 5 A 1 cm × 1 cm sheet made of the same crosslinked polyethylene for electric wires and cables (gel fraction 80 %, chemically crosslinked) as in Example 1
A sample of 1 cm × 1 mm was cut out and placed in a pressure-resistant reaction vessel (50 cc capacity) together with 4 cc of pure water. Then
The reaction vessel was sealed and heated to raise the temperature and internal pressure in the reaction vessel to 400 ° C. and 20 MPa, respectively, over a period of 30 minutes, and then held for 1 minute (reaction time: 1 minute). Thereafter, the mixture was cooled over 2 hours to return to normal temperature and normal pressure, and solids were separated and recovered from the reaction solution (yield: about 100%).

The obtained solid content was 0.5% in gel fraction and 1 in melting point.
10 ° C. As a result of analysis by GPC, it was found that the polyethylene had a number average molecular weight (Mn) of 7000, a number average molecular weight (Mw) of 48000, and a ratio (Mw / Mn) of 6.9.

Next, the above polyethylene was added to polyethylene with the same metallocene catalyst as in Example 1 in an amount of 20% by weight, kneaded with a kneader at 170 ° C. for 10 minutes, and extruded into a sheet. Each was evaluated by the appearance of the sheet and the AC breakdown voltage. Table of results
Shown in 1.

In Table 1, comparative examples are shown as follows:
Comparative Example 1 was an example in which the decomposition product of crosslinked polyethylene was not blended, and Comparative Examples 2 to 4 were polyethylene wax (Mn = 1500, Mw =
5000, Mw / Mn = 3.3) were added at 10% by weight, 20% by weight, and 30% by weight, all of which are shown for comparison with the present invention.

[0038]

[Table 1] As is clear from Table 1, in Examples according to the present invention,
Workability can be improved without impairing the insulating properties.

[0039]

As described above, according to the processability improver of the present invention, the processability of polyolefins such as linear low-density polyethylene can be improved with a small amount of use. Workability can be improved without impairing excellent characteristics. Also,
Since the polyolefin composition of the present invention contains such a processability improver in a predetermined amount, it has excellent properties inherent to polyolefin and excellent processability.

Continuation of the front page (72) Inventor Fumio Aida 2-1-1, Oda-Ei, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside Showa Electric Wire & Cable Co., Ltd. (72) Susumu Hirai 2-1-1, Oda-Ei, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture No. 1 Inside Showa Electric Wire & Cable Co., Ltd. (72) Inventor Hiroaki Morita 2-1-1 Oda Sakae, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture F-term inside In Showa Electric Wire & Cable Co., Ltd. 4J100 AA02P CA01 CA31 DA01 DA04 HA51 HA53 HE12 JA00

Claims (5)

[Claims] Claims: 1. A number average molecular weight (Mn) of 1,000 to 10,000
And the weight average molecular weight (Mw) and the number average molecular weight (M
A processability improver comprising a polyethylene having a ratio (Mw / Mn) of 4.0 to 7.0 with respect to n). 2. The processability improver according to claim 1, wherein the polyethylene is obtained by thermally decomposing the crosslinked polyethylene using supercritical water or subcritical water as a reaction solvent. 3. A reaction temperature of 200 ° C. to 1000 ° C., and
3. The processability improver according to claim 2, wherein the reaction pressure is 2 Mpa to 100 Mpa. 4. A composition comprising a polyolefin as a base polymer, having a number average molecular weight (Mn) of 1000 to 10 as a processability improver.
000 and a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw / Mn) of 4.0 to 7.0, wherein the polyethylene is 5 to 40% by weight based on the polyolefin. Polyolefin composition. 5. The polyolefin composition according to claim 4, wherein the polyolefin comprises a linear low-density polyethylene.