JP2814337B2 - Polypropylene having high melt tension, method for producing the same and molded article - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to polypropylene having a high melt tension. More specifically, a polypropylene having a high melt tension and a high crystallization temperature, having excellent rigidity and moldability, and having a high melt tension capable of being used again as a molded article, then being re-melted and recycled. And molded articles.

[0002]

2. Description of the Related Art Crystalline polypropylene has mechanical properties,
It is widely used in various molding fields because it has excellent chemical resistance and is very useful in balance with economic efficiency. However, since the melt tension is low and the crystallization temperature is low, the moldability such as hollow molding, foam molding, and extrusion molding is poor.

As a method for increasing the melt tension and crystallization temperature of crystalline polypropylene, a method of reacting an organic peroxide and a crosslinking assistant with crystalline polypropylene in a molten state (JP-A-59-93711, JP-A-61-
No. 152754), however, there is a problem that the modified polypropylene obtained by using the crosslinking aid has an odor remaining. In addition, the melt tension is not sufficiently improved, and if the amount of the organic peroxide and the crosslinking aid is increased to increase the melt tension, a gel will be generated. It was impossible to do that.

On the other hand, Japanese Patent Application Laid-Open No. 2-298536 discloses that a polypropylene having a free-end long-chain branch and containing no gel is prepared by reacting a semi-crystalline polypropylene with a peroxide having a low decomposition temperature in the absence of oxygen. Although a method for obtaining the polypropylene has been disclosed, improvement in the melt tension of the obtained polypropylene has been insufficient.

[0005]

As described above, the polypropylene obtained by the method of the prior application has insufficient melting tension and crystallization temperature, has an odor, and contains a gel. After using it as a molded product,
There was a problem that it was impossible to re-melt and use it for recycling.

[0006] The present inventors have solved the problems of the above-mentioned known inventions and have intensively studied a polypropylene suitable for hollow molding, foam molding, extrusion molding and the like, and a method for producing the same. As a result, a specific organic peroxide is reacted with a polypropylene having a wide molecular weight distribution under specific conditions, and further melt-kneaded to obtain a polypropylene having a specific structure and properties.If the polypropylene is used as a molded article, The inventors have found that the problems of the known invention can be solved, and have reached the present invention.

As is apparent from the above description, it is an object of the present invention to provide a material having extremely high melt tension and crystallization temperature, excellent rigidity and moldability, and after being used as a molded article, remelted and recycled. Another object of the present invention is to provide a polypropylene which can be used, a method for producing the same, and a molded article using the polypropylene.

[0008]

The present invention has the following constitutions (1) to (10). (1) Linear crystalline polypropylene having a branching index of substantially 1 and (A) a melt tension (MS) at 230 ° C. and an intrinsic viscosity [η] measured at 135 ° C. in tetralin. And log (MS)> 4.24 × log [η] −0.685, and (B) a differential scanning calorimeter (DS)
Crystallization temperature (Tc) and melting point (Tm) measured by C)
Satisfies the relationship of (Tc)> 0.784 × (Tm) −4.00, (C) the boiling xylene extraction residual ratio is 1% by weight or less, and (D) the weight average molecular weight (Mw) /
A polypropylene having a number average molecular weight (Mn) value (Q) of 7 to 30.

(2) The polypropylene according to the above (1), wherein the crystalline polypropylene is a propylene homopolymer.

(3) The polypropylene according to the above (1), wherein the crystalline polypropylene is a propylene-olefin random copolymer containing 10% by weight or less of olefin polymerized units other than propylene.

(4) The value of weight average molecular weight (Mw) / number average molecular weight (Mn) (Q) in an inert gas atmosphere
Is 6 to 30, linear crystalline polypropylene 10
0-10 g of di-2-ethylhexyl peroxydicarbonate was added and mixed per 0 g, and the mixture was mixed at 70-150 ° C.
(A) a linear crystalline polypropylene having a branching index of substantially 1 after reacting for 10 minutes to 3 hours under the temperature conditions of
Melt tension (MS) at 230 ° C and 1 in tetralin
The intrinsic viscosity [η] measured at 35 ° C. is expressed by the following relationship: log (MS)> 4.24 × log [η] −0.685, and (B) a differential scanning calorimeter (DS)
Crystallization temperature (Tc) and melting point (Tm) measured by C)
Satisfies the relationship of (Tc)> 0.784 × (Tm) −4.00, (C) the boiling xylene extraction residual ratio is 1% by weight or less, and (D) the weight average molecular weight (Mw) /
A method for producing a polypropylene having a number average molecular weight (Mn) value (Q) of 7 to 30.

(5) The method according to the above (4), wherein the crystalline polypropylene is a propylene homopolymer.

(6) The method according to (4), wherein the crystalline polypropylene is a propylene-olefin random copolymer containing not more than 10% by weight of olefin polymerized units other than propylene.

(7) After the reaction between the crystalline polypropylene and di-2-ethylhexyl peroxydicarbonate, the reaction is continued at 100 to 150 ° C. in an inert gas atmosphere.
The method according to the above (4), which comprises performing a post-heating treatment for 10 minutes to 3 hours.

(8) A linear crystalline polypropylene having a branching index of substantially 1, and (A) 230
Melt tension (MS) at 135 ° C and 135 ° C in tetralin
And (B) a differential scanning calorimeter (DS) with the intrinsic viscosity [η] measured by the following equation: log (MS)> 4.24 × log [η] −0.685.
Crystallization temperature (Tc) and melting point (Tm) measured by C)
Satisfies the relationship of (Tc)> 0.784 × (Tm) −4.00, (C) the boiling xylene extraction residual ratio is 1% by weight or less, and (D) the weight average molecular weight (Mw) /
A molded article using polypropylene having a number average molecular weight (Mn) value (Q) of 7 to 30.

(9) The molded article according to the above (8), wherein the crystalline polypropylene is a propylene homopolymer.

(10) The molded article according to (8), wherein the crystalline polypropylene is a propylene-olefin random copolymer containing 10% by weight or less of olefin polymerized units other than propylene.

The configuration of the present invention will be described in detail below. The polypropylene of the present invention contains not only propylene homopolymer but also 10 units of olefin polymer units other than propylene.
It also includes a propylene-olefin random copolymer containing less than about 10% by weight, and the description of polypropylene is used in this sense hereinafter.

The polypropylene of the present invention is a linear crystalline polypropylene having a branching index of substantially 1, and the branching index indicates the degree of long-chain branching. Defined. Branching degree index (g) = [η] Br / [η] Lin Here, [η] Br is the intrinsic viscosity of the branched polypropylene, and in this specification, is the measured value [η] Obs of the polypropylene of the present invention. Also, [η] Lin in the present specification,
In the method for producing the polypropylene of the present invention described below, the above [η] obtained by the same method as the linear crystalline polypropylene obtained by a known method used as a raw material
This is the intrinsic viscosity of a linear crystalline polypropylene having the same weight average molecular weight as the Obs sample. The above ratio of the intrinsic viscosity indicates the degree of branching of the non-linear polymer, and is less than 1 when a long-chain branch is present.

The intrinsic viscosity was measured at 135 ° C. on a sample dissolved in tetralin. Also,
Weight average molecular weight (Mw) and number average molecular weight (Mn)
By American Laboratory, Ma by MLMcConnell
y, 63-75 (1978), ie, low angle laser light scattering photometry.

The polypropylene of the present invention has a branching index according to the above definition and measuring method of substantially 1, and does not have a long-chain branched structure. In addition, being substantially 1 means that even if there is a long-chain branch, it is below the detection limit by the above method, and the range of statistical error when the same sample is repeatedly measured by the above method. It includes the meaning of 1 including. Therefore, a practical value is 0.
It shows a value of about 95 to 1.05. Since the degree of branching index is substantially 1, except for the characteristic properties of the polypropylene of the present invention described below, it has the same properties as the conventionally known linear polypropylene, so that the conventionally known linear It has a feature that the molding method and apparatus used for polypropylene can be used as they are.

Further, the polypropylene of the present invention has the following four essential requirements. That is, (A) a relationship expressed by log (MS)> 4.24 log [η] −0.685 between the melt tension (MS) at 230 ° C. and the intrinsic viscosity [η] measured in tetralin at 135 ° C. And (B) Differential scanning calorimeter (DS
Crystallization temperature (Tc) and melting point (Tm) measured by C)
Satisfies the relationship of (Tc)> 0.784 × (Tm) −4.00, (C) the boiling xylene extraction residual ratio is 1% by weight or less, and (D) the weight average molecular weight (Mw) /
It is characterized in that the value (Q) of the number average molecular weight (Mn) satisfies 7 to 30.

As described above, the melt tension of polypropylene required to achieve the object of the present invention is, as described above, the melt tension (MS) at 230 ° C. and the intrinsic viscosity [η] measured at 135 ° C. in tetralin. log (MS)> 4.24
log [η] −0.685, more preferably log (MS)> 4.24 log [η] −0.47
It is necessary that the relationship shown by 0 be satisfied.

Here, the melt tension at 230 ° C. (M
S) uses a melt tension tester type 2 manufactured by Toyo Seiki Seisaku-Sho, Ltd. to convert polypropylene into 230
℃, melted polypropylene 2.095mm in diameter
From the nozzle at a speed of 20 mm / min into the air at 23 ° C. to form a strand.
The tension of the filamentous polypropylene at the time of drawing at a rate of / minute was measured and defined as a melt tension (MS).

The crystallization temperature of polypropylene required to achieve the object of the present invention is, as described above, a crystallization temperature (Tc) and a melting point (Tm) measured by a differential scanning calorimeter (DSC). Is (Tc)> 0.784 ×
The relationship represented by (Tm) −4.00, more preferably the relationship represented by (Tc)> 0.784 × (Tm) −3.00, must be satisfied. If this relationship is not satisfied, the good moldability characteristics of the polypropylene of the present invention are lost due to slow crystallization.

The crystallization temperature (Tc) and the melting point (Tm) of the polypropylene were raised from room temperature to 230 ° C. under a heating condition of 30 ° C./min using a DSC7 differential scanning calorimeter manufactured by Perkin-Elmer. After holding at the same temperature for 10 minutes,
The temperature was lowered to -20 ° C at -20 ° C / min, and
After holding for 20 minutes, the temperature showing the maximum peak at the time of melting under a heating condition of 20 ° C./min was defined as a melting point (Tm). Further, after the melting point peak appeared, the temperature was continuously raised to 230 ° C. under the same conditions, and the temperature was maintained at the same temperature for 10 minutes.
The temperature was lowered to 50 ° C., and from 150 ° C., the temperature at which the maximum peak was reached during crystallization while the temperature was lowered at −5 ° C./min was defined as the crystallization temperature (Tc).

As described above, the polypropylene of the present invention must have a boiling xylene extraction residual ratio of 1% by weight or less, more preferably 0.6% by weight or less. If the extraction residual ratio is large, the moldability deteriorates, and it becomes extremely difficult to re-melt and recycle after use as a molded article.

The boiling xylene extraction residual ratio was determined by placing 1 g of polypropylene in a 200-mesh wire net using a Soxhlet extractor, extracting with 200 ml of p-xylene with boiling xylene for 6 hours, and drying and weighing the extracted residue. It was calculated as (weight of extraction residue / weight before extraction) × 100%.

The polypropylene of the present invention must have a weight average molecular weight (Mw) / number average molecular weight (Mn) value (Q) of 7 to 30, which is a measure of molecular weight distribution. If the molecular weight distribution (Q) is less than 7, the improvement of the melt tension is insufficient, and if it exceeds 30, the moldability is rather deteriorated and a gel is easily generated. Weight average molecular weight (M
w) and the number average molecular weight (Mn) were measured by the method described above, and the (Q) value was calculated.

The polypropylene of the present invention has, besides the above-mentioned characteristics, a crystallinity of 10 measured by an X-ray diffraction method.
% Or more, the intrinsic viscosity [η] measured in tetralin at 135 ° C. is 0.5 to 5 dl / g, particularly preferably 0.7 to 4 dl / g, and the weight average molecular weight (Mw) is 8 or more.
It has additional features of from 10,000 to 1.1 million, particularly preferably from 120,000 to 900,000.

Next, a method for producing the above-mentioned polypropylene of the present invention will be described. The crystalline polypropylene used in the production of the polypropylene of the present invention has a weight average molecular weight (Mw) / number average molecular weight (Mn) value (Q) of 7 to 30 as a measure of the molecular weight distribution from the effect of improving the melt tension.
It is necessary to have a broad molecular weight distribution.
It is a crystalline polypropylene having a crystallinity of 10% or more as measured by an X-ray diffraction method, and preferably has an intrinsic viscosity [η] of 0.5 to 500 measured in tetralin at 135 ° C.
5 dl / g, particularly preferably 0.7 to 4 dl / g is desirable from the viewpoint of moldability. Further, not only propylene homopolymers but also olefins other than propylene, for example, linear monoolefins such as ethylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, and the like,
Branched-chain monoolefins such as 4-methylpentene-1, 2-methylpentene-1 and the like, and random copolymers of styrene and the like with propylene can also be used. When a copolymer is used, the olefin other than propylene is not limited to one type, and two or more olefins may be included. Specifically, propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-hexene-1 copolymer, propylene-octene-1 copolymer, propylene-
4-methylpentene-1 copolymer, propylene-ethylene-butene-1 copolymer, propylene-ethylene-4-
Methylpentene-1 copolymer and the like. At this time,
The number of olefin polymerized units other than propylene in the copolymer is 1
It needs to be 0% by weight or less. If it exceeds 10% by weight, a gel is easily generated in the obtained polypropylene, which is outside the scope of the present invention.

The method for producing crystalline polypropylene having such a wide molecular weight distribution is not particularly limited, and various known methods can be used. For example, a method of mixing two or more crystalline polypropylenes having different molecular weights, a method of polymerizing crystalline polypropylenes having different molecular weights in multiple stages, and a method of polymerizing propylene using a plurality or a specific catalyst component It can be manufactured by a method or the like. At this time, the form in which propylene is polymerized includes slurry polymerization in which propylene is polymerized in an inert solvent, bulk polymerization in which propylene itself is used as a solvent, and gas phase polymerization in which the propylene gas is mainly used in a gas phase, and It can be obtained by a known method combining these.

The form of the crystalline polypropylene used in the present invention is not particularly limited, and may be in the form of powder, pellet, film, sheet, or the like.
From the viewpoint of reaction efficiency and commercial production, the powder in a state immediately after completion of the polymerization step and before pelletization obtained by the above-described various methods is a preferable form. The average particle size of the powder is about 50 μm to 5 mm. It is preferable that the particle size is small in terms of reaction efficiency, but it is preferable that the particle size is large from the viewpoint of powder fluidity. Therefore, it is preferable to use one having a particle size suitable for the purpose.

In the present invention, di-2-ethylhexyl peroxydicarbonate reacted with crystalline polypropylene has a decomposition temperature of 92 ° C. when the half-life is 1 minute and a decomposition temperature when the half-life is 1 hour. It is an organic peroxide exhibiting 60 ° C. The use of similar percarbonates having similar decomposition temperatures does not achieve the objects of the present invention, as will be apparent from the examples below.

When added to and mixed with the crystalline polypropylene, the mixture was diluted with an inert solvent typified by a hydrocarbon solvent such as toluene, xylene, isoparaffin, octane, decane, etc. in order to handle the reaction and to make the reaction uniform. It is convenient to use one. The concentration of di-2-ethylhexyl peroxydicarbonate in the solvent is about 10 to 90% by weight.

The reaction between the crystalline polypropylene and di-2-ethylhexyl peroxydicarbonate in the method of the present invention is carried out by first reacting the crystalline polypropylene with di-2 in an inert gas atmosphere such as nitrogen or argon in a reaction vessel.
-Add and mix ethylhexyl peroxydicarbonate. The temperature at this time is desirably 40 ° C. or less and 0 ° C. or more.
In addition, it is desirable to stir so as to sufficiently mix.
The amount added is 1 per 100 g of crystalline polypropylene.
It is preferably from 10 to 10 mmol, particularly preferably from 2 to 10 mmol. If the amount used is small, the effect of reforming is insufficient,
If the amount is too large, not only the effect cannot be expected to be improved, but also an odor remains, or the polypropylene becomes unstable with great deterioration over time.

The mixed crystalline polypropylene and di-
2-Ethylhexyl peroxydicarbonate is subsequently reacted in an inert gas atmosphere in a reaction vessel, optionally under stirring conditions, at 70-150 ° C., preferably 75-150 ° C.
5 minutes to 5 hours at a temperature of 140 ° C., preferably 10 minutes
Incubate for minutes to 3 hours.

After the reaction, the polypropylene is taken out of the reaction vessel and further melt-kneaded to obtain the polypropylene of the present invention. For the melt kneading, a known melt kneading method is used. For example, using a single-screw extruder, a twin-screw extruder, an extruder combining these and a gear pump, a Brabender, a Banbury mixer, etc.
Melt kneading is performed at a temperature equal to or higher than the melting point of polypropylene for about 10 seconds to 1 hour, preferably for about 20 seconds to 30 minutes. By melt kneading, the crystallization temperature rises significantly, and the characteristics of the polypropylene of the present invention appear. The crystallization temperature in the powder before the melt-kneading is the same as that before the reaction or only slightly increased.

After the melt-kneading, it is usually cut into granules to form pellets, which are used for various molded articles. However, the molded articles can be processed immediately after the melt-kneading. In addition,
After washing with an inert solvent if necessary in a powder state before melt-kneading, it is also possible to dry and then melt-knead.

When melt-kneading, an antioxidant, an ultraviolet absorber, an antistatic agent, a nucleating agent, a lubricant, a flame retardant, an anti-blocking agent, a coloring agent,
Various additives such as inorganic or organic fillers can be blended.

The polypropylene of the present invention can be obtained by the above-mentioned method. However, after completion of the reaction and before the melt-kneading, the reaction product is continuously treated under an inert gas atmosphere under an inert gas atmosphere, if necessary, under a stirring condition. Post-heating at 150 ° C. is a desirable embodiment of the present invention. Processing time is 1
0 minutes to 2 hours, preferably 15 minutes to 1 hour is appropriate. The post-heating treatment increases the reaction efficiency,
In addition to further reducing the odor of the obtained polypropylene, a stabilized polypropylene with little change over time can be obtained.

The desired polypropylene of the present invention is obtained by the above-mentioned method, and the polypropylene must have the above-mentioned characteristics. Unless these characteristics are satisfied, the object of the present invention cannot be achieved.

The thus obtained polypropylene of the present invention has an extremely high melt tension and crystallization temperature, is excellent in rigidity and moldability, and can be recycled after being used again as a molded article after re-melting. Therefore, particularly suitable for hollow molding, foam molding, extrusion molding, but not limited to the molding field, by injection molding, T-die molding, thermoforming, etc., various containers such as hollow containers, films, sheets, pipes, It can be used for various molded products such as fibers.

[0044]

The reaction mechanism for obtaining the polypropylene of the present invention is not known at present, but the radicals generated from di-2-ethylhexyl peroxydicarbonate have some mutual effects on the polypropylene having a broad molecular weight distribution. It is presumed that the action and further melt-kneading exhibit the melting behavior and crystallization behavior characteristic of the polypropylene of the present invention, which are not seen in known polypropylenes.

[0045]

Next, the present invention will be described specifically with reference to examples. Definitions of terms used in Examples and Comparative Examples and measurement methods are as follows. (1) Intrinsic viscosity: [η], measured by the method described above.
(Unit: dl / g) (2) Weight average molecular weight: (Mw), measured by the method described above. (3) Number average molecular weight: (Mn), measured by the method described above. (4) Branching degree index: (g), measured by the method described above. (5) Melt tension: (MS) was measured by the method described above. (Unit: gf) (6) Melting point: (Tm) was measured by the method described above.
(Unit: ° C) (7) Crystallization temperature: (Tc), measured by the method described above. (Unit: ° C) (8) Rigidity: A JIS type test piece was prepared from a polypropylene pellet at a molten resin temperature of 230 ° C and a mold temperature of 50 ° C using an injection molding machine, and the test piece was subjected to a humidity of 50%.
%, At room temperature of 23 ° C. for 72 hours.
The flexural modulus was measured according to 7230. (Unit: k
gf / cm ² )

Example 1 After replacing the reactor equipped with a stirrer with a stirrer with a nitrogen gas, Example 1 in JP-B-59-28573 was used.
The titanium trichloride composition obtained by the method described in the above, and diethyl aluminum chloride in an amount of 3 mol per mol of titanium in the titanium trichloride composition, and p as a third component
-Slurry polymerization of propylene in n-hexane in the presence of hydrogen, a molecular weight controller, using a catalyst in which methyl toluate is combined with 0.8 mole per 1 mole of titanium in the titanium trichloride composition. The intrinsic viscosity [η] was 1.68 dl / g and the weight average molecular weight (Mw) /
10 kg of a propylene homopolymer powder having a number average molecular weight (Mn) value (Q) of 9.5 and an average particle size of 140 μm was added. Then, the operation of evacuating the reactor and supplying nitrogen gas to atmospheric pressure was repeated 10 times, and then di-2-ethylhexyl having a concentration of 70% by weight in toluene solution at 25 ° C. under a nitrogen gas atmosphere with stirring. 0.35 mol of peroxydicarbonate was added and mixed. Subsequently, the temperature in the reactor was increased to 120 ° C., and the reaction was performed at the same temperature for 30 minutes. After the reaction time has elapsed, the temperature in the reactor is further increased by 13
The temperature was raised to 5 ° C., and post-treatment was performed at the same temperature for 30 minutes. After the post-treatment, the reactor was cooled to room temperature, and then opened to obtain polypropylene. When the melting point (Tm) and crystallization temperature (Tc) of the polypropylene were measured, they were 163.7 ° C. and 122.4 ° C., respectively. Subsequently, 0.1 part by weight of tetrakis [methylene-3- (3′-5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane and 100 parts by weight of the obtained polypropylene were used. Calcium phosphate 0.1
Parts by weight were mixed, and the mixture was granulated at 230 ° C. by using an extrusion granulator having a screw diameter of 40 mm to obtain the polypropylene of the present invention as pellets. Various physical properties of the pellets were evaluated and measured. As a result, the crystallinity by X-ray diffraction was 67%, and the weight average molecular weight (Mw) / number average molecular weight (Mn) was 9.8. Other results are shown in Table 1.

Examples 2 and 3 The procedure of Example 1 was repeated, except that the intrinsic viscosity of the polypropylene used for the reaction and the reaction conditions and post-treatment conditions were changed as shown in Table 1. A pellet was obtained.

Comparative Examples 1 to 3 In Examples 1 to 3, granulation was carried out in the same manner as in Example 1 without reacting di-2-ethylhexyl peroxydicarbonate with the propylene homopolymer used for the reaction. A pellet was obtained.

Comparative Example 4 In Example 1, when obtaining polypropylene used as a raw material, 0.01 mol of diethylene glycol dimethyl ether was used as the third component of the catalyst in place of methyl p-toluate for 1 mol of titanium. Propylene was slurry polymerized in the same manner as in Example 1 except that the used catalyst was used and the amount of hydrogen was changed, and the intrinsic viscosity [η] was 1.68 dl / g, and the weight average molecular weight (Mw) /
A propylene homopolymer powder having a number average molecular weight (Mn) value (Q) of 5.6 was obtained. 10 kg of the polypropylene
Was reacted with di-2-ethylhexyl peroxydicarbonate in the same manner as in Example 1 except that was used as a starting polypropylene, followed by granulation to obtain polypropylene pellets.

Examples 1 to 3 and Comparative Examples 1 to 4
Table 1 shows the conditions and results.

[0051]

[Table 1]

Example 4 In Example 1, the polypropylene used in the reaction was the same as Example 1 in JP-A-62-104812.
200 moles of the titanium chloride-supported titanium catalyst component and triethylaluminum obtained by the method described in the above, and 200 moles of diisopropyldimethoxysilane as the third component, and 1 mole of titanium in the titanium catalyst component. Using three continuous polymerization reactors connected in series using a catalyst in which 20 moles were combined, while maintaining different hydrogen concentrations in the gas phase in each polymerization reactor, n-hexane The intrinsic viscosity [η] obtained by continuous multi-stage polymerization of propylene at 1.52 d
1 / g, weight average molecular weight (Mw) / number average molecular weight (M
Polypropylene pellets were obtained in the same manner as in Example 1, except that 10 kg of a propylene homopolymer powder having a value (Q) of n) of 12.4 and an average particle size of 750 μm was used.

Comparative Example 5 In Example 4, granules were obtained in the same manner as in Example 4 without reacting di-2-ethylhexyl peroxydicarbonate with the propylene homopolymer used in the reaction to obtain pellets. .

Comparative Example 6 In Example 4, slurry polymerization of propylene was carried out in the same manner as in Example 4 except that one polymerization vessel was used and the amount of hydrogen was adjusted when obtaining polypropylene used as a raw material. And the intrinsic viscosity [η] is 1.52 dl / g,
A propylene homopolymer powder having a weight average molecular weight (Mw) / number average molecular weight (Mn) value (Q) of 5.0 was obtained. After reacting with di-2-ethylhexyl peroxydicarbonate in the same manner as in Example 4 except that 10 kg of the polypropylene was used as a raw material polypropylene, the mixture was granulated to obtain polypropylene pellets.

Comparative Example 7 In Example 4, the decomposition temperature when the half-life was 1 minute was 85 ° C. and the decomposition temperature when the half-life was 1 hour in place of di-2-ethylhexylperoxydicarbonate. Is 57
The reaction was carried out in the same manner as in Example 4 except that di-3-methoxybutyl peroxydicarbonate, which was at
Post-processing was performed.

Comparative Example 8 In Example 4, the decomposition temperature when the half-life was 1 minute was 93 ° C. and the decomposition temperature when the half-life was 1 hour in place of di-2-ethylhexyl peroxydicarbonate. Is 61
The reaction and post-treatment were carried out in the same manner as in Example 4 except that diisopropyl peroxydicarbonate at a temperature of ° C was used.

Comparative Example 9 In Example 4, the decomposition temperature when the half-life was 1 minute was 112 ° C. and the decomposition temperature when the half-life was 1 hour in place of di-2-ethylhexylperoxydicarbonate. Is 7
The reaction and post-treatment were carried out in the same manner as in Example 4 except that t-butyl peroxypivalate at 3 ° C was used.

Table 2 shows the conditions and results of Example 4 and Comparative Examples 5 to 9 described above.

[0059]

[Table 2]

Example 5 In Example 4, the same catalyst as used in Example 4 was used as the polypropylene used in the reaction, and in the first stage, a high molecular weight polymer was obtained by bulk polymerization, and subsequently, a gas phase was obtained in the same polymerization vessel. An ethylene unit content of 0.2% by weight and an intrinsic viscosity [η] of 1.70 dl / obtained by carrying out copolymerization of propylene and ethylene under polymerization conditions for producing a low molecular weight polymer by polymerization. g, weight average molecular weight (Mw) /
A polypropylene pellet was obtained in the same manner as in Example 4 except that 10 kg of a propylene-ethylene random copolymer powder having a number average molecular weight (Mn) value (Q) of 8.0 and an average particle size of 780 µm was used.

Comparative Example 10 In Example 5, the propylene-ethylene random copolymer used as a raw material was granulated in the same manner as in Example 5 without reacting di-2-ethylhexylperoxydicarbonate with pellets. I got

Comparative Example 11 In Example 5, when obtaining polypropylene used as a raw material, except that bulk polymerization was carried out in one step without performing polymerization in multiple steps, and the amounts of ethylene and hydrogen were adjusted. Was obtained by copolymerizing propylene and ethylene in the same manner as in Example 5, having an ethylene unit content of 0.2% by weight and an intrinsic viscosity [η] of 1.72 d.
1 / g, weight average molecular weight (Mw) / number average molecular weight (M
A propylene-ethylene random copolymer powder having a value (Q) of n) of 4.8 was obtained. 10 kg of the polypropylene
Was reacted with di-2-ethylhexyl peroxydicarbonate in the same manner as in Example 5 except that was used as a starting polypropylene, followed by granulation to obtain polypropylene pellets.

Example 6 In Example 4, the same catalyst as used in Example 4 was used as the polypropylene used in the reaction.
Propylene, ethylene and butene-1 are continuously copolymerized in two stages by gas-phase polymerization while maintaining different hydrogen concentrations in the gas phase in each of the two continuous gas-phase polymerization reactors. The ethylene unit content was 3.2% by weight, butene-1 unit content was 2.5% by weight, the intrinsic viscosity [η] was 1.60 dl / g, and the weight average molecular weight ( Mw) / propylene having a number average molecular weight (Mn) value (Q) of 7.8 and an average particle size of 770 μm.
Ethylene-butene-1 random copolymer powder 10k
g of polypropylene, and the reaction conditions and post-treatment conditions were changed as shown in Table 3 to obtain polypropylene pellets in the same manner as in Example 1.

Comparative Example 12 In Example 6, propylene-ethylene-butene-1 random copolymer used as a raw material was produced in the same manner as in Example 5 without reacting di-2-ethylhexylperoxydicarbonate. Granulated to obtain pellets.

Comparative Example 13 In Example 6, when the polypropylene used as the raw material was obtained, the gas phase polymerization was carried out in one step without performing the polymerization in multiple steps. Except that the concentration was adjusted, the copolymerization of propylene, ethylene and butene-1 was carried out in the same manner as in Example 5 to obtain an ethylene unit content of 3.2% by weight and a butene-1 unit content. Is 2.5% by weight, intrinsic viscosity [η] is 1.60 dl / g, weight average molecular weight (Mw) /
A propylene-ethylene-butene-1 random copolymer powder having a number average molecular weight (Mn) value (Q) of 4.1 was obtained. After reacting with di-2-ethylhexyl peroxydicarbonate in the same manner as in Example 6 except that 10 kg of the polypropylene was used as a raw material polypropylene, the mixture was granulated to obtain polypropylene pellets.

Examples 5 and 6 and Comparative Examples 10 to 1
Table 3 shows the conditions and results of No. 3.

[0067]

[Table 3]

Example 7 Tetrakis [methylene-3- (3′-5 ′) was added to 100 parts by weight of a polypropylene powder obtained by reacting di-2-ethylhexyl peroxydicarbonate with the starting polypropylene in the same manner as in Example 1. -Di-t-butyl-4 '
-Hydroxyphenyl) propionate] methane 0.1
Parts by weight, 0.1 part by weight of calcium stearate, and 0.1 part by weight of talc as a foam nucleating agent were mixed, and the mixture was supplied to a single screw extruder set to a screw diameter of 65 mm and an extruder temperature of 230 ° C. Then, 22 parts by weight of 1,1,2,2-tetrafluorodichloroethane was injected as a foaming agent in the middle of the extruder. Attached to the extruder,
Using a nozzle-shaped mold with a diameter of 5 mm, mold temperature 155 ° C
Extrusion foam molding was carried out. The surface of the obtained foam was smooth, and there were no abnormal air bubbles and uniform air bubbles.

Comparative Example 14 In Example 7, the polypropylene powder obtained by reacting di-2-ethylhexyl peroxydicarbonate was replaced with the propylene homopolymer used as a raw material in obtaining the polypropylene powder. Except for the above, extrusion foaming was carried out in the same manner. As a result, the foam obtained was poor in appearance due to outgassing, and had large nests, and could not be used.

Example 8 The propylene-ethylene random copolymer pellets obtained in the same manner as in Example 5 were subjected to extrusion sheeting at 260 ° C. using an extruder having a T-die and a screw diameter of 65 mm. And a sheet having a thickness of 0.5 mm. Next, in order to modelly evaluate the heat vacuum formability of the sheet, the sheet was fixed to a 40 cm square frame at 210 ° C.
And the behavior was observed. By heating, the center of the sheet begins to sag, and when the sheet sags 31 mm,
The droop stopped, and the droop rose. After drooping stop 20
After a lapse of seconds, the sheet began to sag again, and thereafter only sagged. The amount of droop was small and the time until the start of re-droop was as long as 20 seconds, indicating that the sheet was extremely excellent in heat vacuum formability.

Comparative Example 15 In Example 8, instead of the polypropylene of the present invention,
A sheet was obtained in the same manner except that pellets of the propylene-ethylene random copolymer obtained in the same manner as in Comparative Example 11 were used. When the heating behavior of the sheet was observed in the same manner as in Example 8, the suspension stopped for 40 m.
m, and the time until the start of re-drooping was as short as 8 seconds, and the heating vacuum formability was inferior to Example 8 above.

Example 9 In order to recycle the molded article of the present invention, a large number of test pieces for measuring the flexural modulus were prepared in the same manner as in Example 1.
A polypropylene composition comprising 10% by weight of a pulverized test piece obtained by subjecting the injection molded test piece to a pulverizer and 90% by weight of a polypropylene pellet obtained in the same manner as in Example 1 was directly blown with a screw diameter of 65 mm. Using a molding machine, at a molding temperature of 230 ° C, a mold temperature of 20 ° C, a kerosene tank with an inner volume of 100 l was hollow-molded.
As for the parison, a uniform hollow molded product without unevenness in thickness was obtained without drawdown.

Comparative Example 16 A hollow molding was performed in the same manner as in Example 9 except that polypropylene pellets obtained in the same manner as in Comparative Example 1 were used. The hollow molding could not be performed.

Comparative Example 17 In Example 9, except that the polypropylene pellets obtained in the same manner as in Comparative Example 4 were used as the polypropylene, hollow molding was performed in the same manner as in Example 8, and the parison was drawn down. This resulted in a non-uniform hollow molded product with uneven thickness.

[0075]

As is clear from the above Examples and Comparative Examples, the polypropylene of the present invention has an extremely high melt tension and crystallization temperature, is excellent in rigidity and moldability, and is limited by conventional polypropylene. It is possible to expand the field of use.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) C08F 10/00-10/14 C08F 110/00-110/14 C08F 210/00-210/18 C08F 8 / 00-8/50 CA (STN)

Claims (10)

(57) [Claims] 1. A linear crystalline polypropylene having a degree of branching index of substantially 1 and (A) a melt tension (MS) at 230 ° C. and an intrinsic viscosity measured in tetralin at 135 ° C. [ η] and log (MS)> 4.24 × log [η] −0.685, and (B) crystallization temperature (Tc) and melting point measured by a differential scanning calorimeter (DSC). (Tm) satisfies the relationship of (Tc)> 0.784 × (Tm) −4.00, (C) the boiling xylene extraction residual ratio is 1% by weight or less, and (D) the weight average molecular weight ( Mw) / number average molecular weight (Mn)
Wherein the value (Q) is 7 to 30. 2. The polypropylene according to claim 1, wherein the crystalline polypropylene is a propylene homopolymer. 3. The polypropylene according to claim 1, wherein the crystalline polypropylene is a propylene-olefin random copolymer containing 10% by weight or less of olefin polymerization units other than propylene. 4. In an inert gas atmosphere, the value (Q) of weight average molecular weight (Mw) / number average molecular weight (Mn) is 7
100 g of linear crystalline polypropylene of
1 to 10 mmol of di-2-ethylhexyl peroxydicarbonate, mixed and reacted under a temperature condition of 70 to 150 ° C. for 10 minutes to 3 hours, and then melt-kneaded. A linear crystalline polypropylene having an index of substantially 1, and (A) a melt tension (MS) at 230 ° C. and an intrinsic viscosity [η] measured at 135 ° C. in tetralin are represented by log ( MS)> 4.24 × log [η] −0.685, and (B) the crystallization temperature (Tc) and the melting point (Tm) measured by a differential scanning calorimeter (DSC) are as follows: Tc)> 0.784 × (Tm) −4.00 is satisfied, (C) boiling xylene extraction residual ratio is 1% by weight or less, and (D) weight average molecular weight (Mw) / number average molecular weight ( Mn)
A method for producing a polypropylene having a value (Q) of 7 to 30. 5. The method according to claim 4, wherein the crystalline polypropylene is a propylene homopolymer. 6. The method according to claim 4, wherein the crystalline polypropylene is a propylene-olefin random copolymer containing 10% by weight or less of olefin polymerized units other than propylene. 7. After the reaction of the crystalline polypropylene with di-2-ethylhexyl peroxydicarbonate, it is followed by a post-heating treatment under an inert gas atmosphere at 100 to 150 ° C. for 10 minutes to 3 hours. Item 5. The method according to Item 4. 8. A linear crystalline polypropylene having a branching index of substantially 1 and (A) a melt tension (MS) at 230 ° C. and an intrinsic viscosity measured at 135 ° C. in tetralin [ η] and log (MS)> 4.24 × log [η] −0.685, and (B) crystallization temperature (Tc) and melting point measured by a differential scanning calorimeter (DSC). (Tm) satisfies the relationship of (Tc)> 0.784 × (Tm) −4.00, (C) the boiling xylene extraction residual ratio is 1% by weight or less, and (D) the weight average molecular weight ( Mw) / number average molecular weight (Mn)
A molded article using polypropylene having a value (Q) of 7 to 30. 9. The molded article according to claim 8, wherein the crystalline polypropylene is a propylene homopolymer. 10. The crystalline polypropylene is a propylene-olefin random copolymer containing not more than 10% by weight of olefin polymerized units other than propylene.
The molded article according to the above.