JPH07286020A - Propylene/ethylene block copolymer and crystalline propylene polymer composition - Google Patents

Abstract

PURPOSE:To provide a propylene lethylene block copolymer and a crystalline propylene polymer composition improved in transparency and whitening resistance without detriment to their excellent rigidity, impact resistance, heat resistance and moldability. CONSTITUTION:This block copolymer is one containing 95.0-70.0 pts.wt. crystalline propylene polymer part and 5.0-30.0 pts.wt. ethylene/propylene copolymer part, and this composition is the one comprising 95.0-70.0 pts.wt. crystalline propylene polymer and 5.0-30.0 pts.wt. above block copolymer. These copolymer and composition each has the following properties: an ethylene content of 3-22wt.%, an MFR of 0.3-100g/10min, a cold-xylene-soluble of 2.5-20.0wt.%, an ethylene content of the portion soluble in cold xylene and insoluble in acetone of 40-80wt.%, an [eta]CXIS/[eta]CXS ratio of 0.4-3.0 (wherein [eta]CXIS is the intrinsic viscosity of the cold-xylene-insolubles, and [eta]CXS is the intrinsic viscosity of the cold-xylene-solubles, and appearance of a small melting peak at 118-130 deg.C.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a propylene-ethylene block copolymer and a crystalline propylene polymer composition which are excellent in rigidity, impact resistance, heat resistance and moldability, as well as transparency and whitening resistance.

[0002]

2. Description of the Related Art Polypropylene is lightweight and excellent in rigidity, heat resistance, etc.
It is widely used in various fields such as daily necessities, automobile parts and electric parts. However, since the propylene homopolymer has low impact resistance, it was unsuitable for applications subject to strong impact.

A so-called propylene-ethylene block copolymer composed of a crystalline propylene polymer and an ethylene-propylene copolymer is known as one having improved impact resistance of such a propylene homopolymer.

Although the above propylene-ethylene block copolymer has remarkably improved impact resistance, it has a problem that the transparency of the propylene homopolymer is impaired and the impacted part is whitened.

Further, so-called propylene random polymers in which propylene and a small amount of ethylene are copolymerized are known for the purpose of increasing transparency, and these random polymers are superior to propylene homopolymers. There are drawbacks such as loss of heat resistance and high rigidity, and insufficient improvement of impact resistance at low temperatures.

In order to solve such a problem, Japanese Patent Laid-Open No.
-24995, 61-264012, 61-271315, 63-159412, 63-168414, JP-A
The 4-202409 publication discloses a specific propylene-ethylene block copolymer, but these are all
The balance of rigidity, impact resistance, moldability, transparency, and whitening resistance is still insufficient. Further, a method of carrying out the copolymerization in two steps in producing the propylene-ethylene block copolymer is disclosed in, for example, JP-A-54-139693 and JP-A-55-16048.
JP-A-56-32516 and JP-A-56-55416, the balance of the physical properties of the block copolymer obtained is still not sufficient even with such a method. .

Therefore, the present invention provides the excellent rigidity, impact resistance, and resistance of conventional propylene-ethylene block copolymers.
An object of the present invention is to provide a propylene-ethylene block copolymer and a crystalline propylene polymer composition having improved transparency and whitening resistance while maintaining heat resistance and moldability.

[0008]

Means for Solving the Problems As a result of intensive studies in view of the above-mentioned objects, the present inventors have found that the cause of deteriorating the transparency of a propylene-ethylene block copolymer is a matrix made of crystalline polypropylene, It was found that the incident light was scattered at the interface with the ethylene-propylene copolymer dispersed therein, and the propylene-ethylene block copolymer and composition in which this phenomenon was suppressed, that is, the present invention was obtained. It was

The present invention first comprises (A) 95.0 to 70.0 parts by weight of crystalline propylene polymer moieties and (B) 5.0 to 30.0 parts by weight of ethylene-propylene copolymer moieties. A propylene-ethylene block copolymer,
(i) an ethylene content of 3 to 22% by weight, (ii) a melt flow rate of 0.3 to 100 g / 10 minutes, (ii)
i) the amount of cold xylene solubles is 2.5 to 20.0% by weight, (iv) the ethylene content of the portion soluble in cold xylene and insoluble in acetone is 40 to 80% by weight, (v) The ratio of the intrinsic viscosity [η] CXIS of the part insoluble in cold xylene to the intrinsic viscosity [η] CXS of the part soluble in cold xylene, [η] CXIS
/ [Η] CXS is 0.4 to 2.0, and (vi) 118
It is a propylene-ethylene block copolymer characterized by having a minute melting peak at ℃ to 130 ℃. Preferred embodiments include the following: (A) Crystalline propylene polymer portion 90.0-75.0
The propylene-ethylene block copolymer as described above, wherein the ethylene-propylene copolymer portion (B) is contained in an amount of 10.0 to 25.0 parts by weight based on parts by weight. The propylene-ethylene block copolymer according to any one of the above, having an ethylene content of 7 to 20% by weight. The propylene-ethylene block copolymer according to any one of the above, having an MFR of 0.4 to 80 g / 10 minutes. The propylene-ethylene block copolymer as described in any one of the above, wherein the amount of cold xylene solubles is 5.0 to 17.5% by weight. The propylene-ethylene block copolymer according to any one of the above, wherein the ethylene content of the portion soluble in cold xylene and insoluble in acetone is 40 to 60% by weight. [Η] CXIS / [η] CXS is 0.6 to 1.8, and the propylene-ethylene block copolymer according to any one of the above. The propylene-ethylene block copolymer according to any one of the above, having a minute melting peak at 124 to 129 ° C.

The present invention secondly comprises 95.0 to 70.0 parts by weight of (A ') crystalline propylene polymer and 5.0 to 30.0 parts by weight of (B') ethylene-propylene copolymer. 1. a composition having (i) an ethylene content of 3 to 22% by weight, (ii) a melt flow rate of 0.3 to 100 g / 10 minutes, and (iii) a cold xylene soluble content of 2. 5-20.0
% By weight, (iv) the ethylene content of the portion soluble in cold xylene and insoluble in acetone is 40 to 80% by weight,
(v) Intrinsic viscosity [η] CXIS of the part insoluble in cold xylene,
The ratio of the intrinsic viscosity [η] CXS of the part soluble in cold xylene,
[Η] CXIS / [η] CXS is 0.4 to 2.0, and
(vi) A crystalline propylene polymer composition having a minute melting peak at 118 ° C to 130 ° C. Preferred embodiments include the following: '(A') crystalline propylene polymer 90.0 to 75.0 parts by weight of (B ') ethylene-propylene copolymer 1
The crystalline propylene polymer composition as described above, which is contained in an amount of 0.0 to 25.0 parts by weight. 'The crystalline propylene polymer composition according to any one of the above, wherein the ethylene content is 7 to 20% by weight. The crystalline propylene polymer composition as described in any one of the above, wherein the MFR is 0.4 to 80 g / 10 minutes. 'The crystalline propylene polymer composition according to any one of the above, wherein the amount of cold xylene solubles is 5.0 to 17.5% by weight. 'The crystalline propylene polymer composition according to any one of the above, wherein the ethylene content of the portion soluble in cold xylene and insoluble in acetone is 40 to 60% by weight. '[Eta] CXIS / [eta] CXS is 0.6-1.8, The crystalline propylene polymer composition in any one of the above. The crystalline propylene polymer composition as described in any one of the above, which has a minute melting peak at '124 to 129 ° C.

First, the first invention, that is, the propylene-ethylene block copolymer will be described. This copolymer comprises (A) a crystalline propylene polymer portion and (B) an ethylene-propylene copolymer portion, and (A) portion 95.0-
70.0 parts by weight of the (B) part 5.0 to 30.0 parts by weight, preferably (A) part 90.0 to 75.0 parts by weight of the (B) part 10.0 to 25. Included in a ratio of 0 parts by weight.

Examples of the crystalline propylene polymer (A) constituting the crystalline propylene polymer portion include a propylene homopolymer and a random copolymer of propylene and a small amount of ethylene. In this case, the propylene content is 9
It is preferably 5% by weight or more. In addition, comonomer components other than ethylene, such as butene-1, octene-1 and other α
-Although an olefin or a diene-based monomer may be further contained, the propylene content is preferably 95% by weight or more in this case as well.

(B) The ethylene-propylene copolymer constituting the ethylene-propylene copolymer part preferably contains ethylene in an amount of 65 to 90% by weight, more preferably 70 to 8% by weight.
It is included in a ratio of 5% by weight. This copolymer has a third component such as butene-1, octene-1 and the like α-other than ethylene.
It may further contain an olefin or a diene-based monomer. In that case, the content of these third components is preferably 2% by weight or less. The ethylene content of the whole copolymer of the present invention is 3 to 22% by weight, preferably 7 to 20% by weight, more preferably 12 to 18% by weight. When the ethylene content is lower than the above range, the impact strength is lowered, and when the ethylene content is higher than the above range, the transparency is deteriorated. The ethylene content can be measured by a known means such as an infrared absorptiometry (IR method).

The melt flow rate (MFR) in the copolymer of the present invention is 0.3 to 100 g / 10 minutes, preferably 0.4 to 80 g / 10 minutes, more preferably 0.5 to 60 minutes.
It is g / 10 minutes. When the melt flow rate is lower than the above range, the moldability becomes poor, and when the melt flow rate is higher than the above range, the impact strength decreases. MFR is ASTMD
It is measured according to 1238.

The amount of cold xylene solubles in the copolymer of the present invention is 2.5 to 20.0% by weight, preferably 5.0 to
It is 17.5% by weight, more preferably 7.5 to 15.0% by weight. When the amount of cold xylene solubles is below the above range, impact resistance is lowered, and when above the above range, rigidity and heat resistance are lowered. In the present invention, the amount of cold xylene solubles was measured by the following method. That is, add 2 g of the sample to 200 ml of xylene,
Dissolve by heating at ℃. This is left to cool to 23 ° C. and left for 15 hours, and then the dissolved portion and the precipitated portion are separated by filtration. After the solvent is removed from the dissolved portion (component soluble in cold xylene) by evaporation, the weight is weighed. The weight ratio (% by weight) of the above-mentioned dissolved components to the whole sample is defined as the cold xylene soluble content. However, when the sample contains an optional component such as a filler, it is removed by an operation such as hot filtration in advance, and the weight ratio of the cold xylene-dissolved component to the portion excluding the component such as the filler from the sample is adjusted. Ask.

In the copolymer of the present invention, the ethylene content of the portion which is soluble in cold xylene and insoluble in acetone is 4
It is 0 to 80% by weight, preferably 40 to 60% by weight, and more preferably 40 to 50% by weight. When the ethylene content is lower than the above range, the transparency is significantly deteriorated and the rigidity is slightly lowered, and when the ethylene content is higher than the above range, the impact resistance is lowered. In the present invention, such ethylene content was measured by the following method. That is,
2 g of the sample is added to 200 ml of xylene and dissolved by heating at 140 ° C. This is left to cool to 23 ° C. and left for 15 hours, and then the dissolved portion and the precipitated portion are separated by filtration. The dissolved portion (a component soluble in cold xylene) is collected, and this solution is put into 10 times the amount of acetone, and after stirring, the precipitated portion is collected by filtration. The solvent is evaporated off from the precipitated portion, thus obtaining a portion soluble in cold xylene and insoluble in acetone.
For this, the ethylene content is measured by a known means such as an infrared absorptiometry (IR method).

In the copolymer of the present invention, the intrinsic viscosity of a portion insoluble in cold xylene (this is referred to as [η] CXIS)
And the intrinsic viscosity of the part soluble in cold xylene (this is [η]
([CXS]), that is, [η] CXIS / [η] CX
S is 0.4 to 2.0, preferably 0.6 to 1.8, and more preferably 0.8 to 1.6. When this ratio is below the above range, the transparency is deteriorated, and when it is above the above range, the impact resistance is deteriorated. In the present invention,
[Η] CXIS / [η] CXS was obtained by the following method.
That is, add 2 g of sample to 200 ml of xylene and add 1
Dissolve by heating at 40 ° C. Allow it to cool to 23 ° C, 15
After standing for a while, the dissolved portion and the deposited portion are separated by filtration. The solvent of each of the dissolved portion (soluble in cold xylene) and the precipitated portion (insoluble in cold xylene) is removed by evaporation, and each portion is recovered separately. However, when the sample contains an arbitrary component such as a filler, the one removed by an operation such as hot filtration in advance is used. The intrinsic viscosity of each part, that is, [η] CXS and [η] CXIS, is measured in decalin at 135 ° C., and then the ratio [η] CXIS / [η] CXS of both is obtained.

The copolymer of the present invention has a temperature of 118 ° C to 130 ° C.
And preferably has a fine melting peak at 124 to 129 ° C. If it has a fine melting peak in the temperature range below the above range, or if it has no fine melting peak at all, the transparency is poor, and if it has a fine melting peak in the temperature range above the above range, it is resistant. In addition to the impact resistance being lowered, the transparency may be deteriorated in some cases. In the present invention, the melting peak is
It measured using the differential scanning calorimeter (DSC). The measurement conditions of DSC are as follows. First, a sample pan containing 10 mg of a sample is heated in a DSC heating furnace to 230 ° C. and left for about 15 minutes to melt it. After that, 10 ° C /
The temperature is lowered to 50 ° C. at a cooling rate of minutes to crystallize. Finally, the temperature is raised to 200 ° C at a rate of 10 ° C / min and the melting pattern of the sample is recorded. From this melting pattern, the temperature of the fine melting peak is determined. Usually, a crystalline propylene homopolymer is at 160 to 180 ° C., and a so-called random copolymer obtained by copolymerizing propylene and a small amount of ethylene is 13
A major melting peak occurs at 5 to 155 ° C., but in the block copolymer of the present invention (or the composition of the present invention), 1
The minute melting peak at 18 ° C. to 130 ° C. is generated by overlapping these main melting peaks, and the entire block copolymer of the present invention (or the composition of the present invention) has only a minute peak. is not. The size of the minute peak is usually about ⅕ or less of the main melting peak.

In the present invention, the same method was used in the following method for measuring each of the above characteristics.

Such a copolymer is produced, for example, by producing a crystalline propylene polymer portion in one or more steps of a conventional propylene polymerization method and subsequently producing an ethylene-propylene copolymer portion in one or more steps. Can be obtained by At that time, the copolymer having the above-mentioned properties according to the present invention can be obtained by specifying the reaction conditions. For example, in the process of producing the crystalline propylene polymer portion, the reaction temperature is -80 to 150 ° C, preferably 40 to
At 120 ° C., a crystalline propylene polymer having an MFR of 0.3 to 120 g / 10 min was added to 70 to 95% of the total polymer by a conventional method using hydrogen or another known molecular weight regulator.
After synthesizing so as to be wt%, in the presence thereof,
Propylene and ethylene are supplied at a ratio of propylene: ethylene (weight ratio) of 50:50 to 10:90 and copolymerized to 30 to 5% by weight of the total polymer. At this time, hydrogen or another known molecular weight modifier can be used to achieve the desired cold xylene insoluble content, soluble content and its intrinsic viscosity ratio.

The copolymer of the present invention may further contain polyethylene and the like, in addition to the above-mentioned components (A) and (B), as long as the object of the present invention is not impaired.

Further, the copolymer of the present invention can be used as a composition containing a conventional additive together. Examples of conventional additives include antioxidants, heat stabilizers, light stabilizers, flame retardants, plasticizers, antistatic agents, lubricants, release agents, nucleating agents, and fillers. However, the nucleating agent is effective in further improving the transparency of the composition, and among them, the dibenzylidene sorbitol derivative is preferable.

The present invention secondly provides a composition comprising (A ') a crystalline propylene polymer and (B') an ethylene-propylene copolymer. The blending ratio of (A ') and (B') is (A ') 9
5.0 to 70.0 parts by weight (B ') 5.0 to 30.0
The amount of (B ') is 10.0 to 25.0 parts by weight, preferably 90.0 to 75.0 parts by weight of (A').

As the crystalline propylene polymer (A '), the same crystalline propylene polymer as used in the above-mentioned propylene-ethylene block copolymer can be used. That is, in addition to the propylene homopolymer, a random copolymer containing ethylene or another α-olefin, a diene monomer or the like can be used. The propylene content is preferably 95% by weight or more.

The ethylene-propylene copolymer (B ') contains ethylene in an amount of preferably 65 to 90% by weight, more preferably 75 to 85% by weight. The copolymer may further contain, as a third component, an α-olefin other than ethylene such as butene-1 and octene-1 and a diene monomer. In that case, the content of these third components is preferably 2% by weight or less.

The composition of the present invention can contain, in addition to the above-mentioned components (A ') and (B'), the propylene-ethylene block copolymer detailed above.

The ethylene content in the composition of the present invention is
It is 3 to 22% by weight, preferably 7 to 20% by weight, more preferably 12 to 18% by weight. When the ethylene content is below the above range, the impact strength is lowered, and when it is above the above range, the transparency is deteriorated.

The melt flow rate (MFR) in the composition of the present invention is 0.3 to 100 g / 10 minutes, preferably 0.4 to 80 g / 10 minutes, more preferably 0.5 to 60 g.
/ 10 minutes. When the melt flow rate is below the above range, moldability becomes poor, and when it is above the above range, the impact strength decreases.

The amount of cold xylene solubles in the composition of the present invention is 2.5 to 20.0% by weight, preferably 5.0 to 1.
7.5% by weight, more preferably 7.5-15.0% by weight
Is. When the amount of cold xylene solubles is below the above range, impact resistance is lowered, and when above the above range, rigidity and heat resistance are lowered.

In the composition of the present invention, the ethylene content of the portion soluble in cold xylene and insoluble in acetone is 40.
-80% by weight, preferably 40-60% by weight, more preferably 40-50% by weight. When the ethylene content is lower than the above range, the transparency is significantly deteriorated and the rigidity is slightly lowered, and when the ethylene content is higher than the above range, the impact resistance is lowered.

In the composition of the present invention, the ratio of the intrinsic viscosity of the portion insoluble in cold xylene ([η] CXIS) to the intrinsic viscosity of the portion soluble in cold xylene ([η] CXS), that is, [[ η] CXIS / [η] CXS is 0.4 to 2.0, preferably 0.6 to 1.8, and more preferably 0.8 to 1.6. When this ratio is below the above range, the transparency is deteriorated, and when it is above the above range, the impact resistance is deteriorated.

The composition of the present invention has a temperature of 118 ° C to 130 ° C.
And preferably has a fine melting peak at 124 to 129 ° C. If it has a fine melting peak in the temperature range below the above range, or if it has no fine melting peak at all, the transparency is poor, and if it has a fine melting peak in the temperature range above the above range, it is resistant. In addition to the impact resistance being lowered, the transparency may be deteriorated in some cases.

Such a composition has, for example, a specific (A ')
The crystalline propylene polymer and the (B ′) ethylene-propylene copolymer can be produced separately, and then both (and optional components) are blended at a predetermined ratio and melt-kneaded. (A ') crystalline propylene polymer and (B')
As the ethylene-propylene copolymer, those produced by a conventional method can be used. The apparatus, conditions, etc. used in the melt-kneading are known to those skilled in the art.

Such a specific combination of (A ') and (B') is, for example, (A ') produced by a conventional method,
Or using a commercially available crystalline propylene polymer having an MFR of 0.3 to 120 g / 10 min, and
(B ') has a MFR of 0.001 to 100 g / 10 min produced by copolymerizing propylene and ethylene, has an ethylene content of 65 to 90% by weight, and 118 to 130 ° C.
By selecting an ethylene-propylene copolymer having a very small melting peak, a composition having the above characteristics can be obtained. Such (B ') is known per se and can be produced according to the method disclosed in, for example, JP-A-62-295906.

In the composition of the present invention, in addition to the above-mentioned components, other resins such as polyethylene can be blended within a range not impairing the object of the present invention, and an antioxidant,
Various additives such as a heat stabilizer, a light stabilizer, a flame retardant, a plasticizer, an antistatic agent, a lubricant, a release agent, a nucleating agent and a filler can be added. Among the above additives, the nucleating agent is effective in further improving the transparency of the composition, and among them, the dibenzylidene sorbitol derivative is preferable.

[0036]

The reason why the crystalline propylene-ethylene block copolymer and the crystalline propylene polymer composition of the present invention exhibit excellent transparency while maintaining good mechanical properties is not clear. The polymer or composition has a small difference in refractive index between the crystalline propylene polymer matrix and the ethylene-propylene copolymer portion, as compared to conventionally known propylene-ethylene block copolymers and propylene polymer compositions, As a result, it is speculated that this is probably because light scattering at the interface between the two phases was suppressed.

[0037]

EXAMPLES Production Example 1 (Production of polymerization catalyst) In a 1 liter reaction vessel having a reflux condenser, under a nitrogen gas atmosphere, chip-shaped metallic magnesium (purity: 99.5
%, Average particle size 1.6 mm) 8.3 g and n-hexane 250
After adding 1 ml and stirring at 68 ° C. for 1 hour, metallic magnesium was taken out and dried under reduced pressure at 65 ° C. to obtain pre-activated metallic magnesium.

Next, 140 ml of n-butyl ether and n-butyl ether solution of n-butyl magnesium chloride (1.75 mol / liter) were added to this magnesium metal.
0.5 ml was added and stirred to give a suspension, which was kept at 55 ° C. In addition to this, n-butyl ether 50
A solution in which 38.5 ml of n-butyl chloride was dissolved in ml was added dropwise over 50 minutes. Then, while stirring, 70
After carrying out the reaction at 4 ° C for 4 hours, the reaction solution was kept at 25 ° C.

Next, to this reaction solution, HC (OC ₂ H ₅ ) was added.
₃ 55.7 ml was added dropwise over 1 hour, and after completion of the addition, 60
The reaction was carried out at 15 ° C for 15 minutes, and the obtained reaction product solid was washed 6 times with 300 ml each of n-hexane. Then at room temperature 1
After drying under reduced pressure over time, 31.6 g of a magnesium-containing solid containing 19.0% by weight of magnesium and 28.9% by weight of chlorine was obtained.

Into a 300 ml reaction vessel equipped with a reflux condenser, a stirrer and a dropping funnel, 6.3 g of the magnesium-containing solid obtained above and 50 ml of n-heptane were charged under a nitrogen gas atmosphere and stirred. As a suspension, a mixture of 20 ml (0.02 mmol) of 2,2,2-trichloroethanol and 11 ml of n-heptane is added dropwise to this suspension in a dropping funnel over 30 minutes while stirring at room temperature. And then 80
Stir at 1 ° C for 1 hour. The suspension was filtered, and the obtained solid was washed 4 times with 100 ml of room temperature n-hexane each time and twice with 100 ml each of toluene to obtain a solid component (solid component A).

To the solid component A thus obtained, 40 ml of toluene was added, and titanium tetrachloride was further added at a ratio such that titanium tetrachloride / toluene (volume ratio) was 3/2, and 90 ° C. The temperature was raised to. Next, a mixture of 2 ml of di-n-butyl phthalate and 5 ml of toluene was added dropwise to this mixture over 5 minutes while stirring, and then the mixture was stirred at 120 ° C. for 2 hours. The solid substance was obtained by filtering this mixed liquid at 90 degreeC. This solid material was heated at 90 ° C to 100 m of toluene each.
Wash twice with l. Furthermore, the same amounts of titanium tetrachloride and toluene as before were added, and the mixture was stirred at 120 ° C. for 2 hours. The solid substance was obtained by filtering this mixed liquid at 110 degreeC. The solid material was washed 7 times with 100 ml of n-hexane each at room temperature. Thus, 5.5 g of the polymerization catalyst was obtained. Example 1 Synthesis of Propylene-Ethylene Block Copolymer (1) Preparation for Polymerization 27.7 mg of the polymerization catalyst obtained in Production Example 1 and 4 ml of a solution containing 0.3 mol of triethylaluminum in 1 liter of n-heptane. And 0.08 in 1 liter of n-heptane
A solution containing 3 moles of diphenyldimethoxysilane 3 m
What was mixed for 1 minute and kept for 5 minutes was put into a 5 liter autoclave that had been purged with nitrogen and sufficiently dried. (2) Manufacture of propylene homopolymer part Into this autoclave, 13.0 liters of hydrogen and 3 liters of liquid propylene were press-fitted, the internal temperature of the autoclave was raised to 70 ° C., and polymerization was carried out for 1 hour to crystallize A propylene polymer was obtained. After the polymerization was completed, unreacted propylene and hydrogen were purged, and the pressure in the autoclave was adjusted to 0.2 kg / cm ² · G. (3) Production of ethylene-propylene copolymer part Next, 4.0 liters of hydrogen gas was introduced into the system. Subsequently, the internal temperature of the autoclave was raised to 75 ° C., and a mixed gas of propylene and ethylene (propylene: ethylene (weight ratio) = 28: 72) was used to adjust the monomer partial pressure to 6 kg / cm ^2.
-Supplying while maintaining at G, the polymerization reaction was carried out for about 2.5 hours until the fraction of the ethylene-propylene copolymer became 20% by weight. After the polymerization was completed, the unreacted gas was purged to obtain a white powdery propylene-ethylene block copolymer. (4) Analysis of the Block Copolymer Obtained The propylene-ethylene block copolymer thus obtained was analyzed based on the weight change at each reaction step, and 80.0 parts by weight of the propylene homopolymer block and the ethylene-propylene random copolymer were used. It was a block copolymer consisting of 20.0 parts by weight of polymer block. As a result of ¹³ C-NMR measurement, it was found that the ethylene content in the ethylene-propylene random copolymer was 80.0% by weight. Further, the MFR of this copolymer, the ethylene content of the entire copolymer, DSC, the amount of cold xylene solubles, the intrinsic viscosity ratio between the cold xylene insoluble part and the soluble part, and the ethylene content of the cold xylene soluble acetone insoluble part were measured. . The results are shown in Table 1. The results of haze measurement are also shown in Table 1. Further, the flexural modulus and the DuPont impact strength were measured, and the results are shown in Table 1.

The physical properties of the sample powder are 2,6-di-t-
Butyl-4-methylphenol 0.18% by weight, distearyl thiodipropionate 0.08% by weight, tetrakis {methylene- (3,5-di-t-butyl-4-hydroxyhydrocinnamate)} methane Was added by 0.04% by weight and calcium stearate by 0.06% by weight, and the mixture was melt-kneaded to form pellets, which were then injection-molded to prepare test pieces, which were used.

The haze (a measure of transparency) is 60 × injection-molded at a cylinder temperature of 250 ° C. and a mold temperature of 60 ° C.
A 60 × 1 mm test piece was used for measurement in accordance with JIS K7105-1981. Flexural modulus was measured according to JIS K7203-1982, and DuPont impact strength (-20 ° C, 1 mm) was measured according to JIS K7211-1976.
It was measured according to. Examples 2 to 4 and Comparative Examples 1 to 4 Synthesis of Propylene-Ethylene Block Copolymers Hydrogen supply in step (2) of Example 1 and hydrogen, propylene and ethylene supply amounts in step (3) and copolymerization time are shown. A propylene-ethylene block copolymer was produced in the same manner as in Example 1 except that it was changed as shown in 2. MFR, ethylene content, DS of this copolymer
Table 1 shows C, the amount of cold xylene solubles, the intrinsic viscosity ratio between the cold xylene insoluble part and the soluble part, and the ethylene content of the cold xylene soluble acetone insoluble part. Table 1 also shows the results of haze measurement, bending elastic modulus, and DuPont impact strength of the test pieces injection-molded in the same manner as in Example 1. Example 5 Production of crystalline propylene polymer composition In the same manner as in step (1) of Example 1, an autoclave was used to prepare a polymerization catalyst, an n-heptane solution containing triethylaluminum and an n-heptane solution containing diphenyldimethoxysilane. After adding the mixture consisting of 300 g, 300 g of dried calcium chloride was further added thereto, and the mixture was stirred for 30 minutes.

Hydrogen gas and a mixed gas of propylene and ethylene were supplied to this under the same conditions as in step (3) of Example 1 to produce an ethylene-propylene copolymer. After the completion of the polymerization, unreacted gas was purged, and the product was washed with water to remove calcium chloride to obtain an ethylene-propylene random copolymer. The ethylene content of this copolymer is 7
It was 9.9% by weight.

20 parts by weight of the thus obtained ethylene-propylene copolymer and 80 parts by weight of propylene homopolymer (manufactured by Tonen Chemical Co., Ltd., grade name: Tonen Polypro J240F) are melted at 230 ° C. in an extruder. The mixture was kneaded to obtain a crystalline propylene polymer composition. Physical properties of this were measured in the same manner as in Example 1, and the results are shown in Table 1. Comparative Example 5 Production of crystalline propylene polymer composition Example except that ethylene-propylene rubber (manufactured by Nippon Synthetic Rubber Co., Ltd., grade name: EPO7P) was used in place of the ethylene-propylene copolymer of Example 5. A crystalline propylene polymer composition was obtained in the same manner as in 5. Physical properties of this were measured in the same manner as in Example 1, and the results are shown in Table 1.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

According to the present invention, propylene having improved transparency and whitening resistance while maintaining the excellent rigidity, impact resistance, heat resistance and moldability of conventional propylene-ethylene block copolymers. Copolymer and propylene polymer compositions can be provided.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Morioka 1-3-1 Nishitsurugaoka, Oi-cho, Iruma-gun, Saitama Tonen Research Institute

Claims (2)

[Claims] 1. A crystalline propylene polymer portion (A) 95.
Propylene containing 0 to 70.0 parts by weight and (B) 5.0 to 30.0 parts by weight of ethylene-propylene copolymer part
An ethylene block copolymer, wherein (i) the ethylene content is 3 to 22% by weight, (ii) the melt flow rate is 0.3 to 100 g / 10 min, and (iii) the cold xylene soluble content. Is 2.5 to 20.0% by weight, and (iv) the ethylene content of the portion soluble in cold xylene and insoluble in acetone is 4
0 to 80% by weight, (v) the ratio of the intrinsic viscosity [η] CXIS of the part insoluble in cold xylene to the intrinsic viscosity [η] CXS of the part soluble in cold xylene, [η] CXIS / [ η] CXS is 0.
4 to 2.0, and (vi) a propylene-ethylene block copolymer having a minute melting peak at 118 ° C to 130 ° C. 2. A crystalline propylene polymer (A ') 95.0 to
A composition comprising 70.0 parts by weight and 5.0 to 30.0 parts by weight of (B ') ethylene-propylene copolymer, wherein (i)
The ethylene content is 3 to 22% by weight, (ii) the melt flow rate is 0.3 to 100 g / 10 minutes, and (iii) the cold xylene soluble content is 2.5 to 20.0% by weight. , (I
v) The ethylene content of the portion soluble in cold xylene and insoluble in acetone is 40 to 80% by weight, and (v) the intrinsic viscosity [η] CXIS of the portion insoluble in cold xylene and soluble in cold xylene. Ratio of intrinsic viscosity [η] CXS, [η] CXIS /
[Η] CXS is 0.4 to 2.0, and (vi) 118 ° C.
A crystalline propylene polymer composition having a minute melting peak at 130 ° C.