JPS58173145A - Production of modified propylene/ethylene block copolymer composition - Google Patents

Abstract

PURPOSE:To produce the titled compsn. having excellent gloss value, transparency and resistace to whitening by shock, by heating a mixture consisting of a propylene/ethylene block copolymer, low-density PE and high-density PE in the presence of an org. peroxide. CONSTITUTION:0.001-1.0wt% org. peroxide such as methyl ethyl ketone peroxide is added to a mixture consisting of a propylene/ethylene block copolymer, 1-15wt% low-density PE having an MI (190 deg.C) of 0.5g/10min or above and a density of 0.930 or below, and 1-30wt% high-density PE having an MI (190 deg.C) of 3-30g/10min and a density of 0.94 or above. The mixture is heat-treated at 180-300 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a fabric that retains the excellent impact resistance and other mechanical properties that brobylene-ethylene block copolymer originally possesses, and also maintains high gloss.

The present invention relates to a method for producing a modified globylene-ethylene block copolymer composition with improved optical properties such as transparency and impact whitening resistance.

Propylene-ethylene floc copolymer (hereinafter referred to as P/E)
(sometimes abbreviated as "Block Koborif") has excellent mechanical properties, especially impact resistance, and also has some excellent optical properties such as gloss and transparency, so it is used as a molding material for various molded products. The fields of use are expanding. However, molded products made of P/E block copolymers undergo m* whitening phenomenon, where the surface becomes cloudy due to impact, which significantly reduces the commercial value of the product, especially in products where the appearance of the molded product is important.

Conventionally, a P/g block copolymer composition in which a P/g block copolymer is mixed with high-density polyethylene has been proposed as a means to improve the impact whitening resistance of P/F block copolymers. However, the molded products of the above compositions do not have sufficient impact whitening resistance. In addition, in order to improve impact whitening resistance, it is necessary to increase the mixing ratio of high-density polyethylene, and as a result, the mechanical properties and optical properties originally possessed by the P/E block copolymer deteriorate. This creates the problem of

The present inventors have already developed a method for improving the impact whitening properties of P/E block copolymers by avoiding the above-mentioned problems.
We proposed a method of decomposing a mixture of E-block copolymer and high-density polyethylene using an organic peroxide. Subsequently, as a result of further studies on the above method, it was found that after mixing low density polyethylene as a third component with the P/E block copolymer and high density polyethylene, the modified material obtained by the above method was decomposed with an organic peroxide. P/E
The present inventors have discovered that the transparency of block copolymer compositions can be significantly improved without impairing other properties such as impact whitening resistance, and have completed the present invention.

That is, the present invention provides a modified floylene-ethylene block copolymer composition characterized in that a mixture of a propylene-ethylene block copolymer, low density polyethylene and ~high density polyethylene is heat treated in the presence of an organic peroxide. #! It is a construction method.

In the present invention, the heat treatment performed in the presence of an organic peroxide is a P/g block copolymer.

It is very important to do so on mixtures of low density polyethylene and high density polyethylene. That is, even if P/E block copolymer, low-density polyethylene, and high-density polyethylene are heat-treated in the presence of an organic peroxide and then mixed together, the impact whitening resistance is not sufficiently improved, and the present invention Most of the objectives for the period cannot be achieved. P
/ E Block Copoly 7-1 The method of mixing low-resolution polyethylene and high-density polyethylene is not particularly limited. For example, a method of mechanically mixing both in the form of granules or powder, or a method of polymerizing the P/E block copolymer described later and then polymerizing high density polyethylene. After mixing by polymerization, low density polyethylene is mixed. A method of mechanically mixing is preferred. In the above-mentioned mixing by polymerization, a new catalyst can be supplied as necessary during the polymerization of high-density polyethylene y. Also, ethylene monomer is 1
According to the present invention, organic peroxides may contain different types of additives such as propylene, butene-1, etc. in the range of 0 weight or less. As long as it is present when heat treating the mixture, there are no particular restrictions on the time of mixing. Generally, Ii! is premixed with a P/E block copolymer, low density polyethylene or high density polyethylene. A mode in which the fence, P/g block copolymer, low density polyethylene and high density polyethylene are mixed together at the time of mixing, and a mode in which the P/B block copolymer, low density polyethylene and high density polyethylene are mixed after all are mixed, etc. An appropriate aspect can be selected. As for the mixing method of the organic peroxide, any known mixing method may be used without any particular restrictions.

For example, by dissolving organic peroxide in a suitable solvent, P/E
It is also possible to achieve more uniform mixing by applying to block copolymers, low density polyethylene and/or high density polyethylene and drying the solvent. p/
The heat treatment temperature for the mixture of the E block copolymer, low density polyethylene and high density polyethylene is set to a temperature above 1 degree for the melting of the mixture and above a temperature plate for the decomposition of organic peroxide. However, if the heat treatment temperature is too high, P
Fi1 is generally used because it causes thermal deterioration of the polymer, low density polyethylene or high density polyethylene.
It is preferable to perform the heat treatment at a temperature of 80°C to 30°C.

In the present invention, any P/E block 5 polymer obtained by a known production method can be used without particular limitation. To give an example of a typical production method, first, only propylene monomer is completely homopolymerized, then unreacted propylene monomer is removed, and then ethylene monomer or a mixed monomer of ethylene monomer and propylene monomer is charged and polymerization is carried out. can be mentioned. Moreover, low density polyethylene is 0.950 or less, preferably 0.930 to 0.925
There are no particular limitations as long as it is a homopolymer of ethylene or a random copolymer of ethylene and a different monomer such as propylene or butene-1 having a density of . In particular, the melt flow index (MFI) was 0.5F/10 minutes (at 19
0℃) or higher, preferably 5F/10 minutes (at 190℃)
The above are preferred. Furthermore, high density polyethylene is a homopolymer of ethylene or ethylene and propylene having a density of 0.94 or higher.

There is no particular restriction as long as it is a fundum copolymer with a different type of monomer such as butene-1. Especially, MFI is 3~30f/1
0 minute (at 190°C) high density polyethylene is preferred. According to the present invention, in the mixture of p/z block copolymer, low density polyethylene and high density polyethylene, the content ratio of low density polyethylene is 1 to 15 weight x 1, preferably 3 to 15 weight x, and the content ratio of high density polyethylene is 1 to 15 weight x 1. is preferably 1 to 30 weight X, preferably 5 to 25 weight X.

In this case, it is preferable to adjust the total weight of the mixture to 2 to 65 weight X.

Furthermore, known organic peroxides are generally used in the present invention. Typical organic peroxides include, for example, ketone peroxides such as methyl ethyl ketone peroxide and methyl imbutyl ketone peroxide; diasilver oxides such as imbutyryl peroxide and acetyl peroxide; and diisopropylbenzene hydroperoxide.

Other hydroperoxides: 2,5-dimethyl 2
,5-di(1-butylperoxy)hexane, 1.3
-Dialkyl peroxides such as -bis-(t-butylperoxyinglobil)benzene: 1,1-di-t-butylperoxy-cyclohexane, other peroxyketals; t-butyl peroxyacetate, t-butyl peroxy Alkyl peresters such as oxybenzoate:
Examples include t-butyl baroxyingropyl carbonate and other bar carbonates. The amount of organic peroxide used is P/E block copolymer.

0.001 to 1.0 weight x1 preferably 0.01 to a mixture of low density polyethylene and high density polyethylene
~0.5 weight X is typical.

As is clear from the Examples and Comparative Examples described above, the modified P/E block copolymer composition obtained by the method of the present invention has the mechanical properties originally possessed by the P/B block copolymer without causing any practical problems. It has better optical properties, especially transparency, than the P/E block copolymer while maintaining the same characteristics, and also has excellent impact whitening resistance. Therefore, it can be suitably used as a material for various containers such as automobile batteries whose interiors need to be seen through, and the fields of use of p/E block copolymers can be further expanded.

Ceramics 1 The modified polypropylene-ethylene block copolymer composition obtained by the method of the present invention may contain known additives such as antioxidants, heat stabilizers, ultraviolet absorbers, and the like.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples.

In the ceramics, Examples and Comparative Examples, the melt flow index (MF4), Izot impact strength, impact whitening degree, glossiness and haze were measured by the following methods.

6MFI: Measured according to A8'f'MD D1238.

o Fissibut impact strength: Nikko Ankelberg V22A-
65.6 x 12.7 x 0 by 120 type injection molding machine
．． A test piece of No. 31 was prepared and measured according to ASTM D-256.

O impact whitening dust: 90 x 60 x by the above injection molding machine
A test piece of 2- was prepared. This test piece was fixed on a steel plate cut out to a size of 60 mm, and 5 mm was placed in the center of the cut out part.
After dropping a 5f steel ball from a height of 2m, the test piece was
The sample was left at 3°C for 48 hours, and the diameter of the whitened area at the point where the steel ball fell was measured. In addition, the degree of whitening is classified as 1st class if there is no whitening at all.

The evaluation was divided into 5 grades, with those that were completely whitened being grade 5.

O Glossiness: 60×40 is by the injection molding machine
A test piece of x 3 mm was prepared and tested according to ASTM D-523.
Measured according to.

O haze: 90 x 60 x 1- by the injection molding machine
A test piece was prepared and measured according to ASTM D-1006. Further, the ethylene content in the P/4 block copolymer was determined by infrared absorption spectrum.

Example 1 Contains 4.9 weight X of ethylene moieties, MFll, 6f/
Powdered P/E block copolymer for 10 minutes (1 & 230°C) to a density of 0.955. MFI2 Of/10 minutes (at 1
90C) pellet-shaped high*1 polyethylene, density 0.9
18. MFI45 F/10 minutes (at 190°C) pellet-shaped low density polyethylene was added in such a manner that the respective proportions in the mixture were as shown in Table 1, and to this was added 2,5-dimethyl-2,5-( t-butylperoxy)-hexane (
MBH) was added to the mixture in the proportions shown in Table 1, and further an antioxidant, a heat stabilizer, and a lubricant were added and mixed in a Henschel mixer. Next, Nakatani Machinery 11Vs
Modified p was extruded using a K40 vented 40 φ extruder while controlling the resin temperature at the die exit to 260°C.
/E block copolymer composition pellets were obtained.

The composition was measured for MFI, haze, gloss, II impact whitening and Izod impact strength. The results are also shown in Table-1.

, / /' / / Example 2 A pellet of a modified P/E block copolymer composition was obtained in the same manner as in Example 1044, except that the low density polyethylene was replaced with the pellet-shaped low density polyethylene shown in Table 2. . The same measurements as in Example 1 were performed on the carcass composition. The results are also shown in Table-2.

Example 5 A pellet of a modified P/E block copolymer composition was obtained in the same manner as in Example 1 except that the high density polyethylene in A4 was replaced with the pelletized high density polyethylene shown in Table 3. The same measurements as in Example 1 were performed on this composition. The results are also shown in Table 3.

Example 4 In 14 of Example 1, the type of organic peroxide was changed to MBH.
A modified p/E block copolymer was prepared in the same manner except that 1,6-bis-(t-butylperoxy-isoglobil)benzene (BPB) and di-t-butylperoxide (TBP) were used instead of A beret of the composition was obtained. The same measurements as in Example 1 were performed on this composition. The results are shown in Table 4.

Example 5 Propylene was polymerized at 60° C. for 3 hours using a catalyst consisting of titanium trichloride and diethylaluminum monochloride. Next, unreacted propylene and ethylene topropylene were supplied so that the gas phase molar concentration ratio was 174, and hydrogen gas was further added to achieve a predetermined MI. The polymerization temperature of this polymer was 50°C.

The mixed gas was continued to be supplied until the ethylene content in the polymer reached 5X by weight. The concentration of each gas was controlled by process gas chromatography. After reaching a predetermined ethylene content, unreacted gas was purged after death, and then ethylene gas was supplied to continue polymerization to produce high-density polyethylene. Hydrogen gas was also supplied at the same time to achieve a predetermined MFI. Ethylene gas was continued to be supplied until the total ethylene content in the polymer reached 20X by weight. Polymerization was terminated by purging unreacted gas and then adding methanol. After removing the catalyst and APP, a white powdered polymer was recovered. The ethylene content of the polymer is 21x.

The MI value was 2.2. Table 5 shows the low density polyethylene and organic peroxide MBH used in Example 1 for the polymer.
Then, using the same extruder as in Example 1 and under the same conditions, a pellet of a modified P/W block copolymer composition was obtained. Regarding the pattern composition 3, the same measurements as in Example 1 were performed. The measurement results are shown in Table-5. A comparative example of experimental AIFi is shown.

Comparative Example 1 The P/g block copolymer used in Example 1 was blended with only high-density polyethylene used in Example 1, blended with only low-density polyethylene, and containing no polyethylene at all. Oxide MBH
were mixed in the proportions shown in Table 6, an antioxidant, a heat stabilizer, and a lubricant were further added and treated in the same manner as in Example 1, and the same measurements as in Example 1 were performed. The results are also shown in Table-6. Table 6 shows the measurement results for the P/E block copolymer used in Example 1 alone. In addition, the P/E block Kobo of Example 1,
After adding MBH to reamer, high-density polyethylene, and low-density polyethylene, and pelletizing them in the same manner as in Example 1, similar measurements were also performed on a mixture of these in the proportions shown in Table 6. The results are also shown in Table-6.

Claims (1)

[Claims] t Propylene-ethylene block copolymer. A method for producing a modified propylene-ethylene block copolymer composition, which comprises heat-treating a mixture of low-density polyethylene and high-density polyethylene in the presence of an organic peroxide. 2. The method of claim 1, wherein the mixture contains 1 to 15 weights x of low density polyethylene and 1 to 60 weights x of high density polyethylene. (v) The amount of organic peroxide used is 0.001% of the mixture.
2. The method of claim 1, wherein the weight is 1 to 1 weight X.