JPH1036589A - Polypropylene resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polypropylene resin composition from which chlorine and alkali metal components are not extracted even by extracting the formed material by water, and capable of being suitably used for a package of an electronic part or an electronic material extremely prohibited from a halogen compound or an alkali metal compound such as a silicon wafer. SOLUTION: This polypropylene resin composition is obtained by adding 10-10000ppm an alkaline earth metal salt of a higher aliphatic carboxylic acid to a polypropylene resin containing <=5ppm chlorine content and consisting of a propylene homopolymer having >=0.930 mesopentad ratio or a block copolymer of propylene having a homopolymer part of propylene having >=0.930 mesopentad ratio with ethylene.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a specific polypropylene resin composition, and more particularly, to a specific polypropylene resin composition suitable for packaging of electronic parts, electronic materials and the like.

[0002]

2. Description of the Related Art Polypropylene is an inexpensive polymer that is lightweight and has excellent rigidity, and is used for various purposes. Particularly, because of its good solvent resistance, it is used as a package for various electronic parts or electronic materials. In such applications, the content of such components in the polymer is required to be extremely small because the eluted chlorine and alkali metals have an adverse effect on electronic components and electronic materials.

[0003] In order to remove catalyst residues which cause contamination of chlorine or alkali metals, a polymer obtained by polymerization is usually washed with alcohol or water, or alkylene glycol or its polymer is dissolved in a hydrocarbon solvent. And an ash content after the calcination of the polymer of 20 ppm or less or 10 ppm or less is provided on an industrial scale.

[0004]

Even when a molded product is produced using a catalyst having an extremely small residual catalyst as described above, when the molded product is extracted with water, chlorine and alkali metal components are extracted. It is often not suitable for electronic components or electronic material packages that extremely dislike halogen compounds and alkali metal compounds such as silicon wafers. It is desired to develop.

[0005]

Means for Solving the Problems The present inventors diligently studied compositions which solved the above problems and completed the present invention.
That is, the present invention relates to a propylene homopolymer having a mesopentad fraction of 0.930 or more, or a block copolymer of propylene and ethylene having a mesopentad fraction of 0.930 or more in a homopolymerized propylene section having a chlorine content of 5 p.
pm or less, and a salt of a higher aliphatic carboxylic acid of an alkaline earth metal with 10 to 10,000 pp.
m is a polypropylene resin composition.

A propylene homopolymer having a mesopentad ratio of 0.930 or more used in the present invention or a mesopentad ratio of 0.93 or more in a propylene homopolymerized portion.
The block copolymer of propylene and ethylene having a value of 0 or more can be produced by various production methods. For example, the block copolymer is modified with an electron-donating compound such as titanium trichloride or an electron-donating compound. It can be produced using titanium tetrachloride supported on magnesium chloride as a transition metal catalyst component and a catalyst system comprising trialkylaluminum or dialkylaluminum chloride and, if necessary, an electron-donating compound.

[0007] As a block copolymer of propylene and ethylene in which the proportion of mesopentad in the homopolymerized portion of propylene is 0.930 or more, propylene alone is polymerized using the above catalyst, and then ethylene and propylene are copolymerized. Is obtained. The ethylene content of the block copolymer is 0 to 30% by weight, and the polymerization ratio of ethylene and propylene in the copolymerized portion is 10/90 to 0/0.
100.

The molecular weight of a propylene homopolymer having a mesopentad ratio of 0.930 or more or a block copolymer of propylene and ethylene having a mesopentad ratio of 0.930 or more in a homopolymerized propylene portion has a limiting viscosity of 0. It is preferably from 0.5 to 3.0 dl / g,
Outside this range, there is a problem that the moldability is poor or the physical properties are not sufficient.

Many of the salts of higher fatty acids of alkaline earth metals contain alkali metals and chlorine as impurities, but from the viewpoint of the present application, those having 1000 ppm or less as chlorine and 1000 ppm or less as alkali metals can be preferably used. . It is better that these impurities are as small as possible, and it is particularly preferable to use those having a concentration of 500 ppm or less.

In the present invention, examples of the alkaline earth metal higher aliphatic carboxylate include calcium, zinc and magnesium as alkaline earth metals, and various compounds having 14 to 18 carbon atoms as the higher aliphatic carboxylic acid. And a calcium salt of an aliphatic carboxylic acid having 18 carbon atoms is particularly preferable.

[0011] The polypropylene resin composition of the present invention (hereinafter referred to as the composition) includes polypropylene having a low chlorine content obtained by the above-described method and 10 to 10,000 pp.
The composition can be obtained by adding a salt of a higher aliphatic carboxylic acid of an alkaline earth metal of m.

Here, it is possible to add various known additives other than the salt of a higher aliphatic carboxylic acid of an alkaline earth metal, but naturally, those containing free chlorine cannot be used. The amount of the salt of the higher aliphatic carboxylic acid of the alkaline earth metal is 10 to 10 with respect to the total composition.
000 ppm by weight, preferably 50 to 2000 ppm.

The chlorine content in the polymer is originally 5 ppm or less,
It is considered that it is not necessary to add such a large amount of a salt of a higher aliphatic carboxylic acid of an alkaline earth metal since such a preferable condition is 2 ppm or less, but it contains only an amount of chlorine which cannot be detected by ordinary analysis. Even if polypropylene is used, when extraction is performed with water without adding a predetermined amount of a salt of an alkaline earth metal higher aliphatic carboxylic acid, chlorine is detected in the extracted water.

When a strong alkali such as magnesium hydroxide or hydrotalcite is used alone as a neutralizing agent instead of a salt of a higher aliphatic carboxylic acid of an alkaline earth metal, the appearance of a molded article becomes poor. In addition, the reason is unknown, but chlorine is detected in the extraction water, which is not preferable.

In the present invention, as a method for quantifying chlorine in a resin, sodium stearate is added to a sample,
A method in which chlorine is volatilized without being burned and collected as NaCl after incineration is extracted with water and quantified by a colorimetric method using mercuric thiocyanate (colorimetric method). (Coulometric method) by titrating the generated chloride ions with electrically generated silver ions (coulometric method), and burning the sample in the same manner. A method of quantifying by ion chromatography (ion chromatography), or a method of irradiating a plate or tablet-shaped sample with X-rays and quantifying by the intensity of the obtained fluorescent X-ray (fluorescent X-ray method), sample Irradiating the neutrons with thermal neutrons to quantify the radioactivity of radioactive nuclides produced by nuclear reaction (activation analysis). As a method for quantifying chloride ions eluted from the resin, there is a method in which a sample is immersed in ultrapure water for a certain period of time, and then the extract is quantified by ion chromatography.

It is important in the present invention that the above-mentioned polypropylene resin contains chlorine of 5 ppm or less, preferably 2 ppm or less. As described above, polypropylene having a low chlorine content is obtained by thoroughly removing catalyst residues by performing various operations after polymerization. Contact treatment with alkylene oxide, particularly preferably contact treatment with alkylene oxide and water, makes it possible to make the chlorine component volatile and remove it.

[0017]

EXAMPLES Examples will be shown below for further explanation. In addition,
In Examples and Comparative Examples: Melt flow index was measured according to ASTM D1238.
(230 ° C) ・ Flexural modulus is ASTM D790 (23 ° C) ・ Izod (with notch) Impact strength is ASTM D2
56 (23 ° C.) The tensile yield strength is based on ASTM D638 (23 ° C.), and the melt flow index is 2.16 kg.
The weight was measured. The intrinsic viscosity is a 135 ° C. tetralin solution.
¹³ C-NM measured with 2,4-trichlorobenzene solution
It is calculated as the ratio of the intensity of the peak attributed to mesopentad to the intensity of all peaks attributed to the methyl group observed in the R spectrum (Zambeli et al.,
Macromolecules vol. 8,687
(1975).

Example 1 [Preparation of catalyst] 300 g of anhydrous magnesium chloride, 1.6 liter of kerosene, 2-ethylhexyl alcohol 1.
Five liters were heated at 140 ° C. for 3 hours to obtain a homogeneous solution. To this solution was added 70 grams of phthalic anhydride and 13
After stirring at 0 ° C. for 1 hour to dissolve, the mixture was filtered using a sintered filter to remove trace impurities. The filtrate was cooled to room temperature. Further, the above filtrate was slowly dropped into 8.5 liters of titanium tetrachloride cooled to -20 ° C. After completion of the dropwise addition, the temperature was raised to 110 ° C., and diisobutyl phthalate 2 was added.
15 ml was added, and the mixture was further stirred for 2 hours. The solid was separated by hot filtration, and the obtained solid was washed with n-heptane until titanium was substantially no longer detected in the washing solution. The obtained solid catalyst component contained 2.2 wt. %, Diisobutyl phthalate 11.0 wt. %.

[Polymerization and Pelletization] An autoclave having an inner volume of 700 liters, which was sufficiently dried and replaced with nitrogen, was prepared. 150 mg of a solid catalyst component (transition metal catalyst) was added, 20 kg of propylene and 17 Nl of hydrogen were added, and 70
Polymerization was performed at 2 ° C. for 2 hours. After polymerization, unreacted propylene was separated by decantation, and the polymerization product was washed three times with liquefied propylene.

Next, 0.2 g of water and 10 ml of propylene oxide were added to the product, and a further 90
Treated at 15 ° C. for 15 minutes and dried under reduced pressure for 5 minutes. This treatment with propylene oxide was repeated three times, and the produced polymer was taken out and weighed to obtain 14.50 kg of polypropylene. The amount obtained per titanium in this polymerization was 4.39 million g-PP / g-Ti.

Further, 1,2 at 120 ° C. of polypropylene
The proportion of mesopentad calculated from the ¹³ C-NMR spectrum measured with a 4-trichlorobenzene solution was 0.9.
60, 135 ° C by gel permeation chromatography
Of the weight average molecular weight and the number average molecular weight measured using 1,2,4-trichlorobenzene as a solvent (hereinafter referred to as Mw / M
n) was 5.2.

With respect to 100 parts by weight of the obtained polypropylene, 0.05 parts by weight of calcium stearate (NOF Corporation, chlorine content: 156 ppm), Irganox 1
010 (trade name, Ciba Geigy) 0.07 parts by weight and hydrotalcite 0.05 parts by weight were mixed with a Henschel mixer and pelletized at 250 ° C.

2.16K of this polypropylene pellet
g load, melt flow index at 230 ° C (hereinafter, referred to as
It is written as MFI. ) Was 5.2. When the amount of chlorine in the pellet was measured, it was 1 ppm or less, and the amount of chlorine extracted from the pellet with water was 3 ppb. Then thickness 2
mm injection sheet was molded and the physical properties were evaluated. Table 1 shows the results.

Comparative Example 1 A polymerization product obtained using the same catalyst as in Example 1 was pelletized in the same manner as in Example 1 except that the propylene oxide treatment was not performed. The MFI of the polypropylene pellet was 5.1. When the amount of chlorine in the pellet was measured, it was 19 ppm, and the amount of water-extracted chlorine from the pellet was 57 ppb. Table 1 shows the results.

Comparative Example 2 Pelletization was performed in the same manner as in Example 1 except that calcium stearate was not added during pelletization. The MFI of the polypropylene pellet was 5.1. The amount of chlorine in the pellets was 1 ppm, and the amount of chlorine extracted from the pellets with water was 10 ppb. Table 1 shows the results.

Comparative Example 3 Pelletization was carried out in the same manner as in Example 1 except that calcium stearate having a chlorine content of 2750 ppm was used. M of this polypropylene pellet
FI was 5.0. Chlorine content in pellets is 2ppm
And the amount of water-extracted chlorine from the pellets is 18 ppb
Met. Table 1 shows the results.

[0027]

[Table 1]

[0028]

Industrial Applicability The composition of the present invention has very little chlorine elution and is useful for electronic parts and electronic material packages, and is extremely valuable industrially.

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Tadashi Asanuma 1-6-6 Takasago, Takaishi-shi, Osaka Mitsui Toatsu Chemicals Co., Ltd.

Claims (3)

[Claims] 1. A propylene homopolymer having a mesopentad fraction of 0.930 or more or a block copolymer of propylene and ethylene having a mesopentad fraction of 0.930 or more in a homopolymerized propylene section having a chlorine content of 5 pp.
m or less, a salt of a higher aliphatic carboxylic acid of an alkaline earth metal in a polypropylene resin of 10 to 10,000 ppm.
A polypropylene resin composition added. 2. The polypropylene resin composition according to claim 1, wherein the polypropylene resin is obtained by contacting with an alkylene oxide after polymerization. 3. The polypropylene resin composition according to claim 1, wherein the salt of a higher aliphatic carboxylic acid of an alkaline earth metal has a chlorine content of 1000 ppm or less and an alkali metal content of 1000 ppm or less.