JPH07117171A - Deterioration resistant polypropylene form - Google Patents

Abstract

PURPOSE:To obtain a form, which improves resistance to deterioration, capable of being used as the composite form of various metals, which could not be used due to copper pollution deterioration, and is prominent in physical balance, by a method wherein polypropylene having halogen less than a specified value is employed as polypropylene which contacts a metal. CONSTITUTION:Polypropylene, containing less than 2 wt.ppm of halogen, is used as polypropylene which contacts a metal. The employed polypropylene contains not only the individual polymer of propylene but also a random copolymer or a block copolymer of other olefin of two kinds or more. Further, the composite of other kinds of polymers than polypropylene can by used as well. The employing rate of constituents except polypropylene is preferably less than 10wt% in random copolymer but the polymerization of propylene individual is preferably more than 50wt% in the case of block copolymer. On the other hand, less than 30wt% is preferable when the composite of other kind polymer is made.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polypropylene molded article having excellent deterioration resistance.

[0002]

2. Description of the Related Art Polypropylene is easy to process, has excellent electrical, mechanical, and chemical properties, is flexible, has heat resistance, is hydrophobic, and is inexpensive to obtain. Since it has the feature that it can be used, it is very often used as a molding material in many products. However, it is known that when polypropylene is in contact with a metal such as copper, iron, manganese, or cobalt, it suffers from so-called copper damage and is rapidly aged or oxidatively deteriorated to lower its mechanical strength.

Since polypropylene has tertiary carbon in its structure, it is basically easily decomposed by radicals and is oxidized and deteriorated by light, heat, radiation, oxygen and the like. In particular, contact with a metal such as copper, manganese, iron, or cobalt accelerates the deterioration significantly, and the deterioration is further accelerated by heating.

Although the mechanism of copper damage is not exactly known, when a metal such as copper contacts polypropylene, these metal ions diffuse into polypropylene and act as a catalyst for radical decomposition reaction of polypropylene. Is believed to be. Decomposes triazoles, tetrazoles, substituted hydrazines, malonic acid amides, oxalic acid amides or phenolic antioxidants and peroxides that suppress radical reactions that form stable compounds with copper to prevent copper damage A copper damage inhibitor such as a sulfur-based antioxidant is added.

[0005]

However, some of these copper damage inhibitors adversely affect the physical properties by addition, and depending on the type of the inorganic filler added to improve the mechanical properties, the deterioration resistance effect may be deteriorated. In some cases, it may not be seen enough. That is, it cannot be said that the currently used polypropylene has a sufficient copper-damage-preventing effect, and if polypropylene having excellent copper-damage resistance can be used, the stability of the metal-polypropylene composite molded product can be increased. Thus, the characteristics of polypropylene can be used in a wider range of products, which is extremely useful in industry.

[0006]

[Means for Solving the Problems] The inventors of the present invention have conducted diligent research to solve the above-mentioned problems, and have noticed that calcium carbonate, which is usually added to polypropylene, also has a slight copper damage preventing effect. As a result of various studies on the effect of the catalyst residue contained in polypropylene, specific components in the catalyst residue contained in polypropylene have a great influence on the deterioration due to copper damage, and if that component is removed, the deterioration resistance is good. The present invention has been completed by finding out that it has various characteristics.

That is, the present invention is a metal-polypropylene composite molded article, characterized in that polypropylene having a halogen content of 2 ppm by weight or less is used as the polypropylene in contact with the metal.

The polypropylene used in the present invention includes not only a homopolymer of propylene but also a random copolymer or a block copolymer with two or more kinds of other olefins, and a polymer other than polypropylene. Can also be used in combination. For example, polypropylene, polybutene, polypentene, polyhexene, polyheptene, polyoctene and other poly-α-olefins, polycyclopentene, a complex with a cyclic polyolefin such as polynorbornene, and a copolymer of propylene and an olefin having 2 to 20 carbon atoms. The proportion of components other than propylene used is preferably less than 10 wt% in random copolymerization and 50 wt% or more of propylene alone in polymerization in block copolymerization. When another type of polymer is compounded, its proportion is preferably 30 wt% or less.

As the catalyst used for producing the polypropylene used in the present invention, a catalyst generally used for industrially producing polypropylene is used. For example, a titanium trichloride catalyst or a carrier catalyst in which titanium trichloride or titanium tetrachloride is supported on a carrier such as magnesium chloride is used. Further, a homogeneous catalyst represented by a combination of dicyclopentadienyl zirconium dichloride and aluminoxane can be used.

As a polymerization method, a conventional polymerization method such as a solvent polymerization method, a bulk polymerization method or a gas phase polymerization method is used. When the activity of the catalyst is not sufficiently high, the produced polymer is washed to remove a catalyst residue. Can be reduced. Since the above catalyst contains a large amount of halogen such as chlorine, if the halogen content is high even after washing, an amine compound,
Dehalogenation treatment is preferably performed with an oxirane compound, ammonia, an organic fatty acid, or the like.

As described above, in the present invention, it is essential to use polypropylene having a halogen content of 2 ppm by weight or less, and a halogen content of 2 ppm by weight.
When it exceeds m, the deterioration resistance is lowered, and when the halogen content is 2 ppm by weight or less, the deterioration resistance is greatly improved.

As a method for quantifying halogen, a known method can be used. For example, as a method for quantifying chlorine, add sodium stearate to the sample and volatilize it without burning, extract the chlorine collected as NaCl after ashing with water, and quantify it by a colorimetric method with mercuric thiocyanate. Method (colorimetric method), a method of burning a sample in a mixed gas stream of argon gas and oxygen gas, and titrating the generated chlorine ion with silver ion generated coulometrically (coulometric method), Similarly, after burning the sample, a method of quantifying the generated chlorine ions by an ion chromatograph (ion chromatograph method), or irradiating the plate- or tablet-shaped sample with X-rays to obtain a fluorescent X-ray Method by fluorescent intensity (fluorescent X-ray method), method of irradiating sample with thermal neutron and quantifying radioactivity of radionuclides of chlorine produced by nuclear reaction (activation analysis method) Etc., and the like.

The present invention is a metal-polypropylene composite molded product using the above-mentioned polypropylene, which is a metal filler-polypropylene composite in which a wire or tube of a metal such as copper or iron is coated with polypropylene or a metal filler is added. Is a molded product obtained by molding.

The metal-polypropylene composite molded article of the present invention is characterized by having high deterioration resistance, and the deterioration resistance was measured as follows. The test method is as follows: a polypropylene sheet is closely adhered to a copper plate and wrapped, and a constant temperature air bath method is used.
It was placed in an oven in which hot air of 0 ° C. circulates, and the time until deterioration (crush embrittlement) was observed was measured. The deterioration point was confirmed by a method of observing the occurrence of powdery deterioration. Thirteen
The life time at a normal temperature was estimated from the Arrhenius plot from the life time at 0 ° C.

When the molded article of the present invention is molded, the polypropylene used in the present invention may be added with various stabilizers used in ordinary polypropylene. It is also possible to add various inorganic fine particles and organic fine particles, for example, silica, alumina, kaolin, talc, zeolite, titanium oxide, calcium carbonate, calcium silicate, stearic acid ester, and other additives usually used for polypropylene. .

[0016]

EXAMPLES The present invention will be further described with reference to the following examples.

Example 1 A vibration mill equipped with four grinding pots having an inner volume of 4 liters and containing 9 kg of steel balls having a diameter of 12 mm was prepared. Magnesium chloride (300 g), diisobutyl phthalate (75 ml) and titanium tetrachloride (60 ml) were added to each pot in a nitrogen atmosphere and pulverized for 40 hours.

10 g of the above co-ground product was placed in a 200 ml flask, 60 ml of toluene was added, the mixture was stirred at 114 ° C. for 30 minutes, and then allowed to stand to remove the supernatant. Then n-heptane 100 ml
The solid content was washed 3 times at 20 ° C. and dispersed in 100 ml of n-heptane to obtain a solid catalyst component slurry. The obtained solid catalyst component contained 1.9 wt% titanium and 14.2 wt% diisobutyl phthalate.

A fully dried and nitrogen-substituted autoclave having an internal volume of 5 liters was prepared, and 0.2 ml of triethylaluminum diluted with 100 ml of heptane, 0.1 ml of cyclohexylmethyldimethoxysilane and 15 mg of the above transition metal catalyst were added, and 1.5 kg of propylene and hydrogen were added. 1.7 Nl was added and the mixture was polymerized at 70 ° C for 2 hours. After the polymerization, unreacted propylene was purged, 0.02 g of water and 1 ml of propylene oxide were added, and the mixture was further treated at 90 ° C. for 15 minutes. The resulting polymer was taken out and weighed by repeating the drying treatment for 5 minutes under reduced pressure three times to obtain 675 g of polypropylene.

The intrinsic viscosity (hereinafter abbreviated as η) measured with a 135 ° C. tetralin solution of polypropylene is 1.6.
5. The boiling n-heptane extraction residual rate (weight of extraction residual polymer / weight of pre-extraction polymer expressed as 100 fraction, hereinafter abbreviated as II) measured by Soxhlet extractor is 98.1.
%, Gel permeation chromatograph at 135 ℃ 1,
The ratio of the weight average molecular weight to the number average molecular weight (hereinafter abbreviated as MW / MN) measured with 2,4-trichlorobenzene as a solvent was 5.5.

To measure the ash content of this polypropylene, 20 g of a sample was put into a magnetic crucible and slowly ashed so as not to burn rapidly. Further, it was put into an electric furnace at 850 ° C. and heated for 30 minutes to completely incinerate. When cooled in a desiccator and measured for ash, it was 23 ppm by weight. Further, the amount of chlorine was measured by activation analysis and found to be 0.54 ppm by weight.

With respect to 100 parts by weight of this polypropylene powder, 0.1 part by weight of 2,6-di-t-butyl-p-cresol,
0.01 parts by weight of calcium stearate and 0.2 parts by weight of Irganox-1330 (trade name, Ciba Geigy) were added and mixed, and then extruded at 250 ° C. to form pellets. The pellets were then injection molded at 270 ° C to a thickness of 2 mm, length,
A sheet having a width of 50 mm was obtained. The surface of this sheet was degreased with acetone, and then a 0.5 mm-thick copper foil was closely adhered to the surface of the sheet and wrapped to form a sample. 130 this sample
It was placed in an oven in an air atmosphere in which hot air of ℃ circulates, and the time until the occurrence of powdery deterioration was observed on the sheet was measured.

Example 2 Instead of 0.1 ml of cyclohexylmethyldimethoxysilane in Example 1, 0.1 ml of dipropyldimethoxysilane was used.
1250 g of polypropylene was obtained in the same manner as in Example 1 except that 1.7 Nl of hydrogen was added and the polymerization temperature was changed to 75 ° C.
Η of this polypropylene is 1.70, II is 98.2%, MW /
The MN was 5.1. The ash content of this polypropylene was 13 ppm by weight, and the chlorine content was 0.48 ppm by weight. It took 580 hours until the occurrence of powdery deterioration of the sheet produced in the same manner as in Example 1 using this polypropylene powder.

COMPARATIVE EXAMPLE 1 620 g of polypropylene was obtained in the same manner as in Example 1 except that water and propylene oxide were not added after the polymerization of polypropylene in Example 1. Η of this polypropylene is 1.65, II is 98.0%, M
The W / MN was 5.3. The ash content of this polypropylene was measured to be 26 ppm by weight, and the chlorine content was measured to be 12.8 ppm by weight. It was 100 hours until the occurrence of powdery deterioration of the sheet produced in the same manner as in Example 1 using this polypropylene powder.

Example 3 Isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dichloride obtained by lithiation of isopropylcyclopentadienyl-1-fluorene synthesized according to a conventional method and reaction with zirconium tetrachloride was methylated. 0.2 g of isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dimethyl obtained by methylation with lithium was dissolved in 100 ml of toluene, and 4.3 g of triethylaluminum was added as a catalyst component. Then, the above catalyst component was inserted into an autoclave having a volume of 200 liters charged with 100 liters of toluene.

After adding propylene to a 3 kg / cm ² gauge and raising the temperature to 20 ° C., 1.28 g of triphenylmethanetetra (pentafluorophenyl) boron is added to 100 parts of toluene.
The solution dissolved in ml was added to the autoclave to initiate polymerization, and polymerization was carried out at 20 ° C. for 2 hours while maintaining 3 kg / cm ² gauge.

After completion of the polymerization, the content was filtered and dried to obtain 6.9 kg of a polymer. According to ¹³ C-NMR, the syndiotactic pentad fraction is 0.88, η is 1.13, MW
/ MN was 2.2. The amount of chlorine in this polypropylene was measured to be 0.8 ppm by weight, and the time until the occurrence of powdery deterioration of the sheet produced by using this polypropylene powder in the same manner as in Example 1 was observed.
It was time.

[0028]

Industrial Applicability The metal-polypropylene composite molded product of the present invention has good deterioration resistance and can be used as a composite molded product with various metals which could not be used due to severe deterioration due to copper damage, and has excellent physical property balance. A molded product is obtained, which is extremely valuable industrially.

Claims (1)

[Claims] 1. A metal-polypropylene composite molded article, wherein polypropylene having a halogen content of 2 ppm by weight or less is used as the polypropylene which comes into contact with a metal.