JPH0848835A - Deterioration-resistant thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain a polypropylene-based thermoplastic resin composition, having good resistance to deterioration, useful in the form of composite molded products with various metals which have been unusable because of their severe metal deterioration, and capable of giving molded products with well-balanced physical properties. CONSTITUTION:This metal deterioration-resistant thermoplastic resin composition as a thermoplastic resin composition to be come into contact with metals, comprises a polypropylene with a halogen content of <=2wt.ppm and a thermoplastic elastomer with a halogen content of <=2wt.ppm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene-based thermoplastic resin composition having excellent deterioration resistance.

[0002]

BACKGROUND OF THE INVENTION Polypropylene-based thermoplastics are easy to process, have excellent electrical, mechanical, and chemical properties, are flexible, have heat resistance, are hydrophobic, and are inexpensive. It is used in many products because it has the characteristics that it can be obtained. However, it is known that when polypropylene itself 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.

That is, since polypropylene has tertiary carbon in its structure, it is basically prone to radical decomposition and susceptible to oxidation and deterioration by light, heat, radiation, oxygen and the like. In particular, it is known that deterioration is remarkably promoted by contact with a metal such as copper, manganese, iron or cobalt, and this deterioration is further accelerated by heating.

Although the mechanism of metal deterioration is not known exactly, when a metal such as copper contacts polypropylene,
It is considered that those metal ions diffuse into polypropylene and act as a catalyst for the radical decomposition reaction of polypropylene. Such metal deterioration similarly occurs in a polypropylene-based thermoplastic resin composition composed of polypropylene and a thermoplastic elastomer.

Generally, triazoles, tetrazoles, substituted hydrazines, malonic acid amides, oxalic acid amides or phenolic compounds which suppress a radical reaction, which form a stable compound with a metal such as copper to prevent metal deterioration. So-called copper damage inhibitors such as antioxidants and sulfur-based antioxidants that decompose peroxides are added.

[0006]

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, the copper-damage-preventing effect of the polypropylene-based thermoplastic resin composition currently used cannot be said to be sufficient, and if a polypropylene-based thermoplastic resin excellent in copper-damage resistance can be used, a metal-polypropylene-based thermoplastic resin can be used. It is possible to improve the stability of the composite molded article, and the characteristics of the polypropylene-based thermoplastic resin can be used in a wider range of products, which is extremely useful in industry.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and calcium carbonate, which is usually added to polypropylene-based thermoplastic resins, also shows a slight copper damage-preventing effect. Focusing on this point, various effects of impurities such as catalyst residues and additives contained in the thermoplastic resin were examined, and it was found that specific components of the impurities contained in the thermoplastic resin had a great influence on the deterioration due to the metal. However, the inventors have found that if the components are removed, they have good characteristics of deterioration resistance and completed the present invention.

That is, the present invention is characterized in that a mixture of polypropylene having a halogen content of 2 ppm by weight or less and a thermoplastic elastomer having a halogen content of 2 ppm by weight or less is used as the thermoplastic resin composition in contact with a metal. It is a metal deterioration-resistant thermoplastic resin composition.

The polypropylene used in the present invention includes not only a propylene homopolymer but also a random copolymer or a block copolymer with two or more kinds of other olefins. For example, polypropylene, polybutene, polypentene, polyhexene, polyheptene, polyoctene and other poly-α-olefins and polycyclopentene, a complex with a cyclic polyolefin such as polynorbornene,
A copolymer of propylene and an olefin having 2 to 20 carbon atoms is exemplified, but the proportion of components other than propylene used is less than 10% by weight in random copolymerization and propylene alone in block copolymerization. It is preferable that the above-mentioned polymerization is 50% by weight or more of the whole.

These polypropylenes are industrially available and can be easily produced. As a catalyst used for producing polypropylene,
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 the 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 resulting 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.

The thermoplastic elastomer used in the present invention is an elastomer obtained by copolymerizing ethylene with a higher olefin such as hexene, octene, decene and undecene, and an olefin elastomer such as propylene / ethylene rubber and propylene / ethylene / diene rubber. And styrene / butadiene rubber, styrene / isoprene rubber, and hydrogenated elastomers thereof.

These thermoplastic elastomers are already commercially available and can be produced by using a homogeneous catalyst represented by a combination of dicyclopentadienyl zirconium dichloride and aluminoxane. it can.

When the content of halogen contained in these thermoplastic elastomers is high, an amine compound,
It is necessary to perform a dehalogenation treatment with an oxirane compound, ammonia, an organic fatty acid, etc., so that the content of halogen is 2 ppm by weight or less.

As described above, in the present invention, it is essential to use a mixture of polypropylene containing 2 ppm by weight or less of halogen and a thermoplastic elastomer containing 2 ppm by weight or less of halogen. The halogen content of the thermoplastic composition thus obtained is 2 ppm by weight or less. When the halogen content of the thermoplastic composition exceeds 2 ppm by weight, the deterioration resistance to metal is lowered, and when the halogen content is 2 ppm by weight or less, the deterioration resistance is greatly improved.

Here, 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 the above-mentioned polypropylene-based thermoplastic resin composition. As a metal-thermoplastic resin composite molded article using the same, a metal wire such as copper or iron, a tube or the like is used as the thermoplastic resin composition. It can be used as a molded product obtained by molding with a metal filler thermoplastic resin composite in which a metal filler is added or a metal filler is added.

A metal-thermoplastic resin composite molded article using the metal-polypropylene thermoplastic resin composition of the present invention is characterized by high deterioration resistance, and the deterioration resistance is measured as follows. did. As a test method, a copper plate was closely adhered to a thermoplastic resin composition sheet and wrapped, and the sheet was placed in an oven in which hot air of 130 ° C. circulates by an air constant temperature bath method, 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.
The lifetime at a normal temperature was estimated from the Arrhenius plot from the lifetime of 130 ° C.

When a molded product is molded using the composition of the present invention, various stabilizers used in ordinary polyolefins can be added and used. 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 polyolefins. .

[0020]

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. 300 g of magnesium chloride, 75 ml of diisobutyl phthalate, and 60 ml of titanium tetrachloride 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
-The solid content was washed with 100 ml of heptane three 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% by weight of titanium and 14.2% of diisobutyl phthalate.
% By weight.

A fully dried autoclave having an internal volume of 5 liters and having been replaced with nitrogen was prepared, and n-heptane of 100 m was prepared.
0.2 ml of triethylaluminum diluted to 1 ml, 0.1 ml of cyclohexylmethyldimethoxysilane and 15 mg of the above transition metal catalyst were added, 1.5 kg of propylene and 1.7 Nl of hydrogen were added, and polymerization was carried out at 70 ° C. for 2 hours. After the polymerization, unreacted propylene was purged, and then water was added to 0.02.
g and 1 ml of propylene oxide, and
It was treated at 0 ° C. for 15 minutes. The drying treatment for 5 minutes under reduced pressure was repeated 3 times, and the produced polymer was taken out and weighed to obtain 675 g of polypropylene.

The intrinsic viscosity (hereinafter abbreviated as η) measured with a 135 ° C. tetralin solution of polypropylene is 1.65, and the boiling n-heptane extraction residual rate (weight of extraction residual polymer / extraction) measured with a Soxhlet extractor. The weight of the previous polymer is expressed as a percentage, and is hereinafter abbreviated as II.)
Is 98.1%, and the ratio of the weight average molecular weight to the number average molecular weight (hereinafter, Mw /
It is abbreviated as Mn. ) 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 in 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 231
The amount was ppm. Further, the amount of chlorine was measured by activation analysis and found to be 0.54 ppm by weight.

As a thermoplastic elastomer, an ethylene / octene elastomer (made by Dow, ENGAGE800
1 was similarly treated with propylene oxide, and the chlorine content was 0.82 ppm).

With respect to 100 parts by weight of this polypropylene powder, 40 parts by weight of the above thermoplastic elastomer, 2,6-
Di-t-butyl-p-cresol 0.1 part by weight, calcium stearate 0.01 part by weight, and Irganox-133
0.2 parts by weight of 0 (trade name, Ciba Geigy) was added and mixed, and then extruded at 250 ° C. to form pellets. Then, the pellets were injection-molded at 270 ° C. to obtain a sheet having a thickness of 2 mm, a length and a width of 50 mm. 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. This sample was placed in an oven in an air atmosphere in which hot air of 130 ° C. circulates, and the time until the occurrence of powdery deterioration was observed on the sheet was measured. As a result, powdery deterioration occurred at 690 hours.

Example 2 Example 1 was repeated except that 0.1 ml of dipropyldimethoxysilane was used in place of 0.1 ml of cyclohexylmethyldimethoxysilane in Example 1 and 1.7 N liters of hydrogen was added to control the polymerization temperature to 75 ° C. Same as 1250
g of polypropylene was obtained. Η of this polypropylene was 1.70, II was 98.2%, and Mw / Mn was 5.1. The ash content of this polypropylene was measured 13
It was ppm by weight, and when the amount of chlorine was further measured, it was 0.48 ppm by weight. It took 870 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 9
The amount was 8.0% and Mw / Mn was 5.3. The ash content of this polypropylene was measured to be 26 ppm by weight,
Further, when the amount of chlorine was measured, it was 12.8 ppm by weight. Example 1 using this polypropylene powder
It took 200 hours until the occurrence of powdery deterioration of the sheet prepared in the same manner as in (4).

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,
4.3 g of triethylaluminum was added to make a catalyst component. Then, the volume 2 charged with 100 liters of toluene
The above catalyst component was inserted into a 00 liter autoclave.

After adding propylene to 3 kg / cm ² gauge and raising the temperature to 20 ° C., a solution prepared by dissolving 1.28 g of triphenylmethanetetra (pentafluorophenyl) boron in 100 ml of toluene was added to the autoclave for polymerization. Was started and polymerization was carried out at 20 ° C. for 2 hours while maintaining the pressure at 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 was 0.88, η was 1.13, and Mw / Mn was 2.2. The amount of chlorine in this polypropylene was measured and found to be 0.8 ppm by weight. The time period until the occurrence of powdery deterioration of the sheet produced in the same manner as in Example 1 using this polypropylene powder was observed was 610 hours. there were.

[0033]

EFFECT OF THE INVENTION The polypropylene-based thermoplastic resin composition 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 metal deterioration in the past, and was excellent in physical property balance. A molded product is obtained, which is extremely valuable industrially.

Claims (1)

[Claims] 1. A thermoplastic resin composition which is in contact with a metal, comprising polypropylene having a halogen content of 2 ppm by weight or less and a thermoplastic elastomer having a halogen content of 2 ppm by weight or less. Resin composition.