KR100808723B1 - Composition for producing high melt strength polypropylene - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin composition having excellent vacuum formability and high elasticity, specifically, 89.95 to 98.5 weight percent of polypropylene polymer having long branches introduced, 1 to 10 weight percent of acrylic polytetrafluoroethylene, and antioxidant It is characterized by including 0.05 to 0.5% by weight.

Highly elastic polypropylene, prepolymerized, acrylic polytetrafluoroethylene

Description

High elastic polypropylene resin composition {COMPOSITION FOR PRODUCING HIGH MELT STRENGTH POLYPROPYLENE}

The present invention relates to a polypropylene resin composition having excellent vacuum formability and high elasticity, wherein the composition comprises 89.95 to 98.5 wt% of a polypropylene polymer having a long branch, 1 to 10 wt% of an acrylic polytetrafluoroethylene, and an antioxidant. It is characterized by including 0.05 to 0.5% by weight.

Since general linear polypropylene has a linear structure, the melt strength is much lower than that of polyethylene, and thus, it is not suitable for product use such as foaming, vacuum thermoforming, extrusion coating, etc. which are processed in the molten state. Two methods have been used to solve this problem. The first is to introduce a long chain branch into the polyolefin, which reduces the attraction between the polymer chains in the processing process and gives easy flow characteristics, and requires molding stability (especially dimensional stability such as large blows). Long branches play a role of increasing high elasticity through physical crosslinking with adjacent chains. In order to prepare a high elastic polyolefin by introducing such long branches, radicals are mainly formed on the polyolefins that have passed through the polymerization reactor through electron beam or reaction extrusion, and then reacted again to form long branches in the chain-type polyolefin. Was used. The second is to physically blend polyethylene into polypropylene with a very low melt index. The second method has a problem that the workability is lowered because the melt index. Therefore, if a polymerization method and a blending method are developed in which a high elasticity polyolefin having a high elasticity useful as a molding material is directly polymerized in the polymerization step, a high elasticity can be further improved, the use of the polyolefin as a molding material can be expected to be expanded.

In order to solve the problems of the prior art as described above, an object of the present invention is to provide a resin composition having a high melt strength and a manufacturing method thereof.

The polypropylene resin composition having excellent vacuum formability and high elasticity according to the present invention contains 89.95 to 98.5% by weight of a long branched polypropylene polymer, 1 to 10% by weight of acrylic polytetrafluoroethylene and 0.05 to 0.5% by weight of antioxidant. It is characterized by including.

In addition, the present invention is excellent in vacuum formability, characterized in that the polypropylene polymer having the long branch introduced is polymerized or copolymerized in the presence of a catalyst comprising the following (a), (b) and (c) It relates to a high elastic polypropylene resin composition:

(a) surface-treating the solid titanium catalyst for olefin polymerization including a magnesium compound, a titanium compound and an electron donor with a silane compound having two or more double bonds, and then prepolymerizing the olefin monomer and diene compound to the surface-treated catalyst. Prepolymerization catalyst obtained by the;

(b) organometallic compounds of Group I or Group III metals of the periodic table; And

(c) External Electron Donors.

As the solid titanium catalyst used in the preparation of the prepolymerization catalyst (a) of the present invention, any conventional solid titanium catalyst for olefin polymerization may be used, which may be prepared by various methods. For example, a magnesium compound having no reducing ability in liquid state in the presence of an electron donor without active hydrogen may be prepared by direct contact reaction with liquid titanium compound, that is, by directly contacting each other in liquid state. It is also possible to obtain a solid catalyst from a magnesium compound and a titanium compound without contacting an electron donor, without an electron donor having no active hydrogen.

Among the various methods of preparing the solid titanium catalyst used in the preparation of the prepolymerization catalyst of the present invention, the most common method is to contact a magnesium compound with a titanium compound containing at least one halogen and, if necessary, the product. Various methods of treating with an electron donor are known. Some of these methods are described in JP 2,230,672, 2,504,036, 2,553,104 and 2,605,922 and JP 51-28189, 51-136625 and 52-87486. . Further, a method for producing a solid titanium compound containing an electron donor from a liquid magnesium compound and a liquid titanium compound is disclosed in Japanese Patent Laid-Open No. 79-40293.

In addition, as a solid titanium catalyst used in the preparation of the prepolymerization catalyst of the present invention, U.S. Patent Nos. 4,482,687, 4,277,372, 3,642,746, 3,642,772, 4,158,642, 4,148,756, 4,477,639, and Conventional Ziegler-Natta catalysts described in 4,518,706, 4,946,816, 4,866,022, 5,013,702, 5,124,297, 4,330,649, European Patent 131,832, and Japanese Patent Laid-Open No. 63-54004 and the like can be used.

Preferred one of the method for producing a solid titanium catalyst is as follows, in the embodiment of the present invention was used to prepare a magnesium-supported solid complex titanium catalyst in this way. In other words,

(i) dissolving a non-reducing magnesium compound in an electron donor to prepare a magnesium compound solution, and (ii) reacting the magnesium compound solution with a transition metal compound, a silicon compound, a tin compound, or a mixture thereof to precipitate solid particles. Next, (iii) the precipitated solid particles were reacted with the titanium compound and the electron donor, and washed with a hydrocarbon solvent to prepare solid catalyst particles having a controlled particle shape.

Non-reducing magnesium compounds used in the preparation of such solid titanium catalysts include magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide and magnesium fluoride; Alkoxymagnesium halides such as methoxymagnesium chloride, ethoxymagnesium chloride, isopropoxymagnesium chloride, butoxymagnesium chloride and octoxymagnesium chloride; Aryloxymagnesium halides such as phenoxyshimamium chloride and methylphenoxy magnesium chloride; Alkoxy magnesium such as ethoxy magnesium, isopropoxy magnesium, butoxy magnesium and octoxy magnesium; Aryloxymagnesiums such as phenoxyshimamium and dimethylphenoxy magnesium; Or magnesium salts of carboxylic acids such as magnesium lauryl and magnesium stearate.

Such magnesium compound may be used in the form of a complex with another metal or in combination with another metal, or may be used as a mixture of two or more magnesium compounds. Preferred magnesium compounds are hydrogen-containing magnesium compounds, magnesium chloride, alkoxymagnesium chlorides, preferably those having C ₁ to C ₁₄ alkoxy and aryloxymagnesium chlorides, preferably C ₅ To C ₂₀ aryloxy group.

Usually, the above-listed compounds may be represented by simple chemical formulas, but sometimes they may not be expressed by simple formulas depending on the preparation method of the magnesium compound. These are generally regarded as mixtures of the aforementioned compounds. For example, a method of reacting magnesium metal with an alcohol or phenol in the presence of halosilane, phosphorus pentachloride or thionyl chloride, and pyrolysis of Grignard reagent or hydroxyl group, carbonyl group ester bond, ether bond or the like Compounds obtained by the decomposition method are regarded as a mixture of various compounds according to the reagents or reactivity, and these compounds may also be used in the present invention.

The magnesium compound solution is prepared by reacting the aforementioned magnesium compound with at least one electron donor selected from the group consisting of alcohols, organic carboxylic acids, aldehydes, amines and mixtures thereof in the presence or absence of a hydrocarbon solvent. Magnesium compound solutions can be prepared by mixing and heating a hydrocarbon solvent and an electron donor. Examples of hydrocarbon solvents used for these purposes include aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane, dodecane and kerosene; Alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane and methylcyclohexane; Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene and cymene; And halogenated hydrocarbons such as dichloroethane, dichloropropane, dichloroethylene, trichloroethylene, carbon tetrachloride and chlorobenzene.

In the case of dissolving the hydrogen-containing magnesium compound in the hydrocarbon solvent using alcohol as an electron donor in the preparation of the magnesium compound solution in step (iii), the amount does not vary depending on the amount and type of the magnesium compound and the hydrocarbon solvent. However, it is preferred to use a minimum amount of alcohol per mole of magnesium compound, preferably about 1.0 to 20 moles, more preferably about 2.0 to about 10 moles.

When aliphatic hydrocarbons or cycloaliphatic hydrocarbons are used as the hydrocarbon solvent, the alcohols are used in the above-mentioned amounts, but when using alcohols having 6 or more carbon atoms among these alcohols, at least 0.5 mole per mole of magnesium compound, preferably When 1.0 mol or more is used, the halogen-containing magnesium compound may be dissolved, and a catalyst component having high activity may be obtained by using a small amount of alcohol. In this case, when only alcohols having 5 or less carbon atoms are used, the total amount of alcohol should be at least about 15 moles per mole of halogen-containing magnesium compound, and the resulting catalyst component also has lower catalytic activity than when alcohol is used in the above-described method. On the other hand, when an aromatic hydrocarbon is used as the hydrocarbon solvent, the hydrogen-containing magnesium compound can be dissolved by using about 20 moles, preferably about 1.5 to 12 moles of alcohol, regardless of the type of alcohol.

The contact reaction between the magnesium compound and the alcohol which is the electron donor is preferably carried out in a hydrocarbon medium. The contact reaction is about 15 minutes to about 5 hours, preferably about 30 minutes to about room temperature or high temperature, for example, about 30 to 200 ° C, preferably about 60 to 150 ° C, depending on the type of magnesium compound and alcohol. It is carried out for 3 hours.

Alcohols used as electron donors in step (iii) include 2-methylpentanol, 2-ethylbutanol, n-heptanol, n-octanol, having at least 6 carbon atoms, preferably 6 to 20 carbon atoms, Aliphatic alcohols such as 2-ethylhexanol, decanol, dodecanol, tetradecyl alcohol, undecenol, oleyl alcohol and stearyl alcohol; Alicyclic alcohols such as cyclohexanol and methylcyclohexanol; And aromatic alcohols such as benzyl alcohol, methyl benzyl alcohol, isopropylene benzyl alcohol, α-methylbenzyl alcohol and α, α-dimethylbenzyl alcohol. Alcohols having 5 or less carbon atoms include methanol, ethanol, propanol, butanol, ethylene glycol and methylcarbitol.

In the case of preparing the magnesium compound solution in the step (i), in addition to the above compounds, various compounds described in the known literature may be added to improve the properties of the catalyst or the properties of the polymer to be produced. For example, compounds such as aluminum halides, organic silane compounds or phosphorus compounds may be further included.

In the step (ii), the magnesium compound solution prepared as described above is reacted with a transition metal compound such as a titanium compound, a silicon compound, a tin compound or a mixture thereof to crystallize into a spherical solid. At this time, the amount of the transition metal compound and the like can be added as appropriate. For example, an appropriate amount of the transition metal compound, silicon compound, tin compound, or a mixture thereof per mole of magnesium compound is 0.1 to 20 moles, preferably 0.1 to 10 moles, more preferably 0.2 to 2 moles. .

When the liquid magnesium compound is crystallized in step (ii), the shape and size of the magnesium carrier vary depending on the reaction conditions, and the preferred contact reaction temperature is in the range of about -70 ° C to 200 ° C. In general, however, in order to obtain the form of granular or spherical particles, it is preferable to avoid high temperatures during mixing, and if the contact temperature is too low, precipitation of the solid product does not occur, so this reaction is carried out at a temperature of about 20 ° C to 150 ° C. It is desirable to.

In the step (iii), the magnesium compound in the solid particle state obtained above is reacted with a titanium compound and an electron donor to prepare a solid complex titanium catalyst. Examples of electron donors used in this step are generally oxygen-containing electron donors such as water, alcohols, phenols, ketones, aldehydes, carboxylic acids, esters, ethers and acid amides, and ammonia, amines and nitriles. And nitrogen-containing electron donors such as isocyanates, specific examples of which include methanol, ethanol, propanol, pentanol, hexanol, octanol, dodecanol, octadecyl alcohol, benzyl alcohol, phenylethyl alcohol, cumyl alcohol and the like. Alcohols containing 1 to 18 carbon atoms, such as propylbenzyl alcohol, and 6 to 15 carbon atoms, which may contain lower alkyl groups such as phenol, cresol, xylene, ethylphenol, propylphenol, cumylphenyl and naphthol Ketones to be contained, such as acetaldehyde, propionaldehyde, octyl aldehyde, benzaldehyde, tolualdehyde and naphthol aldehyde Aldehydes containing 2 to 15 carbon atoms, methyl formate, methyl acetate, ethyl acetate, vinyl acetate, propyl acetate, octyl acetate, cyclohexyl acetate, ethyl propionate, methyl butyrate, ethyl valeric acid, methyl chloroacetate, dichloro Ethyl acetate, methyl methacrylate, ethyl crotonate, ethyl cyclohexanecarboxylic acid, phenyl benzoate, benzyl benzoate, methyl toluate, ethyl toluate, amyl toluate, ethyl ethyl benzoate, methyl aniseate, aniseic acid Ethyl, ethyl ethoxybenzoate, γ-butyrolactone, δ-valerolactone, coumarin, phthalide, cyclohexyl acetate, ethyl propionate, methylbutyrate, methylbarate, methylchloroacetate, ethyldichloroacetate, methylmetha Acrylate, ethylcycloate, phenylbenzoate, methyltoluate, ethyltoluate, propylbenzoate, butylbenzoate, cyclohexylbenzoate Organic acid esters containing 2 to 18 carbon atoms, such as sodium, amyltoluate, ethylene carbonate and ethylene carbonate, and 2 to 15 carbon atoms, such as acetyl chloride, benzyl chloride, toluic acid and Acid halides to be contained, acid amides such as methyl ether, ethyl ether, isopropyl ether, butyl ether, amyl ether, tetrahydrofuran, anisole and diphenyl ether, methylamine, ethylamine, diethylamine, Containing amines such as tributylamine, piperidine, tribenzylamine, aniline, pyridine, pinolin and tetramethylethylenediamine, nitriles such as acetonitrile, benzonitrile and tolunitrile and the aforementioned functional groups in the molecule There are compounds such as aluminum, silicon and tin. Also as ester derivatives of monoethylene glycol (MEG), diethylene glycol (DEG), triethylene glycol (TEG), polyethylene glycol (PEG), monopropylene glycol (MPG) and dipropylene glycol (DPG) acetate, propionate , n- and iso-butyrate, benzoate, toluate and the like may be preferably used. Examples of the benzoate include monoethylene glycol monobenzoate, monoethylene glycol dibenzoate, diethylene glycol monobenzoate, Diethylene glycol dibenzoate, triethylene glycol monobenzoate, triethylene glycol dibenzoate, monopropylene glycol monobenzoate, dipropylene glycol monobenzoate, dipropylene glycol dibenzoate, tripropylene glycol monobenzoate, and the like. have. These electron donors can be used as mixtures of two or more, with aromatic esters in particular being suitable. However, such electron donors are not always necessary as starting materials and may be used in the form of adducts or complexes of other compounds. The amount of the electron donor can be appropriately changed, and it is preferable to use about 0.01 to about 10 moles, preferably about 0.01 to 5 moles, more preferably 0.05 to about 1 mole per mole of magnesium compound.

The liquid titanium compound to be reacted with the magnesium compound in the solid particle state in step (iii) is a _tetravalent titanium compound having the general formula Ti (OR) _m X _4-m (wherein R is an alkyl group having 1 to 10 carbon atoms, X Represents a halogen atom, and m is a number of 0 ≦ m ≦ 4). Examples of such titanium compounds include titanium tetrahalides such as TiCl ₄ , TiBr ₄ and TiI ₄ ; Ti (OCH ₃ ) Cl ₃ , Ti (OC ₂ H ₅ ) Cl ₃ , Ti (OC ₄ H ₉ ) Cl ₃ , Ti (OC ₂ H ₅ ) Br ₃ and Ti (O (iC ₂ H ₅ )) Br ₃ Halogenated alkoxytitanium such as titanium; Dihalogenated alkoxytitanium such as Ti (OCH ₃ ) ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ , Ti (OC ₄ H ₉ ) ₂ Cl ₂ and Ti (OC ₂ H ₅ ) ₂ Br ₂ ; Monohalogenated alkoxytitanium such as Ti (OCH ₃ ) ₃ Cl, Ti (OC ₂ H ₅ ) ₃ Cl, Ti (OC ₄ H ₉ ) ₃ Cl and Ti (OC ₂ H ₅ ) ₃ Br; And tetraalkoxy titanium mixtures such as Ti (OCH ₃ ) ₄ , Ti (OC ₂ H ₅ ) ₄ , Ti (OC ₄ H ₉ ) _4, and the like. Among these halogen-containing titanium compounds, titanium tetrahalide is preferable, and titanium tetrachloride is particularly preferable among titanium tetrahalide.

Such titanium compounds are used in an amount of at least 1 mole, typically 3 to about 200 moles, preferably about 5 to 100 moles, per mole of magnesium compound. When contacting the magnesium compound with the liquid titanium compound, it is advisable to mix at a low temperature and then slowly increase the reaction temperature. For example, the two compounds are brought into contact with each other at -70 ° C to about 50 ° C to prevent them from reacting rapidly.The reaction is slowly raised to a sufficient time at a temperature of 50 to 150 ° C, and then the product is used in a polymerization reaction. Wash with free hydrocarbons until no free titanium is detected. By such a catalyst preparation method, a solid titanium catalyst having excellent performance can be prepared.

The solid titanium catalyst used in the present invention preferably has a molar ratio of halogen / titanium of about 4 or more and substantially does not liberate the titanium compound by hexane washing at room temperature. Preferred examples of solid titanium catalysts are those in which the molar ratio of halogen / titanium is at least about 4, more preferably at least about 5, most preferably at least about 8, and the molar ratio of magnesium / titanium is at least about 3, preferably from about 5 to And a molar ratio of electron donor / titanium is from about 0.2 to about 6, preferably from about 0.4 to about 3, more preferably from about 0.8 to about 2. Furthermore, the specific surface area of the solid is at least 10 m 2 / g, preferably at least about 50 m 2 / g, more preferably at least 100 m 2 / g. It is preferable that the X-ray spectrum of the solid titanium catalyst exhibits amorphous properties irrespective of the starting magnesium, or is more amorphous than the commercial grade of conventional magnesium halides.

In the step (iii) of the present invention, when the magnesium compound in the solid particle state and the titanium compound in the liquid state are reacted, various compounds described in a known document may be further included in addition to the electron donor. For example, a compound having a phthalic group may be included. By adding such additional compounds, it is also possible to control the particle distribution of the polymer having high catalytic activity or produced.

In order to prepare the prepolymerization catalyst (a) used in the production of the polypropylene polymer in which the long branch of the present invention is introduced, the above-mentioned solid complex titanium catalyst is first surface treated with a silane compound having two or more vinyl groups. Divinyl silane compounds, divinyl diphenyl silane, divinyl diethyl silane, divinyl diisobutyl silane, divinyl dihydride silane, etc. are mentioned as a divinyl silane compound used at this time. In the case of surface treatment, these materials use an amount of 2 to 200 moles per mole of magnesium compound. The reaction of the solid titanium catalyst with these surface treatment materials is brought into contact by contacting the two compounds between -70 and 50 ° C., where both materials can be reacted with or without a solvent.

In order to prepare the prepolymerization catalyst used in the preparation of the polypropylene polymer of the present invention, prepolymerization is performed on the surface-treated solid titanium catalyst as described above. In the prepolymerization process, when the olefin monomer and the diene compound are reacted at -50 to 50 ° C. in the presence of the surface-treated solid titanium catalyst and alkyl aluminum and electron donor, the double bond compounds and olefin monomer surface-treated on the catalyst and The diene compounds react together to polymerize high molecular weight monomers on the surface of the catalyst. These high molecular weight monomers consist of olefins, double bond-containing silane-based materials and dienes, which encapsulate the catalyst surface. The composition of the olefin, diene, and silane-based materials in the high molecular weight monomer thus produced is 1 to 99% by weight of olefin, 0.01 to 10% by weight of diene, and 0.001 to 1% by weight of silane material. Among these, it is preferable that 70 to 95 weight% of olefins, 0.1 to 5 weight% of dienes, and 0.01 to 1 weight% of silane materials. In this case, at least one selected from ethylene, propylene, 1-butene, 1-hexene, and 1-octene is used as the olefin monomer, and as the diene-based material, 1,3-butadiene, 1,5-hexadiene, 1,7-octadiene, 1,9-decadiene, 1,13- tetradecadiene, etc. are mentioned.

The high molecular weight monomer polymerized around the catalyst reacts with the propylene monomer in the present polymerization to form a long chain branch or network. The molecular weight of this high molecular weight monomer is preferably in the range of 500 to 100,000, and among these, the polymer having excellent polymerization capacity in the present polymerization is in the range of 1,000 to 10,000 molecular weight.

The prepolymerization catalyst of the present invention prepared as above is advantageous for the polymerization of olefins such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, vinylcycloalkane or cycloalkene Used. In particular, these catalysts are suitable for the polymerization of α-olefins having three or more carbon atoms, copolymerization of each other, copolymerization thereof with less than 20 mol% of ethylene, and those having polyunsaturated compounds such as conjugated or nonconjugated dienes. It is advantageously applied to the copolymerization of.

Examples of the organometallic compound (b) used in the preparation of the polypropylene polymer having the long branch of the present invention include trialkylaluminum such as triethylaluminum and tributylaluminum; Trialkenyl aluminum, such as triisoprenyl aluminum, partially alkoxylated alkyl aluminum, for example dialkyl aluminum alkoxide, such as diethyl aluminum ethoxide and dibutyl aluminum butoxide, ethyl aluminum sesquiethoxy Alkyl aluminum sesquihalides such as seed and butylaluminum sesquiethoxides and alkylaluminum dihalides such as ethylaluminum dichloride, propylaluminum dichloride and butylaluminum dibromide, partially halogenated aluminum, for example diethylaluminum Aluminum hydrides such as hydride or dibutylaluminum hydride and dialkylaluminum hydrides such as dibutylaluminum hydride, partially alkoxy such as ethylaluminum ethoxychloride, butylaluminum butoxychloride and ethylaluminum ethoxybromide Chemistry and belongs to the halogenated alkyl aluminum.

The external electron donor (c) used in the preparation of the polypropylene polymer having the long branches of the present invention may use an external electron donor material commonly used for olefin polymerization. These external electron donors are mainly used to optimize the activity and stereoregularity of the catalyst in the polymerization of olefins. Examples of external electron donors usable in the present invention include organic acids, organic acid anhydrides, organic acid esters, alcohols, ethers, aldehydes, ketones, silanes, amines, amine oxides, amides, diols, oxygen such as phosphate esters, silicon, nitrogen, sulfur, And organic compounds containing phosphorus atoms and mixtures thereof. Particularly preferred external electron donors are organosilicon compounds with alkoxy groups, i.e., alkoxy silane compounds, and their kinds include aromatic silanes such as diphenyldimethoxysilane, phenyltrimethoxysilane, phenylethyldimethoxysilane and phenylmethyldimethoxysilane. ; Isobutyltrimethoxysilane, diisobutyldimethoxysilane, diisopropyldimethoxysilane, di-t-butyldimethoxysilane, t-butyltrimethoxysilane, cyclohexylmethyldimethoxysilane, dicyclopentyldimethoxy Aliphatic silanes such as silane, dicyclohexyldimethoxysilane, 2-norbornanetriethoxysilane, 2-norbornanemethyldimethoxysilane, vinyltriethoxysilane and silicone tetraethoxide; And mixtures thereof, among which the branched alkyl dialkoxysilanes such as diisobutyldimethoxysilane and cycloalkyl dialkoxysilanes such as dicyclopentyldimethoxysilane are effective among the silane compounds described above. The compounds may be used alone or in combination of two or more thereof.

When the polymerization is carried out in a liquid phase, an inert solvent such as hexane, heptane or kerosene may be used as the reaction medium, but the olefin itself may serve as the reaction medium. In the case of liquid phase polymerization, the preferred concentration of the prepolymerization catalyst (a) in the polymerization reaction system is from about 0.001 to about 5 mmol, preferably from about 0.001 to about 0.5 mmol, based on titanium atoms per liter of solvent. In the case of gas phase polymerization, the amount of the prepolymerization catalyst (a) is about 0.001 to about 5 mmol, preferably about 0.001 to about 1.0 mmol, more preferably 0.01 to about 0.5, based on titanium atoms, per liter of the polymerization zone. It is good to set it as mmol. In addition, the ratio of organometallic atoms in component (b) is preferably about 1 to 2,000 mol, preferably about 5 to 500 mol, per mole of titanium atoms in catalyst (a), and the proportion of external electron donor component (c) is nitrogen. Or about 0.001 to 10 mol, preferably about 0.01 to 2 mol, particularly preferably 0.05 to 1 mol per mole of organometallic atom in component (b) on a silicon atom basis.

The polymerization or copolymerization reaction of the polypropylene polymer with the long branch of the present invention proceeds in the same manner as in the polymerization using a conventional Ziegler-type catalyst. In particular, it is carried out substantially in the absence of oxygen and water. The polymerization of the olefins may preferably be carried out at a temperature of about 20 to 200 ° C., more preferably at a temperature of about 50 to 180 ° C. and a pressure of atmospheric pressure to 100 atmospheres, preferably at a pressure of about 2 to 50 atmospheres. This polymerization can be carried out batchwise, semibatch or continuously, and it is also possible to carry out the polymerization in two or more stages with different reaction conditions.

The resin composition of the present invention is 89.95 to 98.5% by weight of polypropylene polymer polymerized using the above prepolymerization catalyst, 1 to 10% by weight of acrylic polytetrafluoroethylene and 0.05 to 0.5% by weight of antioxidant Is done.

The melt index of the polypropylene with long branches used in the present invention is 0.1-20 g / 10 min (ASTM D1238: 230 ° C., 2.16 kg), preferably 0.3-5 g / 10 min. If the melt index of the polypropylene polymer having long branches is less than 0.1 g / 10 minutes, processing is disadvantageous due to low flowability, and if it exceeds 20 g / 10 minutes, the sheet sags during processing.

In the present invention, the content of the acrylic polytetrafluoroethylene is preferably 1 to 10% by weight. If it is less than 1% by weight, the thermal deflection characteristics, the melt strength or the elastic force does not increase, and if it exceeds 10% by weight, the thermal deflection characteristics, the melt strength or the elastic force, etc. are not increased any more, but the manufacturing cost rises and heat resistance is poor. There is a problem.

In the resin composition of the present invention, the antioxidant is added to prevent polymer chain scission induced by polymer deterioration and oxidation. Preferably, tetrakis [methylene (3,5-di-tert-) is added. Compounds such as butyl-4-hydroxyhydrocinnamate] methane (Tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate] methane) may be advantageously used. The antioxidant content is 0.05% by weight. If less than%, it is difficult to expect the anti-oxidation performance due to deterioration of the polymer, if it exceeds 0.5% by weight, the effect is no longer increased compared to the amount of antioxidant added, there is a problem of an increase in manufacturing cost according to the increase.

Various additives such as heat stabilizer, nucleating agent, weather stabilizer, antistatic agent, lubricant, slip agent, flame retardant, pigment or dye may be added to the resin composition of the present invention as needed in addition to the above-described compounds, which can be sufficiently predicted by those skilled in the art. It is.                     

In the present invention, there is no particular limitation on the method of blending the polymer having the long branches introduced with the acrylic polytetrafluoroethylene, and a commonly known blending method may be used. Each of the above components and other additives may be added in the required amount to knead using a kneader such as a kneader, roll, and Bambury mixer and a single or twin screw extruder.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, these examples are for illustrative purposes only and the scope of the present invention is not limited to these examples.

Example

Example 1

Preparation of Prepolymerization Catalyst (a)

Step 1: Preparation of Magnesium Compound Solution

Into a 1.0 liter reactor equipped with a mechanical stirrer replaced with a nitrogen atmosphere, a mixture of 15 g of MgCl ₂ , 4.2 g of AlCl ₃ and 550 ml of toluene was added and stirred at 400 rpm, followed by 30 ml of tetrahydrofuran, 28 ml of butanol and 1.4 ml of ethanol. , 1.5 ml of silicon tetraethoxide and 3.0 ml of tributyl phosphate were added thereto, and the temperature was raised to 105 ° C. for 4 hours. The homogeneous solution obtained after the reaction was completed was cooled to room temperature.

Step 2: preparing a solid carrier

The magnesium solution prepared in step 1 was transferred to a 1.6 liter reactor maintained at 13 ° C. After stirring was maintained at 350 rpm, 15.5 mL of TiCl ₄ was added thereto, and the temperature of the reactor was raised to 90 ° C. Solid carriers were produced during this process. The reaction was continued at 90 ° C. for 1 hour and then stirring was stopped to allow precipitation of the resulting solid support. After the precipitation was completed, the solid carrier from which the supernatant was separated was washed twice with 75 ml of toluene.

Step 3: Preparation of Solid Titanium Catalyst

100 mL of toluene and 100 mL of TiCl _{4 were} added to the solid carrier, and the temperature of the reactor was raised to 110 ° C. and heated for 1 hour. After the stirring was stopped, the solid carrier was precipitated, the supernatant was separated, 100 ml of toluene and 100 ml of TiCl ₄ were added thereto, and 2.9 ml of diisobutyl phthalate was added at 70 ° C. The temperature of the reactor was again raised to 120 ° C. and stirred for 1 hour. After the stirring was stopped, the supernatant was separated, 100 ml of toluene was injected, and the temperature of the reactor was lowered to 70 ° C. and stirred for 30 minutes. After the reactor was stopped and the supernatant was separated, 100 ml of TiCl ₄ was injected and stirred at 70 ° C. for 30 minutes to prepare a solid titanium catalyst.

Step 4: surface treatment of solid titanium catalyst

The solid titanium catalyst prepared above was washed five times with 75 ml of purified hexane, and 500 ml of hexane and 50 ml of divinyldimethyl silane were added and reacted at room temperature for 1 hour.

The prepared catalyst was stored after drying in a nitrogen atmosphere. The surface-treated solid titanium catalyst contained 2.5% by weight of titanium atoms.                     

Step 5: prepolymerization

After washing the high-pressure reactor with a capacity of 0.5 liter with propylene, 2 g of the catalyst obtained in the above step 4, 300 ml of hexane, 6 mmol of triethylaluminum, and 20 ml of hexadiene were added, and the pressure was adjusted to 0.9 atm with ethylene, at 20 ° C. The polymerization was carried out for 5 hours. In the prepolymerization catalyst thus obtained, the amount of the high molecular weight monomer polymerized around the catalyst was 31.0 g per 1 g of the catalyst.

polymerization

     A 2 liter high pressure reactor was rinsed with propylene and then loaded into a reactor containing 20 mg of the prepolymerized catalyst prepared above in a glass bottle, and then the reactor was repeated three times in a nitrogen / vacuum state and brought to atmospheric pressure. 7 mmol of triethylaluminum, 0.5 mmol of dicyclopentyldimethoxysilane and 0.5 mmol of diisopropyldimethoxysilane were injected into the reactor. Again, 5,000Nml of hydrogen was added, and then 1,200ml of liquid propylene was added, and then the temperature was raised to 65 ° C while the reactor was stirred, and polymerization was performed for 1 hour. After the polymerization reaction was completed, the unreacted gas was discharged, the temperature was cooled to room temperature, and the reactor was desorbed. The resulting polymer was collected separately and dried in a vacuum oven at 50 ° C. for at least 6 hours to obtain a white polymer.

Blending

4.55 g (4.55 wt%) of acrylic polytetrafluoroethylene was added to 94.95 g (94.95 wt%) of a polypropylene polymer having a melt index of 8 g / 10 min (ASTM D1238: 230 ° C., 2.16 kg) in which the long branches were introduced. As antioxidant, 0.5 g (0.5% by weight) of tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate] methane was granulated into pellets through a twin screw extruder.

Heat sagging evaluation (Heat sagging characteristic)

     The resin composition in the form of pellets was molded into a sheet having a thickness of 0.5 mm using a casting apparatus in the form of a T die. As a method for evaluating the vacuum thermoforming of the molded sheet, the length of the sheet was sag after 60 seconds in an oven at 170 ° C. after mounting the sheet between two 15 cm diameter discs.

Melt strength measurement

Blending the polypropylene polymer and the acrylic polytetrafluoroethylene prepared in the above process by measuring the melt strength of the strand exiting the die of the extruder (blabender) at 220 ° C. using Leotens (manufactured by Göttingert, Germany) Melt strength of the resin composition was measured, and the results are shown in Table 1 below. The die diameter at the time of the measurement was 2 mm, and the distance from the die inlet to the rhetens roller was 10 cm.

Elastic force measurement (die swell ratio)

The die swell ratio (hereinafter referred to as DSR) is calculated by measuring the diameter (D2) of the melt after passing through an orifice having a diameter (D1) of 2 mm in the melt index measuring device.

       DSR = D2 / D1

Comparative Example 1

The sheet was molded in the same manner as in Example 1, except that 98 wt% of the polypropylene polymer having long branches and 2 wt% of the acrylic polytetrafluoroethylene were added and no antioxidant was added. The results are shown in Table 1.

Comparative Example 2

The sheet was molded in the same manner as in Example 1, except that 90 wt% of the polypropylene homopolymer polymerized without undergoing the prepolymerization process of the polymer monomer was used instead of the polymer in which the branch was introduced. The results are shown in Table 1.

Comparative Example 3

Antioxidant tetrakis [methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate] methane to 99.5% by weight of polypropylene polymer with long branches introduced without blending acrylic polytetrafluoroethylene The sheet was molded in the same manner as in Example 1 except that 0.5 wt% was used, and the results are shown in Table 1.

Table 1. Results of Polymerization

Polymerization Activity (kg-PP / g-cat) Melt Index (MI) (g-PP / 10min) Melt strength (mN) Sagging length after 60 seconds in the oven D.S.R Example 1 35 7.5 300 0.5cm 3.5 Comparative Example 1 35 12 100 2.5cm 2.7 Comparative Example 2 35 8 150 2 cm 1.5 Comparative Example 3 35 8 50 5 cm 2.2

As can be seen from the above examples and comparative examples, by blending the polypropylene polymer and the acrylic polytetrafluoroethylene polymerized using the prepolymerization catalyst, the elastic force, the thermal sag phenomenon and the melt strength of the resin composition were measured. It can be seen that the results are greatly increased.

According to the resin composition which concerns on this invention, the high elastic polypropylene resin composition suitable for use in the vacuum thermoforming process processed in a molten state can be provided.

Claims (3)

89.95 to 98.5 weight percent of polypropylene polymer with long branches introduced, 1 to 10 weight percent of acrylic polytetrafluoroethylene and 0.05 to 0.5 weight percent antioxidant, wherein the polypropylene polymer with long branches introduced is Highly elastic polypropylene resin composition having excellent vacuum formability, characterized in that it is polymerized or copolymerized in the presence of a catalyst comprising (a), (b) and (c): (a) surface-treating a solid titanium catalyst for olefin polymerization comprising a magnesium compound, a titanium compound, and an electron donor with a silane compound having two or more double bonds, and then prepolymerizing the olefin monomer and diene compound to the surface-treated catalyst. Prepolymerization catalyst obtained by the; (b) organometallic compounds of Group I or Group III metals of the periodic table; And (c) External Electron Donors. delete The polypropylene polymer having excellent vacuum formability and high elasticity according to claim 1, wherein the polypropylene polymer into which the long branch is introduced has a melt index of 0.1 to 20 g / 10 minutes (ASTM D1238: 230 ° C, 2.16 kg). Composition.