JPH05214177A - Polyolefin resin composition having excellent stability - Google Patents

Abstract

PURPOSE:To obtain the subject composition resistant to the yellowing in storage caused by the action of light, oxygen, etc., and the deterioration in heating and having reduced metal corrosivity by adding a specific phosphorus compound, a hydrotalcite and a fatty acid metal salt, etc., to a polyolefin resin. CONSTITUTION:The objective polyolefin resin composition having improved stability is produced by compounding a polyolefin resin (e.g. ethylene.1-butene copolymer resin) with (A) one or more kinds of phosphorus compounds expressed by formula I [R5 to R7 are H, hydrocarbon group such as alkyl, cycloalkyl, aryl and alkenyl or oxygen-containing hydrocarbon group such as hydroxyl group, ether group and epoxy group) or formula II (R4 and R5 are hydrocarbon group or oxygen-containing hydrocarbon group; (n) is integer of 1-3), (B) a hydrotalcite, (C) a compound such as a fatty acid metal salt, a hydroxyfatty acid metal salt and a fatty acid and (D) a hindered phenolic antioxidant and/or a thioether-type antioxidant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin resin composition, and more particularly, to a composition obtained by adding a specific phosphorus compound and an acid absorbent to a polyolefin resin, or a phenolic antioxidant and / or a thioether oxide. The present invention relates to a polyolefin composition having improved color stability, heat stability and corrosion resistance obtained by adding an inhibitor.

[0002]

Polyolefins such as polyethylene and polypropylene are generally relatively inexpensive and have excellent mechanical properties, so that they are used for the production of various molded products such as injection molded products, hollow molded products, sheets and films. There is. However, these polyolefins are deteriorated by a chemical action such as heat and oxygen and a mechanical action such as a shearing force at the time of molding process, and coloring and mechanical strength are lowered, and they cannot be used. Therefore, various antioxidants have been widely used for the purpose of preventing thermal deterioration during molding, but polyolefins containing these additives, especially phenolic antioxidants, are stored for a long time. Then it has the drawback of turning yellow. In recent years, polyolefins have been produced by a process using a highly active catalyst and omitting the catalyst removal step, but it is said that the catalyst residue promotes deterioration of the thermal stability, color, weather resistance and the like of the product polymer. ing.

A method of adding a phosphorus-containing compound such as phosphite has been proposed for the purpose of preventing deterioration of the quality of a polyolefin molded product having such various characteristics. (For example, JP-B-59-21343, JP-A-62-4344.
2, Japanese Patent Publication No. 62-4418). However, phosphorus compounds having good antioxidative properties are still insufficient, such as being liable to absorb moisture, being difficult to handle, and being liable to cause metal corrosion, and thus have been desired to be improved.

[0004]

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a polyolefin composition in which yellowing during long-term storage due to a chemical action of light, oxygen and the like and deterioration during heating are prevented, and metal corrosivity is reduced. To aim.

[0005]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors to solve the above-mentioned problems, the polyolefin resin is represented by the following general formula (I) or (II). Addition of one or more phosphorus compounds and one or more of hydrotalcites, optionally a fatty acid metal salt, a hydroxy fatty acid metal salt, and a fatty acid to improve heat resistance and yellowness during long-term storage. It has been found that an extremely excellent polyolefin resin composition such as deterioration prevention and metal corrosion prevention can be obtained.

That is, the present invention provides a polyolefin resin composition having improved stability, wherein the polyolefin resin contains one or more of the following phosphorus compounds and hydrotalcite. ..

General formula (I):

[Chemical 4]

[Wherein R ₁ , R ₂ and R ₃ are the same or different hydrogen, hydrocarbon group or oxygen-containing hydrocarbon group, respectively] Provided that at least one of R ₁ , R ₂ and R ₃ is

[0009]

[Chemical 5]

-(C _{PH 2 P} O) _q -Z ₃ or -Z
_4- OC _r H _{2r + 1} (where Z
₃ is a group having hydrogen or alkyl, cycloalkyl or aryl, and Z ₄ is a group having an arylene group. p and q are integers of 2-9, r is an integer of 1-10. ). ]

General formula (II): wherein R ₄ and R ₅ have the same or different hydrocarbon groups or oxygen-containing hydrocarbon groups. n is an integer of 0-3. ]

The present invention will be described more specifically. The polyolefin of the present invention means ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene-1, 1
-Α-olefin homopolymers such as octene or interpolymers thereof, ethylene-vinyl ester copolymers such as ethylene-vinyl acetate copolymers, ethylene-unsaturated carboxylic acid or its derivative copolymers or mixtures thereof At least one olefin polymer selected from the group consisting of, but not particularly limited to, when using a polyolefin which is polymerized with a Ziegler high activity catalyst and has not undergone a catalyst removal step. It shows a remarkable effect.

In the present invention, the Ziegler type high activity catalyst is composed of a solid catalyst component containing at least magnesium and titanium and an organic aluminum compound. As the solid catalyst component, metal magnesium; magnesium hydroxide; magnesium oxide; magnesium salts such as magnesium chloride; silicon, aluminum, calcium; double salts and double oxides containing elements selected from magnesium, magnesium carbonate and magnesium atoms, Carbonates, chlorides,
Alternatively, hydroxides and the like; further, these inorganic solid compounds containing an oxide-containing compound, a sulfur-containing compound, an aromatic hydrocarbon,
Examples thereof include those obtained by supporting a titanium compound by a known method on an inorganic solid compound containing magnesium such as one treated or reacted with a halogen-containing substance.

Examples of the above oxygen-containing compounds include water; organic oxygen-containing compounds such as alcohols, phenols, ketones, aldehydes, carboxylic acids, esters, polysiloxanes and acid amides; inorganic substances such as metal alkoxides and metal oxychlorides. Examples of the system oxygen-containing compound can be given.

Examples of the sulfur-containing compound include organic compounds such as thiol and thioether, sulfur-containing compound, and inorganic sulfur compounds such as sulfur dioxide, sulfur trioxide and sulfuric acid. Examples of aromatic hydrocarbons include various monocyclic and polycyclic and polycyclic aromatic hydrocarbon compounds such as benzene, toluene, xylene, anthracene, and phenanthrene. Examples of the halogen-containing substance include compounds such as chlorine, hydrogen chloride, metal chlorides and organic halides. On the other hand, examples of the titanium compound supported on the inorganic solid compound containing magnesium include titanium halides, alkoxy halides, alkoxides, and halogenated oxides. As the titanium compound, a tetravalent titanium compound and a trivalent titanium compound are preferable, and as the tetravalent titanium compound, specifically, a general formula Ti (OR) _n X _4-n (where R is a carbon number 1 To 20 is an alkyl group, an aryl group or an aralkyl group, X is a halogen atom, and n is an integer of 0 ≦ n ≦ 4),
Titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, monomethoxytrichlorotitanium, dimethoxydichlorotitanium,
Trimethoxymonochlorotitanium, tetramethoxytitanium, monoethoxytrichlorotitanium, diethoxydichlorotitanium, triethoxymonochlorotitanium, tetraethoxytitanium, monoisopropoxytrichlorotitanium, diisopropoxydichlorotitanium, triisopropoxymonochlorotitanium, tetraisopropoxytitanium , Monobutoxytrichlorotitanium, dibutoxydichlorotitanium,
Examples thereof include monopentoxytrichlorotitanium, monophenoxytrichlorotitanium and tetraphenoxytitanium. The trivalent titanium compound is obtained by reducing titanium tetrahalide such as titanium tetrachloride and titanium tetrabromide with hydrogen, aluminum, titanium or an organometallic compound of Group I to III metal of the periodic table. Examples include titanium. In addition, the general formula Ti (OR) _m X
_4-m (wherein R represents an alkyl group having 1 to 20 carbon atoms, an aryl group or an aralkyl group, X represents a halogen atom, and m is an integer of O ≦ m ≦ 4) A trivalent titanium compound obtained by reducing halogenated alkoxy titanium with an organometallic compound of a metal of groups I to III of the periodic table can be mentioned.

Of these titanium compounds, tetravalent titanium compounds are particularly preferable. Examples of other catalyst systems include:
As a solid catalyst component, a reaction product of an organomagnesium such as a so-called Grignard compound and a titanium compound can be used.

Another example of the catalyst system is a solid substance obtained by contacting an inorganic oxide such as SiO ₂ or Al ₂ O ₃ as a solid catalyst component with the solid catalyst containing at least magnesium and titanium. It can also be used.

Specific examples of the organoaluminum compound to be combined with the above solid catalyst component include the general formulas R ₃ Al, R ₂ Alx, RAlx ₂ , R ₂ AlOR, R.
An organoaluminum compound of A1 (OR) X and R ₃ Al ₂ X ₃ (wherein R represents an alkyl group having 1 to 20 carbon atoms, an aryl group or an aralkyl group, X represents a halogen atom, and R is the same). May be different), and examples thereof include triethyl aluminum, triisobutyl aluminum, trihexyl aluminum, trioctyl aluminum, diethyl aluminum chloride, diethyl aluminum ethoxide, ethyl aluminum sesquichloride, and mixtures thereof.

The amount of the organoaluminum compound used is not particularly limited, but is usually 0.1 to 1 with respect to the titanium compound.
It can be used in a molar amount of 000. The polymerization reaction is carried out in the same manner as the usual olefin polymerization reaction using a Ziegler type catalyst. That is, all the reactions are carried out in a gas phase or in the presence of an inert solvent or in a liquid phase using the monomer itself as a solvent, in a state where oxygen and water are substantially removed. The polymerization reaction of olefin is carried out at a temperature of 20 to 300 ° C., preferably 4
0 ~ 200 ℃, pressure is normal pressure to 70kg / cm
² G, preferably 2 kg / cm ² G to 60 kg / c
m ² G. The molecular weight can be adjusted to some extent by changing the polymerization conditions such as the polymerization temperature and the molar ratio of the catalyst, but it is effectively performed by adding hydrogen to the polymerization system. Of course, it is possible to carry out a two-step or multi-step multi-step polymerization reaction with different polymerization conditions such as hydrogen concentration and polymerization temperature without any trouble.

The polyolefin used in the present invention is clearly distinguished from a polyolefin obtained by using a conventional solid catalyst component mainly containing vanadium as a solid catalyst component. Even if both have the same monomer constituting the copolymer and have the same density, the _Tm by DSC is higher in the polyolefin of the present invention. In addition, the C ₆ insoluble content is 10% by weight or more in the copolymer of the present invention, whereas when the vanadium-containing catalyst is used, the C ₆ insoluble content is not present or is extremely small.

R ₁ and R in the general formula (I) of the present invention
Examples of the hydrocarbon group represented by ₂ and R ₃ include alkyl, cycloalkyl, aryl, alkylaryl, arylalkyl, alkylalkenylalkyl, and the like, and examples of the oxygen-containing hydrocarbon group include hydroxy group, ether group, and epoxy group. Alternatively, there is a group in which a carbonyloxy group is combined with at least one of the above hydrocarbon groups, for example, alkylepoxyalkyl, alkoxyalkyloxycarbonylalkyl, etc., and at least one of R ₁ , R ₂ and R ₃ is cyclohexylphenyl as described above. It is necessary to be a specific group such as. Representative examples of the organic acid phosphoric acid ester compound represented by the general formula (I) include the following compounds.

[0022]

[Chemical 6]

R ₄ in the general formula (II) of the present invention,
Examples of the hydrocarbon group and oxygen-containing hydrocarbon group of R ₅ are the same as above, and typical examples of these compounds include the following compounds.

[0024]

[Chemical 7]

The composition of the above components used in the present invention is as follows:
0.005-5 with respect to 100 parts by weight of polyolefin
Parts by weight, preferably 0.01 to 2 parts by weight. The hydrotalcites used in the present invention are double salt compounds represented by the following formula.

(M ²⁺ ) _1-x Al _x (OH) ₂ (A ⁿ⁻ ) _{x / n} · mH ₂ O (where 0 <x ≦ 0.5, m: real number M ²⁺ : Mg, Ca or Zn , A ⁿ⁻ : n-valent anion) As this compound, both a natural product and a synthetic product are used, but a synthetic product in which M ²⁺ is Mg and A ⁿ⁻ is CO ₃ ²⁻ is particularly desirable. The composition of the above components used in the present invention is 0.0 based on 100 parts by weight of the polyolefin.
1 to 1 part by weight, preferably 0.02 to 0.08 part by weight. By blending this component, the antioxidant performance is synergistically significantly improved as compared with the addition of the above phosphorus compound alone.

In the present invention, it is preferable to use a fatty acid metal salt, a hydroxy fatty acid metal salt or a fatty acid together. When the fatty acid metal salt, the hydroxy fatty acid metal salt and the fatty acid are exemplified, the fatty acid metal salt is lauric acid or myristin. Acid, palmitic acid, stearic acid, oleic acid,
Examples thereof include salts of fatty acids such as linoleic acid and linolenic acid with metals such as lithium, sodium, magnesium, calcium and zinc, and calcium stearate is particularly preferable. It is also preferable to use a mixture of these metal salts and fatty acids in order to improve color stability, and the mixing ratio is in the range of 2: 8 to 8: 2, preferably 1: 2 to 2: 1. desirable. Examples of the fatty acid include the above fatty acids, and a mixture of stearic acid and calcium stearate is most preferably used. The composition of the above components used in the present invention is 100 parts by weight of the polyolefin,
The amount is 0.05 to 5 parts by weight, preferably 0.1 to 2 parts by weight.

The thermal stability of the composition of the present invention can be further improved by adding a phenol-based antioxidant and / or a thioether-based antioxidant.

Specific examples of the phenolic antioxidant include 2,6-tert-butyl-4-methylphenol and 2-
Tert-Butyl-4-methoxy-phenol, n-octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-ethylidene-bis (2,4-tert-butylphenol ), 4,4'-thiobis (3-methyl-6-tert-butylphenol), 1,
3,5-trimethyl, 2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, Tris (4-tert-butyl-2,
6-dimethyl-3-hydroxybenzyl) isocyanurate, tetrakis- [methylene-3- (3 ', 5'-di-tertiarybutyl) -4'-hydroxy-phenyl) propionate] methane, 3,9-bis [ 1,1-di-methyl-2- {β- (3-tert-butyl-4-hydroxy-5
-Methylphenyl) propionyloxy} ethyl]-
2,4,8,10-Tetraoxazaspiro [5,5] undecane, 4,4'-thio-bis (3-methyl-6-tertiary
Butylphenol). These antioxidants are used by adding 0.01 to 0.15 part by weight.

Examples of thioether type antioxidants include dilauryl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate and dimyristyl-
Examples include 3,3′-thiodipropionate, pentaerythritol-tetrakis- (β-lauryl-thiopropionate), 2-mercapto-5-methylbenzimidazole and the like. These antioxidants are 0.01 to 0.
15 parts by weight are added and used.

The weather resistance of the composition of the present invention can be improved by adding a light stabilizer such as an ultraviolet absorber or a hindered amine compound. Specific examples of the ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone and 2
-Hydroxy-4-octoxybenzophenone, 5,
2-hydroxybenzophenones such as 5'-methylenebis (2-hydroxy-4-methoxybenzophenone),
2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-third
Octylphenyl) benzotriazole, 2- (2-hydroxy-3 ', 5'-ditertiarybutylphenyl) -5-
Chlorobenzotriazole, 2- (2'-hydroxy-
3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2,2'-methylenebis (4-
Benzotriazoles such as tert-octyl-6-benzotriazol) phenol, resorcinol monobenzoate, 2,4-di-tert-butylphenyl-3'-5'-di-tert-butyl-4'-hydroxybenzoate, hexadecyl Examples thereof include benzoates such as -3-5-di-tert-butyl-4-hydroxybenzoate.

The hindered amine light stabilizers include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1. , 2,3,4-butanetetracarboxylate, bis (1,2,2,6,6-
Pentamethyl-4-piperidyl) -di (tridecyl)-
1,2,3,4-butanetetracarboxylate, 1-
Polycondensation product of (2-hydroxyethyl) -2,2,6,6-tetramethyl-4-piperidinol and diethyl succinate, 1,6-bis (2,2,6,6-tetramethyl-4)
-Piperidylamino) hexane and 2,4-dichloro-6
-Polycondensation products of tertiary octylamino-s-triazine and the like.

In addition, heavy metal deactivators, nucleating agents, pigments, fillers, plasticizers, epoxy compounds, foaming agents, antistatic agents, flame retardants, lubricants, processing aids may be added to the composition of the present invention as required. Agents and the like can be included.

[0034]

EXAMPLES AND COMPARATIVE EXAMPLES The present invention will be specifically described below based on Examples and Comparative Examples, but the present invention is not limited thereto. The properties were measured in the examples and comparative examples by the following methods.

(Sample) Polyolefin Resin Ethylene and 1-butene were mixed with a catalyst composed of triethylaluminum and a solid catalyst obtained from substantially anhydrous magnesium chloride, 1,2-dichloroethane and titanium tetrachloride. It was polymerized to obtain an ethylene / 1-butene copolymer. The catalyst component remained in an amount of Mg of 20 ppm.

This ethylene / α-olefin copolymer has a 1-butene content of 4 mol% and a density of 0.922 g / cm 3.
³ , MFR 2g / 10min.

(Initial Hue) After blending various additives with the polyolefin resin, a press sheet having a thickness of 2 mm was prepared, and its yellowness (according to JIS K7103) was measured to obtain the initial hue.

(Color stability) With a composition containing a phenolic antioxidant, it is a practical problem that the pellets or molded articles turn yellow after long-term storage. In the example in which a phenolic antioxidant was used in combination, an accelerated test was conducted to estimate the degree of yellowing during long-term storage. That is,
A 2 mm-thick press sheet made of the prepared composition was exposed to a thermo-hygrostat having a temperature of 80 ° C. and a relative humidity of 90% for 2 weeks, and then the yellow discoloration (according to JIS K7103) was measured.

(Thermal Stability) As a measure of the thermal stability when the composition was melt-kneaded, a change corresponding to a change in viscosity during kneading was measured. That is, the prepared composition was processed at 210 ° C. for 40 r using a Labo Plastomill manufactured by Toyo Seiki Co., Ltd.
After kneading at pm, the time (minutes) until the steady torque value shows a rapid rise change is measured for polyethylene, and the decrease rate (%) of the torque value after kneading for polypropylene is measured for 20 minutes. did. This is the degree of thermal deterioration. Further, a sample having a thickness of 0.2 mm was prepared from the adjusted composition by hot pressing, and a sample having a thickness of 200 mm was prepared using a differential calorimeter.
The oxygen induction period (OIT) under an oxygen stream at 0 ° C. was measured.

(Corrosion resistance) A phosphorus compound was placed in a petri dish, and a Gem clip was left on the powder, at a temperature of 30.
The sample was exposed to a thermo-hygrostat at a temperature of 90 ° C. and a relative humidity of 90%, and the time until rust was generated was measured.

[0041]

Examples 1 to 10 and Comparative Examples 1 to 14 Exemplified Compound 3 is selected as the phosphorus compound of the general formula (I) which is the component (a), and Exemplified compound 9 is selected as the compound of the general formula (II), and various additives are added. Was compounded. In Comparative Examples 1 and 2, other phosphorus compounds, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite and tetrakis (2,4-di-tert-butylphenyl) 4,4 '. An example of adding calcium stearate to biphenylene diphosphite is shown. Comparative Examples 3 and 4 show examples in which calcium stearate was added to Exemplified Compounds 3 and 9.

In Examples 1 and 2, these phosphorus compounds were used as component (b), Example 3 was used as component (c), calcium stearate and component (b), and Example 4 was used as component (c).
Calcium hydroxystearate and (b) as ingredients
In Example 5, an example in which a mixture of calcium stearate and stearic acid as the component (C) and the component (b) were blended was shown in Example 5. Compared to the comparative example, the oxidation resistance of each of the examples was significantly improved, and no rust was generated. Also, the initial hue is not yellowish.

In Comparative Example 5, tetrakis- [methylene-3- (3 ', 5'-di-] was used as a phenolic antioxidant.
An example was shown in which tert-butyl-4'-hydroxyphenyl) propionate] methane and calcium stearate were added. In Examples 6 and 7, the phosphorus compounds (c)
Calcium stearate and the component (b) are added as ingredients, and tetrakis- is added as a phenolic antioxidant.
[Methylene-3- (3 ', 5'-di-tert-butyl-4'
-Hydroxyphenyl) propionate] methane was added, Examples 8 and 9 include dilauryl-3,3'-thiodipropionate as a thioether antioxidant, and Examples 10 and 11 include Tetrakis- [methylene-3- as a phenolic antioxidant
(3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] methane, an example was shown in which dilauryl-3,3'-thiodipropionate was added as a thioether antioxidant. In Comparative Example 5, the hue during long-term storage is estimated to be poor, but in Examples 6 to 11, both the antioxidant performance and the hue are significantly improved.

[0044]

[Effect] By using the above-mentioned phosphorus-based material or hydrotalcite as a polyolefin, a polyolefin resin composition having excellent heat resistance and corrosion resistance and not yellowing can be obtained.

[0045]

[Table 1]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C08K 5/5398

Claims (5)

[Claims] 1. A polyolefin resin obtained by adding (A) one or more phosphorus compounds represented by the following general formula (I) or (II) to a polyolefin resin and (B) hydrotalcites. Composition. General formula (I): [In formula, R < ₁ >, R < ₂ > and R < ₃ > respectively show the same or different hydrogen, a hydrocarbon group, or an oxygen-containing hydrocarbon group.
Provided that at least one of R ₁ , R ₂ and R ₃ is _{- (C P H 2P O)} q -Z 3 or _-Z 4 _-OC r H,
_{2r + 1} is required (wherein Z ₃ represents a group having hydrogen or alkyl, cycloalkyl or aryl, and Z ₄ represents a group having arylene. P represents 2 to 2).
An integer of 9 and r is an integer of 1 to 10. ). ] General formula (II): [In the formula, R ₄ and R ₅ represent the same or different hydrocarbon groups or oxygen-containing hydrocarbon groups, respectively. n is an integer of 0-3. ] 2. The polyolefin resin composition according to claim 1, further comprising (C) one or more compounds selected from the group consisting of fatty acid metal salts, hydroxy fatty acid metal salts and fatty acids. 3. The polyolefin resin composition according to claim 1, further comprising (D) a hindered phenol-based antioxidant and / or a thioether-based antioxidant. 4. The polyolefin resin composition according to claim 1, wherein the polyolefin resin is polymerized using a highly active Ziegler resin and has not undergone a deashing step. 5. The hydrocarbon group represented by R ₁ , R ₂ and R _{3 in} the general formula (I) represents a group having any of alkyl, cycloalkyl, aryl or alkenyl, and oxygen of the oxygen-containing hydrocarbon group is The polyolefin resin composition according to any one of claims 1 to 4, which is oxygen of a hydroxyl group, an ether group or an epoxy group.