JPH0525330A - Stabilization of polyolefin - Google Patents

Abstract

PURPOSE:To stabilize a polyolefin useful for beer crates and agricultural films etc., by imparting it with heat deterioration resistance and weatherability etc. through incorporating it with a combination of a piperidine derivative and phenolic antioxidant. CONSTITUTION:The stabilization can be accomplished by incorporating 100 pts.wt. of a polyolefin with (A) 0.05-1 pt.wt. of a compound of formula I (R and R<1> are each H or methyl; R<2> and R<4> are each 1-18C alkyl or of formula II; (n) and (m) are each 1-3) (e.g. a compound of formula III or IV), (B) 0.05-1 pt.wt. of a phenolic antioxidant such as 2.6-di-t-butyl-p-cresol and (C) other additive(s) such as light stabilizer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel stabilizing method which is incorporated into a polyolefin to suppress thermo-oxidative deterioration and deterioration of the resin due to light. This processed polyolefin product is useful as a beer crate, an agricultural film, an automobile exterior product, and a hollow container.

[0002]

2. Description of the Related Art Generally, synthetic resins such as polyethylene, polypropylene, polyvinyl chloride and ABS are deteriorated by heat during molding or oxidation, or deteriorated in weather resistance mainly due to ultraviolet rays and oxygen even after they are made into products. It is known that this causes a change in color, a decrease in mechanical strength, and the like and cannot withstand long-term use.

In order to eliminate such drawbacks, it is necessary to add one kind or several kinds of heat stabilizers or light stabilizers to the synthetic resin to suppress various deteriorations. Such heat stabilizers are generally tetrakis [methylene-3- (3,5
-Di-t-butyl-4-hydroxyphenyl) -propionate] methane (trade name, R manufactured by Ciba-Geigy Co., Ltd.)
A-1010) and other phenolic antioxidants are mainly used, and as the light stabilizer, bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate (a product name of Sankyo Co., Ltd., Sanol) is used. Hindered amine compounds such as LS770) are generally known.

[0004]

However, there is the disadvantage that there is an antagonistic action between certain heat stabilizers and light stabilizers. That is, for the purpose of improving both heat aging resistance and weather resistance of the synthetic resin, for example, RA-10 as a heat stabilizer.
10. It is known that when Sanol LS770 as a light stabilizer is added to a synthetic resin in combination, the heat aging resistance is significantly reduced as compared with the case where each compound is added alone.

[0005]

Means for Solving the Problems In view of the present situation, the present inventor has conducted extensive studies, and as a result, when blending various phenolic antioxidants for the purpose of improving the heat aging resistance of polyolefin, the following general formula It was found that by adding together the piperazine derivative represented by (I), a polymer material having not only heat aging resistance but also weather resistance can be obtained significantly.

That is, the present invention provides a method for stabilizing a polyolefin, characterized in that the piperidine derivative represented by the following general formula (I) is used in combination with a phenolic antioxidant.

[0007]

[Chemical 3]

[In the formula, R and R'represent a hydrogen atom or a methyl group, and R ² and R ⁴ are an alkyl group having 1 to 18 carbon atoms or

[0009]

[Chemical 4]

A group is shown. n and m are numbers 1 to 3. ]
A rational formula of a typical compound as the stabilizer represented by the formula (I) is shown below.

[0011]

[Chemical 5]

[0012]

[Chemical 6]

The amount of the piperazine derivative represented by the general formula (I) used in the present invention is 1
It is usually used in a proportion of 0.05 to 1 part by weight, preferably 0.08 to 0.5 part by weight, relative to 00 parts by weight.

The stabilizing method of the present invention comprises the above-mentioned general formula (I).
By using the piperazine derivative represented by the formula (1) in combination with a phenolic antioxidant, a processed polyolefin product having excellent thermal stability and weather resistance can be produced.

As such a phenolic antioxidant,
For example, 2,6-di-t-butyl-p-cresol, stearyl- (3,6-di-t-methyl-4-hydroxybenzyl) thioglycolate, stearyl-β- (4-
Hydroxy-3,5-di-t-butylphenyl), propionate, distearyl (4-hydroxy-3-methyl-5-t-butyl) benzyl malonate, 2,2'-
Methylenebis (4-methyl-6-t-butylphenol), 4,4'-methylenebis (2,6-di-t-butylphenol), 2,2'-methylenebis [6- (1-
Methylcyclohexyl) p-cresol], bis [3,3
3-bis (4-hydroxy-3-t-butylphenyl)
Butyric acid) glycol ester, 4,4′-butylidene bis (6-t-butyl-m-cresol),
1,1,3-tris (2-methyl-4-hydroxy-5)
-T-butylphenyl) butane, 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl)
-2,4,6-trimethylbenzene, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, 1,3,5-tris (3,5-di-) t-Butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris [(3,5
-Di-t-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate, 2-octylthio-4,6-di (4-hydroxy-3,5-di-t-butyl) phenoxy-1,3,5 -Triazine, 4,4 '
-Thiobis (6-t-butyl-m-cresol) and the like.

Further, in the method of the present invention, a sulfur type antioxidant can be used in combination. Such antioxidants include distearyl thiodipropionate, dilauryl thiodipropionate, pentaerythritol tetra (β
-Lauryl thiopropionate), 1,3,5-tris-β-latelyl thiopropionyloxyethyl isocyanurate and the like. These stabilizers are used in a proportion of 0.05 to 1 part by weight with respect to 100 parts by weight of polyolefin.

In the resin composition containing the stabilizer of the present invention,
Furthermore, heat resistance and weather resistance can be further improved by adding a phosphite compound. Such compounds include trioctyl phosphite, trilauryl phosphite, triphenyl phosphite,
Examples thereof include phosphite compounds such as tris (nonylphenyl) phosphite and distearyl pentaerythritol diphosphite.

In addition, weather resistance can be improved by further adding a light stabilizer (ultraviolet absorber) depending on the use. These include benzophenone-based, benzotriazole-based, succinate-based, substituted acrylonitrile-based,
Compounds such as nickel complex salts are included. This is used in a proportion of 0.05 to 5 parts by weight, preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the synthetic resin.

In addition, if necessary, for example, pigment, filler, foaming agent, antistatic agent, antifogging agent, surface treatment agent, lubricant, flame retardant, metal deactivator, nucleating agent, metal soap, transparent. Agents, processing aids, antifungal agents, bactericides, release agents and the like can also be included.

Examples of the polyolefin to which the stabilizer of the present invention is added include low density polyethylene, medium density polyethylene, linear-low density polyethylene, polypropylene,
Poly α-olefins such as polybutene-1, ethylene-
Propylene random or block copolymers, poly-α-olefin copolymers such as ethylene-butene-1 random copolymers, copolymers of poly-α-olefins and vinyl monomers such as maleic anhydride modified polypropylene, and mixtures thereof. Can be mentioned.

[0021]

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

Synthesis Example 1 (Exemplary Compound No. 1) Myristyl acrylate 10.0 was placed in a four-necked flask.
g, 1.61 g of piperazine and 60 ml of ethanol were added, and the mixture was stirred in a nitrogen stream and heating was started. After continuing heating at a temperature of 60 ° C. for 5 hours and then cooling to room temperature, white crystals were precipitated.

The crystals were separated by filtration and recrystallized with ethanol to obtain 10.6 g of the desired product (yield 91%).

(Analysis value) H ¹ -NMR absorption spectrum [CDCl ₃ , δ (ppm)] 0.70 to 1.76 (5
4H, m), 2.26 to 2.87 (16H, m), 4.
05 (4H, t) IR absorption spectrum [KBr wave number (Cm ⁻¹ )] 2910, 1730, 1325, 1310, 1185,
1155, 720.

MS [m / e, accurate mass spectrometry] 622, 6 (M ⁺ ) Synthesis Example 2 (Exemplified Compound No. 2) Myristyl crotonic acid 10.0 was placed in a four-necked flask.
g, 1.53 g of piperazine and 60 ml of ethanol were added, and the mixture was stirred in a nitrogen stream and heating was started. After continuing heating at a temperature of 60 ° C. for 10 hours and then cooling to room temperature, white crystals were precipitated.

The crystals were separated by filtration and recrystallized from ethanol to obtain 2.7 g of the desired product (yield 23.4%).

(Analysis value) H ¹ -NMR absorption spectrum [CDCl ₃ , δ (ppm)] 0.66 to 1.83 (6
0H, m), 2.07 to 2.75 (12H, m), 2.
90-3.33 (2H, m), 4.03 (4H, t).

IR absorption spectrum [KBr wave number (Cm
^-1 )] 2940, 1735, 1330, 1195, 1155.

MS [m / e, (relative intensity)] 650 (43, M ⁺ ), 394 (62), 326 (4
3), 113 (100), 87 (41) Synthesis Example 3 (Exemplified Compound No. 7) 2,2,6,6-tetramethyl-in a four-necked flask.
4-Acryloyloxy-piperidine (15.0 g), piperazine (3.0 g) and ethanol (60 ml) were added, and the mixture was stirred in a nitrogen stream and heating was started. After continuing heating at a temperature of 60 ° C. for 5 hours, the mixture was cooled to room temperature and ethanol was distilled off under reduced pressure to obtain white crystals.

This crystal was recrystallized from acetone,
16.4 g of the desired product was obtained (yield 93%).

(Analytical value) H ¹ -NMR absorption spectrum [CDCl ₃ , δ (ppm)] 0.65 to 1.40 (3
0H, m), 1.93 (4H, dd), 2.26-2.
90 (16H, m), 4.92 to 5.55 (2H, m) IR absorption spectrum [KBr wave number (Cm ^-1 )] 3310, 2975, 1720, 1345, 1300,
1235, 1175, 750 MS [m / e, (relative intensity)] 508 (1, M ⁺ ), 140 (33), 124 (10
0), 58 (27) Next, the stabilizing effect by the method of the present invention will be illustrated by Examples and Comparative Examples.

Examples 1 to 7, Comparative Examples 1 to 4 Polypropylene powder 1 having an intrinsic viscosity of 1.9 measured in 135 ° C. tetralin and 98% isotactic polypropylene powder 1
Each additive shown in Table 1 was added to 00 parts by weight and mixed well with a mixer.

Cylinder temperature 260 ° C., L / D =
This mixture was melt-kneaded and granulated by an extruder having a diameter of 20,20 mm. The pellets thus obtained were compression molded at 230 ° C. into a sheet having a thickness of 0.5 mm to obtain a test piece.

The heat aging resistance was measured by measuring the time required for heating the test piece in a circulating air oven at 150 ° C. until the test piece became brown and embrittled by oxidative deterioration.

The weather resistance is 65 / XW-WR type xenon weather ometer manufactured by Atlas Co., Ltd. When the test piece is irradiated with light at a black panel temperature of 80 ° C. and bent at 180 ° C., the test piece becomes brittle. The time required to generate a crack was measured.

The results are shown in Table 1.

The abbreviations in the table are as follows.

* 1 Tetrakis [3- (3,5-di-t
-Butyl-4-hydroxyphenyl) propionyloxymethyl] methane * 2 Trade name Sanol LS770 (trade name) manufactured by Sankyo Co., Ltd. * 3 Trade name Tinuvin 326 (trade name) manufactured by ADEKA ARGUS * 4 Trade name Mark PEP-8 (Made by ADEKA ARGUS)

[0039]

[Table 1]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masami Takahashi 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Petrochemical Co., Ltd.

Claims (1)

What is claimed is: (1) General formula: [Wherein R and R'represent a hydrogen atom or a methyl group,
R ² and R ⁴ are alkyl groups having 1 to 18 carbon atoms or Indicates a group. n and m are numbers 1 to 3. ] The stabilization method of the polyolefin characterized by using together the piperidine derivative represented by these, and a phenolic antioxidant.