JPH03243641A - Thermally stabilized polyolefin resin composition - Google Patents

Abstract

PURPOSE:To obtain a polyolefin resin composition having extremely excellent heat stability, comprising a hindered phenol-based heat stabilizer, hindered amine-based weather resistance imparter and a small amount of organic hypophosphorous acid compound. CONSTITUTION:100 pts.wt. polyolefin resin is blended with (A) 0.01-10 pts.wt., preferably 0.05-1 pt.wt. hindered phenol-based heat stabilizer, (B) 0.01-10 pts.wt., preferably 0.05-1 pt.wt. hindered amine-based weather resistance imparter and (C) an organic hypophosphorous acid compound shown by formula I [X is >=1C organic cation; a and b are natural number and aXc=b (c is valence of X), preferably a compound shown by formula II (R1 is 1-22C alkyl or benzyl]; R2 to R4 are H, 1-22C alkylor benzyl), formula III (R1 to R6 are H, 1-22C alkyl or benzyl) or formula IV (R1 to R4 are 1-22C alkyl, phenylor benzyl) in a ratio of 0.05>C/B>=0.001.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a polyolefin resin composition with excellent thermal stability. Specifically, the present invention relates to a polyolefin resin composition with excellent thermal stability, which contains a hindered phenol heat stabilizer, a hindered amine weather resistance imparting agent, and an organic hypophosphorous acid compound.

<Prior Art> The amount of polyolefin resins used outdoors is increasing year by year. These polyolefin resins are required to have weather resistance depending on the purpose of use, and many weather resistance imparting agents have been developed so far. Recently, a hindered amine weathering agent called HALS (abbreviation for Hindered Real Light Stabilizer) has been developed to improve the weatherability of polyolefin resin compositions containing it, reducing the decrease in mechanical properties and changes in gloss and color when exposed outdoors. It is often used because it can provide a marked improvement over the case of agents (for example, JP-A-59-86645).

Further, since the processing stability and thermal stability of these polyolefin resins cannot be imparted by weather resistance imparting agents, a hindered phenol type thermal stabilizer is usually added as a thermal stabilizer.

<Problem to be solved by the invention> However, the hindered phenol heat stabilizer undergoes an inhibiting reaction by the hindered amine weatherability imparting agent in its heat stabilizing action mechanism, so that polyolefin resin compositions using both together cannot be used. It is difficult to obtain sufficient thermal stability,
It is prone to deterioration due to poor thermal stability such as gelation during processing, burning, and discoloration immediately after processing. In addition, it is known that discoloration of hindered phenol-based heat stabilizers is accelerated by hindered amine-based weatherability imparting agents, and hindered phenol-based heat stabilizers are used to improve the thermal stability of polyolefin resin compositions. If an increased amount is added, the discoloration of the product (discoloration originating from the hindered phenol heat stabilizer) will become significant, and the product value will be greatly reduced. It is an object of the present invention to provide a polyolefin resin composition containing a weather resistance imparting agent and having significantly improved thermal stability.

<Means for solving yl, s> The present inventors have proposed a polyolefin resin composition, particularly a heat-stable and weather-resistant polyolefin resin composition containing a hindered phenol heat stabilizer and a hindered amine weatherability imparting agent. I have continued my research. As a result, it was found that when a very small amount of organic hypophosphorous acid compound was added to a polyolefin resin composition containing a hindered phenol heat stabilizer and a hindered amine weatherability imparting agent, the thermal stability was significantly improved. However, the present invention was completed.

That is, the present invention provides a polyolefin resin with a hindered phenol heat stabilizer (I), a hindered amine weatherability imparting agent (II), and a hypophosphorous acid compound represented by the following general formula (I [I)]. , 05> (III)
/ (II)≧0.001.

X, (H!POZ), (III) The hindered phenol heat stabilizer (1) used in the present invention is represented by the following formula (1).

Specifically, 2,6-dialkylphenol derivatives,
Examples include 2-alkylphenol derivatives, including the following (1)
The compounds shown in ~(8) can be exemplified.

○H Hindered amine resistance imparting agent (I) used in the present invention
I) is represented by the following formula.

Part 4 As a substituent at position, for example, carbon Acid 9! Based on Examples include alkoxy groups and other various groups.

Furthermore, the N-position may be substituted with an alkyl group, etc. Specifically, the following (9)-(16) formula The following compounds can be exemplified.

(13) (14) The organic hypophosphorous acid compound ([[) used in the present invention is
The following general formula (l[[-a), (1-b) or (m-c
) is a hypophosphite having an organic cation represented by

1 Specific examples include tetrabutylammonium hypophosphite, cetyltrimethylammonium hypophosphite, tetraphenylphosphonium hypophosphite, tetrabutylphosphonium hypophosphite, hypophosphorous #N-cetylpyridinium, hypophosphite Examples include benzyltriethylammonium phosphate.

Polyolefin resins used in the present invention include polyethylene, polypropylene, poly-1-butene, poly-
Homopolymers of olefins such as 4-methyl-1-pentene, ethylene-propylene-propylene copolymer, ethylene-
Propylene random copolymer, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-
Olefin copolymers such as 4-methyl-1-pentene copolymer, ethylene-1-octene copolymer, propylene-1-butene copolymer, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, etc. Examples include polymers, copolymers of olefins such as ionomer resins, and polar vinyl compounds.

The blending ratio of each component of the polyolefin resin composition of the present invention is, for example, as follows.

Hindered phenol heat stabilizer is resin 100! It is used in a range of 0.01 to 10 parts by weight, preferably 0.05 to 1 part by weight. If it is less than 0.01 part by weight, the effect of improving thermal stability is poor, and even if it is added in excess of 10 parts by weight, no further significant improvement in thermal stability is observed, which is uneconomical. Hindered tunol type heat stabilizers are not preferred because they may bleed or discolor.

The hindered amine type weather resistance imparting agent is generally used in an amount of 0.01 to 10 parts by weight, preferably 0.05 to 1 part by weight, per 100 parts by weight of the resin. If it is less than 0.01 parts by weight, the effect of imparting weather resistance is poor, and even if it exceeds 10 parts by weight, no further significant improvement in the effect of imparting weather resistance can be seen, which is uneconomical. This is not preferable because the imparting agent may bleed and discolor.

The blending ratio of the organic hypophosphorous acid compound is usually 1 part by weight or more of 0OO and less than 0.05 part by weight per 1 part by weight of the hindered amine weatherability imparting agent. If the amount is less than 0.001 part by weight, the effect of improving thermal stability will be poor, and if it is more than 0.05 part by weight, the organic hypophosphorous acid compound will bleed.
Polyolefin resin &gThere is a possibility of damaging the appearance of the item.

The polyolefin resin composition of the present invention may contain other heat stabilizers, such as sulfur compounds having a thiol bond or thioether bond containing a divalent sulfur atom, or a trivalent phosphorus atom, to the extent that the object of the present invention is not impaired. It can contain a compound having a phosphite bond, an ultraviolet absorber, an antifogging agent, an antistatic agent, a lubricant, a filler, a flame retardant, a pigment, etc. as components.

The method of blending the above-mentioned components is not particularly limited, and they can be blended by a common method such as a Banbury mixer, a mixing roll, or an extruder.

<Effects of the Invention> According to the present invention, thermal stability can be improved by adding a small amount of an organic hypophosphorous acid compound to a polyolefin resin composition containing a hindered phenol heat stabilizer and a hindered amine weatherability imparting agent. It is possible to obtain a resin composition with significantly improved properties.

As shown in the examples below, when a small amount of an organic hypophosphorous acid compound is added to a polyolefin resin composition containing a hindered phenol heat stabilizer and a hindered amine weatherability imparting agent, the heat resistance is greater than when the organic hypophosphorous acid compound is not added. Stability is significantly improved. Furthermore, discoloration during storage, which is often observed in resin compositions containing a hindered phenol heat stabilizer and a hindered amine weatherability imparting agent, is significantly improved.

The polyolefin resin & II material of the present invention can be formed into various shapes such as films, sheets, fibers, and molded products and used for various purposes such as agricultural films and automobile materials. In particular, when a polyolefin such as polyethylene, ethylene-1-butene copolymer, or ethylene-vinyl acetate copolymer is used as the polyolefin resin, the film obtained from the polyolefin resin composition of the present invention can be used as a packaging film or agricultural film. It is extremely useful as a covering material for houses, tunnels, etc. Furthermore, the polyolefin resin composition of the present invention is particularly useful for outdoor applications such as automobile materials such as bumpers and materials that require high weather resistance such as building materials such as garage roofs.

<Examples> Examples of the present invention will be shown below, but the present invention is not limited thereto.

The test methods in the examples are as follows.

Thermal stability test (1) 1 g of a 1 m thick test piece was heated at a tank temperature of 210°C in the dark using a polymer material deterioration measuring device manufactured by Shibayama Kagaku Kikai Seisakusho.
The oxygen absorption induction period was measured under the condition of an oxygen amount of 40 Id.

The oxygen absorption induction period was expressed as the time from when the temperature inside the tank became constant until the amount of oxygen in the system decreased by 0°9adfi or, in the case of decomposed gas, the volume of oxygen in the system reached its minimum value. The longer the oxygen absorption induction period, the better the oxidative deterioration resistance, that is, the thermal stability.

Thermal stability test (2) A test piece with a thickness of 1 cm cut into a size of 3C11 x 3CI was kept in an oven at 180"C for 13 hours under air, and the color change (ΔE) was observed before and after aging. was measured using an SM color computer [F] manufactured by Suga Test Co., Ltd.

The smaller the value of ΔE, the smaller the color change, indicating that the oxidative deterioration resistance, that is, the thermal stability is excellent.

Weather resistance test A test piece punched out with a JISI dumbbell was tested using an ICE-PAR UV tester (model SUM) manufactured by IFRAFIX ■.
-Wll modified product) with a light intensity of 100 leaks-/c-d
, the distance from the light source was 24 CI, the air temperature was 60° C., and the relative humidity was 33%.

The aged test piece was subjected to a tensile test using Autograph@DSS100 manufactured by Shimadzu Corporation to measure the elongation rate (%), and the elongation rate was half that of the original test piece. The weather resistance test time (hereinafter referred to as "weather resistance half-life") was determined. The larger the value of this time, the better the weather resistance.

Discoloration test 3 A test piece with a thickness of 1 m cut into a size of 3 cm x 3 cm was aged for 5 days in the air at 60°C and 90% relative humidity, and the change in yellowness before and after aging was observed. (Yellow index ΔYl) was measured using an SM color computer [F] manufactured by Suga Test Instruments ■.

The smaller the value of ΔYl, the smaller the change in color, indicating that the color fastness is excellent.

Furthermore, the organic hypophosphorous acid compound used in this example was produced according to the method exemplified below.

[Example of production of organic hypophosphorous acid compound]

After filling a glass column with an inner diameter of 4 c- with 100 g of ion exchange resin Amberlite IRA-40 (manufactured by Organo ■), a 2N hypophosphorous acid l-I) rum aqueous solution 185 (ld
It was confirmed that no sodium chloride or sodium hypophosphite was detected in the effluent from which 1000 ml of distilled water was sequentially poured. Next, cetyltrimethylammonium bromide 10
A solution prepared by dissolving 1.0 g in 40 d of distilled water was poured into the column, and 5.0 I11 of so-called distilled water was further passed through the column. The effluent was collected and dried under reduced pressure to obtain 9.1 g of cetyltrimethylammonium hypophosphite. (purity>95%, verified by infrared spectroscopy).

Examples 1 to 3 As shown in Table 1, a resin, an organic hypophosphorous acid compound, a heat stabilizer, and a weatherability imparting agent were mixed, kneaded in a Banbury mixer at 150°C for 15 minutes, and then granulated with an extruder. and got a beret. These pellets were molded into a sheet with a thickness of 1 by press molding and a film with a thickness of 50μ by inflation. ) and weather resistance tests were conducted.

Comparative Examples 1-2 Tests similar to Examples 1-3 were conducted using the formulations shown in Table 1. The results showed that both had poor thermal stability.

Examples 4-10 Resin, organic hypophosphorous acid compound, as shown in Table 2
A heat stabilizer and a weather resistance imparting agent were blended, and the mixture was kneaded for 5 minutes at 160°C and 160 rpm in a Toyo Seiki Labo Blast Mill, and then molded into a 1-thick sheet using the breath molding method and subjected to a thermal stability test ( 1) (tank temperature 210°C) was carried out. As shown in Table 2, the results showed excellent thermal stability.

Comparative Examples 3-5 Examples 4-6 except that no organic hypophosphorous acid compound was used
Thermal stability test (1) (
The temperature inside the tank was 210°C).

The results showed that both had poor thermal stability.

Examples 11 to 14 The resin, organic hypophosphorous acid compound, heat stabilizer, and weather resistance imparting agent as shown in Table 3 were blended and kneaded for 5 minutes at 160°C and 160 rpm using Labo Plastomill manufactured by Toyo Seiki Seisakusho. Thereafter, it was molded into a sheet with a thickness of 1-1 by a breath molding method, and a thermal stability test (1) was conducted (temperature inside the tank: 210'C).

As shown in Table 3, the results showed excellent thermal stability.

Comparative Examples 6-9 Examples 11-9 except that no organic hypophosphorous acid compound is used
Thermal stability test (1
) (tank salinity 210°C).

The results showed that both had poor thermal stability.

Example 15 Resin, heat stabilizer, weather resistance imparting agent as shown in Table 4,
Diglycerin sesquiolate and cetyltrimethylammonium hypophosphite were blended and kneaded for 5 minutes at 160°C at 160 rpm in a Laboplasto Mill manufactured by Toyo Seiki Seisakusho, and then molded into a sheet with a thickness of 11 mm using the breath molding method and heat stabilized. A property test (2) and a color change test were conducted.

As shown in Table 4, the results showed excellent thermal stability and color fastness.

Comparative Example 1O Thermal stability test (2) in the same manner as in Example 15 except that cetyltrimethylammonium hypophosphite was not used.
And a color change test was conducted.

As shown in Table 4, the results were poor in both thermal stability and color fastness.

Claims (2)

[Claims] (1) Polyolefin resin, hindered phenol heat stabilizer (I), hindered amine weatherability imparting agent (
II) and an organic hypophosphorous acid compound represented by the following general formula (III) in a ratio of 0.05>(III)/(II)≧0.001. X_a(H_2PO_2)_b(III) [X: organic cation having 1 or more carbon atoms. a and b are natural numbers. a×c=b (where c is the valence of X)] (2) The organic hypophosphorous acid compound (III) has the following general formula (
The polyolefin resin composition according to claim 1, which is represented by III-a), (III-b) or (III-c). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (III-a) [R_1 represents an alkyl group or benzyl group having 1 to 22 carbon atoms, and R_2 to R_4 represent hydrogen or a group having 1 to 22 carbon atoms.
22 shows an alkyl group and a benzyl group. ] ▲ Numerical formulas, chemical formulas, tables, etc. are included ▼ (III-b) [R_1 to R_6 represent hydrogen, an alkyl group having 1 to 22 carbon atoms, or a benzyl group. ] ▲ Numerical formulas, chemical formulas, tables, etc. are included ▼ (III-c) [R_1 to R_4 represent an alkyl group having 1 to 22 carbon atoms, a phenyl group, or a benzyl group. ]