JPS636039A - Polyethylene resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin compsn. having improved resistance to tear, impact and blocking and properties with respect to deterioration by heat, by blending a specified linear low-density polyethylene with a specified phosphorus compd., a phenolic antioxidant and an amorphous anhydrous aminosilicate. CONSTITUTION:A resin compsn. is obtd. by blending 100pts.wt. linear low-density polyethylene (A) composed of 90-99mol% of ethylene unit, 0.4-9.5mol% of a 3-4C alpha-olefin unit and 0.4-9.5mol% of a 6-12C alpha-olefin unit with 0.01-1.0pt.wt. at least one phosphorus compd. (B) selected from the group consisting of phosphites, phosphonites and phosphonic acid derivatives, 0.01-1.0pt.wt. phenolic antioxidant (C) having an MW of not lower than 400 and 0.01-2.0pts.wt. amorphous anhydrous aminosilicate (D) having the fundamental particle form of zeolite, obtd. by treating zeolite with an acid.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polyethylene resin composition, and more particularly to an ethylene resin composition.

[Conventional technology 2 Problems to be solved by the invention] Linear low-density polyethylene has excellent mechanical properties.

Due to its transparency and heat sealability, it is expected to be used as packaging materials, agricultural films, etc.

However, this linear low-density polyethylene has the problem of yellowing and thermal deterioration during high-temperature processing such as extrusion molding, injection molding, and blow molding.

In order to solve this problem, it has been proposed to incorporate a phosphorus compound into the polyethylene, but a sufficiently satisfactory effect has not yet been obtained.

c. Means for Solving the Problems] As a result of various studies in order to solve the above problems, the present inventors used a specific linear low-density polyethylene as the polyethylene, and added a specific phosphorus compound to the polyethylene. It was discovered that a product with a high commercial value, which is a phenolic antioxidant and has improved anhydrous locking properties, can be obtained, and based on this knowledge, the present invention was completed.

That is, the present invention comprises (A) 90 to 99 mol% of ethylene units and 0.4 to 9.5 α-olefin units having 3 to 4 carbon atoms;
Mol% and α-olefin units having 6 to 12 carbon atoms: 0.
Linear low density polyethylene consisting of 4 to 9.5 mol% (
Hereinafter, it will be referred to as LLDPE. ) 100 parts by weight, (
B) 0.01 to 1.0 parts by weight of at least one phosphorus compound selected from the group consisting of phosphites, phosphonites, and phosphonic acid derivatives; (C) 0.01 parts by weight of a phenolic antioxidant having a molecular weight of 400 or more; 1.0 parts by weight and (D) 0.01 to 2.0 parts by weight (anhydrous amorphous aluminosilicate obtained by acid treatment of zeolite and having the basic particle morphology of zeolite). The present invention relates to a polyethylene resin composition characterized by:

The polyethylene used as component (A) in the present invention is as described above (LLDPE, with 90 to 9 ethylene units).
9 mol% contains 3 to 4 carbon atoms such as propylene, butene-1, etc.
0.4 to 9.5 mol% of α-olefin units, preferably 0.5 to . 5 mol% and 0.4 to 9.5 α-olefin units having 6 to 12 carbon atoms such as hexene-1,3-methyl-pentene-1,4-methyl-pentene-1, octene-1, decene-1, etc. It is obtained by blending in a proportion of mol %, preferably 0.5 to 5 mol %, and copolymerizing in liquid phase or gas phase. Preferred examples of LLDPE include a combination of ethylene-propylene-octene-1 and a combination of ethylene-butene-octene-1, with the latter being particularly suitable. Such LLDPE has a melt flow ratio (
MFR=flow rate/melting index, where the flow rate is ASTM D-
1238 Condition E: 10 of the weight used in the melting index test below
Measured in multiples. ) is 18 to 52, especially 23 to 48, and the density (according to JIS K7110. density gradient tube method) is 0.
．． 910-0.940 g/ci, preferably 0.91
0 to 0.936, and the melting index (MI, ASTM
D-1238 Condition E: Measured at 190°C) is 0.1 to 10
g/10 minutes, preferably 0.5 to 5 g/10 minutes.

Here, when the MFR is less than 17, the molding processability of the resin composition deteriorates, and when it exceeds 52, the transparency deteriorates.

When the MFR is from 23 to 48, the resulting resin composition will have good impact resistance.

LLDPE as described above can be manufactured by applying known methods. For example, it can be produced by supplying α-olefins to a polymerization system so that the content of each α-olefin unit becomes a predetermined value, and performing random copolymerization in a liquid phase or a gas phase. In this case, the supply ratio of α-olefin is appropriately adjusted depending on the type of α-olefin, the degree of polymerization, the partial pressure of ethylene, etc.

Next, the phosphorus compound used as component (B) in the present invention is at least one selected from phosphites, phosphonites, and phosphonic acid derivatives.

Here, various phosphites are mentioned, such as triphenyl phosphite; diphenyl phosphite; didecyl phenyl phosphite; tridecyl phosphite; trioctyl phosphite; tridodecyl phosphite; triotadecyl phosphite; nylphenyl phosphite; tridodecyl trithiophosphite; distearyl pentaerythritol diphosphite), 4,4'-butylidene bis(3-methyl-6-t-
butylphenylditridecyl) phosphite; tris(
2,4-di-t-butylphenyl) phosphite; bis(
In addition to 2,4di(monobutylphenyl)pentaerythritol diphosphite, 4°4'-isopropylidene diphenyl tetraalkyl diphosphite having an alkyl group having 12 to 15 carbon atoms can be mentioned.

In addition, as a phosphonite, for example, tetrakis (2,4
-dialkylphenyl)-4,4'-biphenylene diphosphonite. Note that the alkyl group here has 1 to 30 carbon atoms. Among these, especially tetrakis (2,4-di-t-butylphenyl)
-4,4'-biphenylene diphosphonite is preferred.

Furthermore, the phosphonic acid derivative is represented by the general formula. In the formula, R1 represents hydrogen, a metal, or a linear or branched alkyl group having 1 to 22 carbon atoms, and R2 represents a lower alkyl group having 1 to 6 carbon atoms, preferably a tert-butyl group. Specifically, for example,
4-hydroxy-3゜5-di-t-butylbenzylphosphonic acid; 〇-ethyl-(4-hydroxy-3,5-di(-butylbenzyl)phosphonic acid; o-(2-ethylhexyl)-(4-hydroxy) -3,5-zyl-t-butylbenzyl)phosphonic acid; 0-ethyl-(4-hydroxy-3,5-di-t-butylbenzyl)phosphonic acid; 0-
Examples include calcium salt of ethyl-(4-hydroxy-3°5-t-butylbenzyl)phosphonic acid.

The phosphorus compound as component (B) is blended in a proportion of 0.01 to 1.0 parts by weight per 100 parts by weight of component (8). If the blending ratio of the phosphorus compound is less than 0.01 parts by weight, the molecular weight of the resulting composition decreases, and yellowing during high-temperature processing cannot be sufficiently prevented. - On the other hand, even if the phosphorus compound is blended in an amount exceeding 1.0 parts by weight,
This is not preferable because it does not improve the effect on molecular weight reduction or yellowing, and conversely causes deterioration in quality such as bleed-out when added in a large amount.

Component (C) in the present invention is a phenolic antioxidant, and has a molecular weight of 400 or more, preferably 4QO to 50.
00. If a phenolic antioxidant with a molecular weight of less than 400 is blended here, the yellowness during high-temperature processing will increase, causing a decrease in quality, which is not preferable. There are various phenolic antioxidants with a molecular weight of 400 or more, such as octadecyl 3-(
3,5-di-t-butyl-4-hydroxyphenyl)propionate; pentaerythrityl-tetrakis(3-
(3,5-di-t-butyl-4-hydroxyphenyl)
propionate); 1,3.5-)dimethyl-2,4
,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene; 1°3.5-)lis-[ethylene-3-(3,5-di-t-butyl-4-hydroxy phenyl)propionate”J-s-triazine-2,4
,6-(LH.

3H,5H) l-ion; 1,1.3-)lis(2-methyl-4-hydroxy-5-t-butylphenolbutane; 4,4'-methylene-bis(2,6-di-t-butylphenol) ;Hexamethylene glycol-bis[β
-(3,5-di-t-butyl-4-hydroxyphenol)propionate]; 6-(4-hydroxy-3,5
-di-t-butylanilino)-2,4- and suoctyl-thio-1°3.5-)lyazole; 2,2'-thio[diethyl-bis-3(3,5-di-C-butyl- 4
-hydroxyphenol)propionate]i2,2'
-methylene-bis(4-methyl-6-t-nonylphenol); 2,6-bis=(2'-hydroxy-3'-t
-butyl-5-methylbenzoyl)-4-methylphenol; tris[β-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl-oxyethyl]isocyanurate, etc.; It can be used alone or in combination.

The blending ratio of the phenolic antioxidant is 0.01 to 1.0 parts by weight per 100 parts by weight of component (A).

Here, the blending ratio of the phenolic antioxidant is 0.01
If the amount is less than 1 part by weight, the molecular weight of the resulting composition decreases, and yellowing during high-temperature processing cannot be sufficiently prevented. - On the other hand, even if the phenolic antioxidant is blended in an amount exceeding 1.0 parts by weight, the effect on molecular weight reduction and yellowing will not be improved, and on the contrary, blending in a large amount will cause quality deterioration such as bleed-out. So I don't like it.

Next, in the present invention, anhydrous amorphous aluminosilicate, which is obtained by acid treatment of zeolite and has the basic particle form of zeolite, is used as component (D). Although this material has the basic particle shape and particle size distribution of zeolite, it is anhydrous and amorphous and does not have a crystalline structure like zeolite. Here, amorphous does not only mean that no diffraction lines are observed in the X-ray diffraction diagram, but also that the height of the diffraction lines is reduced to less than half that of zeolite, making it substantially amorphous. It refers to things including things that exist.

Component (D) in the present invention is the above-mentioned anhydrous amorphous aluminosilicate, but this product is not only made anhydrous by heating and dehydrating in advance, but also by heating during kneading with other components. It may be dehydrated by treatment to become anhydrous.

The anhydrous amorphous aluminosilicate as component (D) preferably has an average particle diameter of 0.5 to 5 μm, particularly 1.5 to 3.5 μm, and more preferably 1/2 to 3/2 of the average particle diameter. It is preferable that the particle size distribution of particles within this range accounts for 50% or more of the total. The particle shape of component (D) is preferably spherical or cubic with rounded edges, and the particle surface is smooth.

Such anhydrous amorphous aluminosilicate can be produced by various methods, one example of which is shown below.

First of all, the raw material zeolite may be natural or synthetic, but SiO□/Al
It is preferable to use one having a tos (molar ratio) of 5 or less, particularly 4 or less. This is because its unique crystal structure is easily decomposed by the acid treatment described below. Specific examples of such zeolites include A-type zeolite, P-type zeolite, X-type zeolite, Y-type zeolite, etc., and these can be used alone or in combination of two or more types. In the present invention, among these, it is particularly preferable to use type A zeolite and type X zeolite, which are nearly spherical.

Next, such zeolite is acid-treated. This acid treatment results in a zeolite that is substantially amorphous while retaining the basic particle morphology of the zeolite.

Here, the acid treatment is performed by adding an acid or an acidic substance such as sulfuric acid or phosphoric acid to the aqueous slurry of zeolite. This acid treatment increases the p of the aqueous zeolite slurry.
The H value is adjusted to a weak acidity of 4.5 to 9, preferably 5 to 7. If the pH of the aqueous slurry is less than 4.5, the basic particle morphology such as the particle shape and particle size distribution of the zeolite may change significantly, or the entire particle may dissolve or disappear, so it is preferable. In addition, if the pH of the aqueous slurry exceeds 9, it is not preferable because it is difficult to become amorphous.

The thus obtained amorphous aluminosilicate having the basic particle form of zeolite is heated and dehydrated to form anhydrous amorphous aluminosilicate. Here, the heating dehydration treatment was performed to convert the above amorphous aluminosilicate into
This is carried out by heating to a temperature of 0.degree. C. or higher, preferably 250 to 500.degree.

Since the component (D) obtained on the ridges has been acid-treated, it does not adsorb water unlike ordinary heat-dehydrated zeolite. Therefore, the adverse effects of water in the molding process can be substantially prevented. Moreover, this component (D) does not substantially impair the transparency of polyethylene. Note that this component (D) is usually of the Na type, and although the cation exchange ability characteristic of zeolite has virtually disappeared, the slight remaining cation exchange ability allows Na'' to be exchanged with other It is also possible to substitute cations such as Ca", Mg", Ba", Zn", Pb", etc. In addition, aluminum, titanium,
Coating treatment with metal hydroxides such as zirconium and antimony, amorphous silica, etc. can also be performed.

In the present invention, this (D) component is the above-mentioned (A) component 1.
0.01 to 2.0 parts by weight, preferably 0.05 to 1.5 parts by weight. here(
If the addition ratio of component D) is less than 0.01 part by weight, blocking resistance cannot be improved. - way, (
If the addition ratio of component D) exceeds 2.0 parts by weight, transparency decreases, which is not preferable.

The polyethylene resin composition of the present invention consists of the above four components, and if necessary, other additives such as metal oxides such as calcium stearate and zinc stearate; antistatic agents; weathering agents; blowing agents; and pigments. may be blended.

The polyethylene resin composition of the present invention can be obtained by blending predetermined amounts of each of the above-mentioned components and thoroughly kneading the mixture by a dry-wet/melt-mixing method, a multistage melt-mixing method, a simple melt-mixing method, or the like. The kneading can be carried out using a Banbury mixer, a co-kneader, an extruder, a twin-screw kneader, or the like.

The polyethylene resin composition of the present invention thus obtained is molded into a suitable shape by various molding methods such as extrusion molding, injection molding, and blow molding to produce a product.

〔Effect of the invention〕

According to the polyethylene resin composition of the present invention, extrusion molding,
Yellowing during high-temperature processing such as injection molding and blow molding can be sufficiently prevented, and there is no risk of problems such as reduction in commercial value. Moreover, according to the polyethylene resin composition of the present invention, thermal deterioration during high-temperature processing can be sufficiently prevented, and there is no fear that the viscosity or the like will change significantly even if high-temperature processing is repeated. Therefore, stable molding can be performed. On top of that, he gets pollied.

Therefore, the resin composition of the present invention can be effectively used as packaging materials, films, and the like.

〔Example〕

Next, examples of the present invention will be shown.

Examples 1-8 and Comparative Examples 1-4 (B) to 100 parts by weight of linear low density polyethylene.

Predetermined amounts of each of components (C) and (D) and 0.10 parts of calcium stearate were blended and granulated at a temperature of 180° C. using an extruder. The resulting pellets were granulated five times using an extruder at a temperature of 280''C.

Prepare sheets with a thickness of 2 cranes from the pellets before and after the repetition, and measure the yellowness (Y, 1.) according to JIS K71.
03), and the change is △Y.

■Displayed as.

In addition, the Ml after repeating granulation 5 times should be measured according to JIS
K6760), and the difference from the value of Ml (5 g/10 min) of the above linear low density polyethylene was expressed as ΔM1.

Next, a 30μ thick film was made from the pellets and JI
Elmendorf tear strength was measured according to S Z1702. In addition, MD in the table indicates the measured value in the flow direction, and TD indicates the measured value in the direction perpendicular to the flow.

Furthermore, blocking properties were measured by the following method.

Applying the vertical peeling method, a load of 9 kg was applied to the film surface, and after leaving it at a temperature of 60°C for 3 hours, it was set on a chuck for blocking measurement and peeled off using an autograph (pulling speed 200 x 1/10 x Table 1 shows the measurement results of the maximum values when

*1 Polyethylene LL-A: Ethylene unit content 96 mol% butene-1
Unit content: 2 mol% octene - 1 unit content
2 mol% MFR28, density 0.920 g/cnl,
Old 2.0g/10min LL-B: Ethylene unit content i
9B, 6 mol % propylene - 1 fl N containing
O, 8 mol% octene-1 unit content l O, 6 mol% MFR31, density 0.935 g/a (, former 2.h/1
0 minute LL-C: 80% by weight of the above LL-A and high pressure low density polyethylene (density 0.921 g/cnt).

Blend with 20% by weight (old 3.0 g/10 min) MFR31, density 0.935 g/ci, Ml 2.0 g
/10PE-1: Ethylene unit content fi 96.8
Mol%butene-1 unit containingffl 3.2mol%M
FR28, density 0.920g/cnl, old 2.0g/1
0 minutes*2 Phosphorus compound P-1: Tetrakis-(2,4-di-t-butylphenyl)4.4'-biphenylene diphosphite P-2: 4.4'-butylidenebis-(3-methyl-6- t-Butylphenyl ditridecyl) phosphite P-3: diatearyl pentaerythritol diphosphite P-4: bis-(2,4-di-t-butylphenyl)
Pentaerythritol diphosphite P-5: ) Lis-(2,4-di-t-butylphenyl)phosphite P-6: 〇-Ethyl-(4-hydroxy-3,5-t)
-butylbenzyl)phosphonic acid calcium salt *3 Phenolic antioxidant A-1: Octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate...Molecular weight 531 A-2: Penta Erythrityl tetrakis (3-(3
,5-di-t-butyl-4-hydroxyphenyl)probionate] ... Molecular weight 1178 A-3: 1,3.5-1-listyl-2,4゜6-
Tris(3,5-di(-butyl-4-hydroxybenzyl)) Benzene...Molecular weight 775 A-4: A mixture of the above A-1 and A-2 at a ratio of 1:2 A-571,3,5 -) Squirrel [ethylene-3-(3,5
-di-t-butyl-4-hydroxyphenyl)propionate] -s-triazine-2゜4,6- (IH,3H,5H)trione...Molecular weight 1040 A-6: 2.6-di-t-butyl- para-cresol...molecular weight 220 A-7: 2,2'-methylenebis(4-methyl-6
-t-butylphenol) Molecular weight 340 *4 Anhydrous amorphous aluminosilicate a: Sulfuric acid treated product of Na-4A type zeolite (average particle size 2.8 μm, range of 1/2 to 3/2 of the average particle size) 1 Made by Nippon Kagaku Gi Gi, with particles accounting for 90% of the total.

(Product name: NA-210P) b: Na-4A type zeolite treated with sulfuric acid (average particle size 2.0 μm, 80% of particles in the range of 1/2 to 3/2 of the average particle size, Suigen Kagaku) Industrial ■Made.

Product name Jilton AM (T)) c: Phosphoric acid treated product of Na-13X type zeolite (average particle size 2.2 μm, 95% of the particles are in the range of 1/2 to 3/2 of the average particle size) *5 The transparency of the film was significantly reduced.

Claims (2)

[Claims] (1) (A) Ethylene unit 90-99 mol%, carbon number 3
For 100 parts by weight of linear low density polyethylene consisting of 0.4 to 9.5 mol% of α-olefin units of ~4 and 0.4 to 9.5 mol% of α-olefin units of 6 to 12 carbon atoms, (B) 0.01 to 1.0 parts by weight of at least one phosphorus compound selected from the group consisting of phosphites, phosphonites, and phosphonic acid derivatives; (C) a molecular weight of 40 parts by weight;
0.01 to 1.0 parts by weight of 0 or more phenolic antioxidants and (D) 0.01 part by weight of anhydrous amorphous aluminosilicate obtained by acid-treating zeolite and having the basic particle form of zeolite. A polyethylene resin composition characterized in that ~2.0 parts by weight is added. (2) The polyethylene of component (A) has a melt flow ratio of 18 to 5.
2. The composition according to claim 1, which is a composition according to claim 1.