KR102414015B1 - Thermoplastic resin composition for film having excellent discoloration resistance and film using the same - Google Patents

Abstract

The present invention relates to a thermoplastic resin composition for a film and a film produced thereby. In one embodiment, the thermoplastic resin composition for a film comprises 100 parts by weight of a linear polyethylene resin, 0.01 to 5 parts by weight of a first antioxidant, and 0.05 to 5 parts by weight of a second antioxidant, and the first antioxidant is an amine-based antioxidant. and at least one of a complex antioxidant, wherein the second antioxidant comprises a phosphorus-based antioxidant, and the complex antioxidant comprises at least one of an antioxidant represented by Formula 1 and an antioxidant represented by Formula 2 .
(The above formulas 1 and 2 are as defined in the detailed description).

Description

Thermoplastic resin composition for film with excellent discoloration resistance and film formed therefrom

The present invention relates to a thermoplastic resin composition for a film and a film prepared using the same. More particularly, it relates to a thermoplastic resin composition for a film excellent in discoloration resistance and deterioration prevention effect of mechanical properties, and a film produced therewith.

Type low-density polyethylene (LDPE) can be prepared by copolymerizing ethylene and alpha-olefin at low pressure. The linear low-density polyethylene has excellent mechanical properties such as pinhole resistance, contaminant sealing properties, tear strength, impact resistance and hot tack properties when manufactured in a film form, so that it is used alone or , nylon, aluminum, biaxially stretched polypropylene film, and polyethylene terephthalate may be laminated on the surface of a substrate and used.

However, the polyethylene film composed of a single layer or a multilayer as described above has a discoloration phenomenon in which the color changes due to various causes, which causes various quality problems such as deterioration of appearance and deterioration of mechanical properties.

In general, when manufacturing and using a product containing a polyethylene resin, an antioxidant is prescribed to prevent denaturation of the polyethylene resin. Among them, the phenolic antioxidant serves to improve thermal stability and prevent resin denaturation by suppressing generation of radicals that may cause denaturation of polyethylene resin and molded articles manufactured using polyethylene resin. In addition, the phosphorus-based antioxidant serves to convert peroxide (Hyperoxide), a by-product produced when the phenol-based antioxidant reacts to inhibit radical generation, into a stable inert material, which inhibits the conversion of the peroxide back to radicals to further It imposes heat-resistance stability and maximizes the inhibition of resin denaturation. Although the composition of the above two antioxidants gives the property of preventing resin denaturation, the composition of some additives is still incomplete, so that the polyethylene resin is denatured, or the color of the molded article is changed due to the denaturation of the prescribed phenolic antioxidant. There was a problem with this.

As a prior art related to the present invention, there is Korean Patent Publication No. 2009-0089839 (published on August 24, 2009, title of the invention: flame retardant thermoplastic resin composition).

One object of the present invention is to provide a thermoplastic resin composition for a film having excellent discoloration resistance and resistance to gas fading.

Another object of the present invention is to provide a thermoplastic resin composition for a film having excellent mechanical strength.

Another object of the present invention is to provide a film formed from the thermoplastic resin composition for the film.

One aspect of the present invention relates to a thermoplastic resin composition for a film having excellent discoloration resistance. In one embodiment, the thermoplastic resin composition for a film comprises 100 parts by weight of a linear polyethylene resin, 0.01 to 5 parts by weight of a first antioxidant, and 0.05 to 5 parts by weight of a second antioxidant, and the first antioxidant is an amine-based antioxidant. and at least one of a complex antioxidant, wherein the second antioxidant comprises a phosphorus-based antioxidant, and the complex antioxidant comprises at least one of an antioxidant represented by the following Chemical Formula 1 and an antioxidant represented by the following Chemical Formula 2 Includes:

[Formula 1]

(In Formula 1, R ₁ to R ₁₆ are each independently hydrogen or a linear or branched alkyl group having 1 to 10 carbon atoms, and A ₁ is an alkylene group having 2 to 8 carbon atoms)

[Formula 2]

(In Formula 2, R ₁₇ to R ₂₈ are each independently hydrogen, or a linear or branched alkyl group having 1 to 10 carbon atoms, and L ₁ , L ₂ , L ₃ , L ₄ are linear or branched carbon atoms 1 is an alkylene group of ~10).

In one embodiment, the phosphorus-based antioxidant is tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite and distearyl pentaerythritol One or more of diphosphites may be included.

In one embodiment, the linear polyethylene resin is an ethylene homopolymer or a copolymer of ethylene and an alpha-olefin having 4 or more carbon atoms, and has a density of 0.915 to 0.930 g/cm 3 , and a melt index (190° C., 2.16 kg) measured according to ASTM D1238. ) may be 0.1 to 10 g/10 min.

In one embodiment, the first antioxidant and the second antioxidant may be included in a weight ratio of 1:2 to 1:6.

In one embodiment, the first antioxidant may include the complex antioxidant and the amine-based antioxidant in a weight ratio of 1:0.5 to 1:3.

In one embodiment, the amount of change in yellowness measured before and after 20 g of the thermoplastic resin composition for a film is quantified in an aluminum dish, and placed in a forced circulation oven (Convection Oven, Lab Tech) at 230° C. for 3 hours. (ΔY.I) is 30 or less, and the amount of change in yellowness measured before and after placing the thermoplastic resin composition for the film in a desiccator, filling with nitrogen oxide (NO _x ) gas, and placing it at 60° C. for 3 hours ( ΔY.I) may be 10 or less.

Another aspect of the present invention relates to a film produced by the thermoplastic resin composition for a film.

The thermoplastic resin composition for a film of the present invention has excellent discoloration resistance and resistance to gas fading, and has excellent mechanical strength. It can prevent the occurrence of various quality problems, such as deterioration of physical properties, so it can be particularly suitable for use in film manufacturing.

1 shows a discoloration mechanism when an antioxidant including a phenol-based compound is applied.
Figure 2 shows the reaction mechanism of the antioxidant containing the amine-based compound.

In describing the present invention, if it is determined that a detailed description of a related known technology or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

And the terms to be described later are terms defined in consideration of the functions in the present invention, which may vary depending on the intention or custom of the user or operator, so the definition should be made based on the content throughout this specification describing the present invention.

Thermoplastic resin composition for film

One aspect of the present invention relates to a thermoplastic resin composition for a film. In one embodiment, the thermoplastic resin composition for a film includes a linear polyethylene resin, a first antioxidant, and a second antioxidant. In one embodiment, the thermoplastic resin composition for a film includes 100 parts by weight of a linear polyethylene resin, 0.01 to 5 parts by weight of the first antioxidant, and 0.05 to 5 parts by weight of the second antioxidant.

Hereinafter, the constituent components of the thermoplastic resin composition for a film of the present invention will be described in more detail.

(A) Linear polyethylene resin

The linear polyethylene resin may be an ethylene homopolymer or a copolymer of ethylene and an alpha-olefin having 4 or more carbon atoms. For example, the linear polyethylene resin can be obtained by copolymerization with ethylene and 1-butene or isopentane.

For example, the linear low-density polyethylene resin may be prepared using a Ziegler-Natta catalyst, and the manufacturing method of the linear low-density polyethylene resin may be, for example, a gas phase method, a solution method, a slurry method, etc., if it is known in the art It is not particularly limited.

In one embodiment, the linear polyethylene resin may include a linear low-density polyethylene resin. For example, the linear polyethylene resin may have a density of 0.915 to 0.930 g/cm 3 . It has excellent moldability and mechanical strength under the above conditions, and may be suitable for use in film molding. In one embodiment, the linear polyethylene resin may have a melt index (190° C., 2.16 kg) measured according to ASTM D1238 of 0.1 to 10 g/10 min. Under the above conditions, the composition may have excellent mixability, moldability, and mechanical strength. For example, it may be 0.5-5 g/10min.

In one embodiment, the linear low-density polyethylene resin may have a polydispersity index (PDI, polydispersity index, Mw/Mn) of 1 to 6. Under the above conditions, weather resistance, chemical resistance, mechanical strength and moldability may be excellent.

(B) a first antioxidant

The first antioxidant includes at least one of an amine-based antioxidant and a complex antioxidant. In one embodiment, the amine-based antioxidant may include an alkyl amine-based antioxidant. For example, the alkylamine-based antioxidant includes oxidized bis(hydrogenated tallow alkyl)amine, oxidized bis(hydrogenated tallow alkyl)amine), and 4,4'-bis(α,α-dimethylbenzyl)diphenyl. amine, di-t-butyldiphenylamine, phenyl-α-naphthylamine, phenyl-α-naphthylamine and N,N′-diphenyl-p-phenylenediamine doesn't happen

In one embodiment, as the alkyl amine-based antioxidant, bis(C ₁₆ ~C ₁₈ )alkyl methyl amine oxide (or amine, bis(hydrogenated rape-oil alkyl)methyl, N-oxide (Amines, bis(hydrogenated rape-) oil alkyl)methyl, N-oxides)). The bis(C- ₁₆ ~ C ₁₈ )alkyl methyl amine oxide may be GENOX EP as a product.

1 below shows a discoloration mechanism when an antioxidant containing a phenol-based compound is applied. Referring to FIG. 1 , the antioxidant including a phenol-based compound may cause discoloration by generating radical products due to various factors such as nitrogen oxide.

On the other hand, Figure 2 below shows the reaction mechanism of the antioxidant containing the amine compound. Referring to FIG. 2 , it can be seen that even if the amine-based antioxidant is denatured by nitrogen oxide (NO _X ) and ultraviolet rays, the color change does not occur. Therefore, discoloration caused by NOx Gas Fading can be prevented if an amine-based antioxidant that does not contain a phenolic compound that causes discoloration is prescribed, or an antioxidant that transforms into a colorless compound even if denaturation occurs. have.

In one embodiment, the complex antioxidant includes at least one of an antioxidant represented by the following formula (1) and an antioxidant represented by the following formula (2):

[Formula 1]

(In Formula 1, R ₁ to R ₁₆ are each independently hydrogen or a linear or branched alkyl group having 1 to 10 carbon atoms, and A ₁ is an alkylene group having 2 to 8 carbon atoms)

[Formula 2]

(In Formula 2, R ₁₇ to R ₂₈ are each independently hydrogen, or a linear or branched alkyl group having 1 to 10 carbon atoms, and L ₁ , L ₂ , L ₃ , L ₄ are linear or branched carbon atoms 1 is an alkylene group of ~10).

The antioxidant represented by Formula 1 includes both a phenol-based antioxidant functional group and a phosphorus-based antioxidant functional group.

For example, the antioxidant represented by Formula 1 is 2-t-butyl-6-methyl-4-[3-(2,4,8,10-tetratert-butylbenzo-[d][1,3, 2]benzodioxaphosfepin-6-yl)oxypropyl]phenol (2-tert-butyl-6-methyl-4-[3-(2,4,8,10-tetratert-butylbenzo[d][1, 3,2]benzodioxaphosphepin-6-yl)oxypropyl]phenol) and the like. For example, the antioxidant represented by Formula 1 may include Sumilizer GP (manufactured by Sumitomo Chemical Co., Ltd.).

The antioxidant represented by Formula 2 includes both a phenol-based antioxidant functional group and a sulfur-based antioxidant functional group.

For example, the antioxidant represented by Formula 2 includes 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropionic acid thiodi-2,1-ethadinyl ester (3,5-Bis). (1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid thiodi-2,1-ethanediyl ester) and the like. For example, the antioxidant represented by Formula 2 includes IRGANOX 1035 (manufactured by BASF).

In addition, in one embodiment of the present invention, the complex antioxidant is an antioxidant including both a phenol-based antioxidant functional group and a phosphorus-based antioxidant functional group, and calcium bis(monoethyl(3,5)-di -t-Butyl-4-hydroxybenzyl)phosphonate (Calcium bis[monoethyl(3,5-di-tert-butyl-4-hydroxylbenzyl)phosphonate] may be further included.

[Formula 3]

The antioxidant represented by Formula 3 includes IRGANOX 1425.

In addition, in one embodiment of the present invention, the complex antioxidant is a compound containing both a phenol-based antioxidant functional group and a sulfur-based antioxidant functional group, and is 2-t-butyl-6-[(3-t-butyl) represented by the following Chemical Formula 4 -2-hydroxy-5-methyl-phenyl)thio]-4-methylphenol (2-tert-butyl-6-[(3-tert-butyl-2-hydroxy-5-methyl-phenyl)thio]-4 -methyl-phenol) and 2,4-bis(dodecylthiomethyl)-6-methylphenol (2,4-Bis(dodecylthiomethyl)-6-methylphenol) of Formula 5 may be further included:

[Formula 4]

[Formula 5]

In one embodiment, as a product usable as the compound of Formula 4, there is IRGANOX 1081 (manufactured by BASF), and as a product usable as the compound of Formula 5, there is IRGANOX 1726 (manufactured by BASF).

In one embodiment, the first antioxidant is included in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the linear polyethylene resin. When the first antioxidant is included in an amount of less than 0.01 parts by weight, the heat resistance stability of the present invention is reduced, and when it is included in an amount exceeding 10 parts by weight, the physical properties of the linear ethylene and the film to be prepared may be reduced. For example, 0.01 to 0.5 parts by weight may be included.

In one embodiment, the first antioxidant may include the complex antioxidant and the amine-based antioxidant in a weight ratio of 1:0.5 to 1:3. When included in the above range, the heat resistance, discoloration resistance and resistance to gas fading of the present invention may be excellent, and mechanical strength may be excellent.

(C) a second antioxidant

The second antioxidant includes a phosphorus-based antioxidant. In one embodiment, the phosphorus-based antioxidant includes tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite and distearyl pentaeryth. one or more of ritol diphosphite.

The second antioxidant is included in an amount of 0.05 to 5 parts by weight based on 100 parts by weight of the linear polyethylene resin. When the second antioxidant is included in less than 0.05 parts by weight, the efficiency of converting the peroxide into an inert compound is reduced, the effect of improving heat resistance stability is reduced, and when it is included in more than 5 parts by weight, the phosphorus-based antioxidant denaturation due to hydrolysis As a result, the physical properties of the linear polyethylene and the film produced may be deteriorated. For example, 0.05 to 0.5 parts by weight may be included.

In one embodiment, the second antioxidant may be included in a higher content than the first antioxidant. For example, the first antioxidant and the second antioxidant may be included in a weight ratio of 1:2 to 1:6. When included in the above weight ratio, it may have excellent resistance to discoloration and gas fading, and excellent mechanical strength. For example, it may be included in a weight ratio of 1:2 to 1:4. For another example, it may be included in a weight ratio of 1:2 to 1:3.

In one embodiment, 20 g of the thermoplastic resin composition for the film is quantified in an aluminum dish, and placed in a forced circulation oven (Convection Oven, Lab Tech) at 230° C. for 3 hours before and after using a colorimeter, respectively. Thus, the measured yellowness gradient (ΔY.I) may be 30 or less. For example, it may be 23 or less.

In one embodiment, the amount of change in yellowness is measured by measuring 20 g of a sample of the thermoplastic resin composition of the present invention in an aluminum dish (Dish) and then measuring the initial yellowness (YI ₀ ), and then forced circulation oven (Convection Oven, Lab Tech) at 230 ° C. for 3 hours, the sample was cooled and the yellowness (YI ₁ ) was measured using a colorimeter, and then the amount of yellowness change (Yellow Index, ΔY.I) according to the following measurement formula 1 ) can be measured:

[Equation 1]

Yellowness change (Yellow Index, ΔY.I) = YI ₀ -YI ₁

In one embodiment, the amount of change in yellowness is measured using a colorimeter before and after the thermoplastic resin composition for the film is placed in a desiccator and filled with nitrogen oxide gas at 60° C. for 3 hours. The yellowness gradient (ΔY.I) may be 10 or less. For example, it may be 7 or less.

In one embodiment, the amount of change in yellowness is measured by placing a sample of the thermoplastic resin composition for the film in a desiccator and measuring the initial yellowness (YI ₀ ), then filling with nitrogen oxide gas, and then at 60° C. for 3 hours After being placed for a while, and measuring the yellowness (YI ₂ ) of the sample using a colorimeter, the amount of change in yellowness (Yellow Index, ΔY.I) can be measured according to the following Equation 2:

[Measurement Formula 2]

Yellowness change (Yellow Index, ΔY.I) = YI ₀ -YI ₂

Another aspect of the present invention relates to a film produced by a thermoplastic resin composition for film.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is presented as a preferred example of the present invention and cannot be construed as limiting the present invention in any sense.

Example and comparative example

The components used in Examples and Comparative Examples are as follows.

(A) Linear polyethylene resin: a melt index of 1.0 g/10 min, a density of 0.920 g/cm 3 , and a linear low-density polyethylene prepared by ethylene homopolymerization was used.

(B) a first antioxidant

(B1) Amine-based antioxidant: As an alkylamine-based antioxidant, oxidized bis(hydrogenated tallow alkyl)amine and oxidized bis(hydrogenated tallow alkyl)amine) were used.

(B2) 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropionic acid thiodi-2,1-etha containing both a phenolic antioxidant functional group and a sulfur-based antioxidant functional group as a complex antioxidant A dinyl ester (3,5-Bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid thiodi-2,1-ethanediyl ester (irganox 1035, manufactured by BASF)) was used.

(B3) 2-t-butyl-6-methyl-4-[3-(2,4,8,10-tetratert-butylbenzo) containing both a phenolic antioxidant functional group and a phosphorus antioxidant functional group as a complex antioxidant -[d][1,3,2]benzodioxaphosphepin-6-yl)oxypropyl]phenol (2-tert-butyl-6-methyl-4-[3-(2,4,8,10-) tetratert-butylbenzo[d][1,3,2]benzodioxaphosphepin-6-yl)oxypropyl]phenol), product name: Sumilizer GP (manufactured by Sumitomo Chemical) was used.

(C) Second antioxidant: distearyl pentaerythritol diphosphite was used as a phosphorus-based antioxidant.

(D) Octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was used as a phenolic antioxidant.

Example 1-3 and comparative example 1-7

The composition of the components and contents according to Table 1 below was prepared in the form of pellets having a diameter of about 4 mm using a single screw extruder to prepare a composition specimen.

In addition, with respect to Examples 1 to 3 and Comparative Examples 1 to 7, physical properties were measured in the following manner, and the results are shown in Table 2 below.

How to measure physical properties

(1) Thermal stability: After 20 g of the samples of the Examples and Comparative Examples were quantified in an aluminum dish, the initial yellowness (YI ₀ ) was measured, and then the forced circulation oven (Convection Oven, Lab Tech) was 230 ° C. conditions was stored for 3 hours. Thereafter, the samples of the Examples and Comparative Examples were cooled, and the yellowness (YI ₁ ) was measured using a colorimeter, and then the amount of change in yellowness (Yellow Index, ΔY.I) was measured according to the following formula.

[Equation 1]

Yellowness change (Yellow Index, ΔY.I) = YI ₀ -YI ₁

(2) NOx Gas Fading Characteristics: The samples of the Examples and Comparative Examples are placed in a desiccator, and the initial yellowness (YI ₀ ) is measured, then filled with nitrogen oxide gas, and placed at 60° C. for 3 hours did. After measuring the yellowness (YI ₂ ) of the sample using a colorimeter, the amount of change in yellowness (Yellow Index, ΔY.I) was measured according to the following formula.

[Measurement Formula 2]

Yellowness change (Yellow Index, ΔY.I) = YI ₀ -YI ₂

Referring to the results of Table 2, when the first antioxidant including the complex antioxidant and the second antioxidant including the phosphorus antioxidant are applied to the linear low-density polyethylene resin of the present invention, heat resistance stability and NOx Gas Fading It was found that the characteristics were maximized, and problems such as deterioration of physical properties due to discoloration or resin deterioration could be completely solved.

On the other hand, in Comparative Examples 1, 3 and 5 in which the content of the first antioxidant of the present invention is exceeded, and Comparative Example 2 in which the first antioxidant of the present invention is not applied, heat resistance stability due to oxidation of the antioxidant is lowered. Could know. In addition, in Comparative Example 4 to which the second antioxidant of the present invention was not applied, heat resistance stability was lowered, and in Comparative Example 5 exceeding the content of the second antioxidant of the present invention, the discoloration property by NOx gas was excellent, but heat resistance It was found that the resin was denatured because stability was not secured. In addition, in the case of Comparative Example 6 to which the phenolic antioxidant was applied and Comparative Example 7 to which the antioxidant was not applied, it was found that the antioxidant reacted with NOx Gas to cause severe discoloration.

Looking at the above results, it can be seen that when the antioxidant of any one of the first antioxidant and the second antioxidant of the present invention is not combined or is included in an amount outside the scope of the present invention, the discoloration resistance is significantly reduced. have.

Simple modifications or changes of the present invention can be easily carried out by those of ordinary skill in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (7)

100 parts by weight of a linear polyethylene resin,
0.01 to 5 parts by weight of an amine-based antioxidant, an antioxidant represented by the following Chemical Formula 2, or 0.01 to 5 parts by weight of a first antioxidant comprising a combination of an amine-based antioxidant and an antioxidant represented by the following Chemical Formula 1;
0.05 to 5 parts by weight of a second antioxidant including a phosphorus antioxidant;
The amine-based antioxidant is oxidized bis(hydrogenated tallow alkyl)amine, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, di-t-butyldiphenylamine, phenyl-α- comprising at least one of naphthylamine and N,N'-diphenyl-p-phenylenediamine;
The phosphorus-based antioxidant is one of tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite and distearyl pentaerythritol diphosphite A thermoplastic resin composition for a film, comprising:
[Formula 1]

(In Formula 1, R1 to R16 are each independently hydrogen or a linear or branched alkyl group having 1 to 10 carbon atoms, and A1 is an alkylene group having 2 to 8 carbon atoms)
[Formula 2]

(In Formula 2, R17 to R28 are each independently hydrogen or a linear or branched alkyl group having 1 to 10 carbon atoms, and L1, L2, L3, and L4 are linear or branched alkylene groups having 1 to 10 carbon atoms. ).
delete The method according to claim 1, wherein the linear polyethylene resin is an ethylene homopolymer or a copolymer of ethylene and an alpha-olefin having 4 or more carbon atoms, and has a density of 0.915 to 0.930 g/cm 3 , and a melt index (190° C., 2.16kg) is a thermoplastic resin composition for a film, characterized in that 0.1 to 10g/10min.
The thermoplastic resin composition for a film according to claim 1, wherein the first antioxidant and the second antioxidant are included in a weight ratio of 1:2 to 1:6.
The method according to claim 1, wherein the combination of the amine-based antioxidant and the antioxidant represented by Formula 1 comprises the antioxidant represented by Formula 1 and the amine-based antioxidant in a weight ratio of 1:0.5 to 1:3 A thermoplastic resin composition for a film.
According to claim 1, wherein 20 g of the thermoplastic resin composition for the film is quantified in an aluminum dish, and yellowness measured before and after being placed in a forced circulation oven (Convection Oven, Lab Tech) at 230° C. for 3 hours. The amount of change (ΔY.I) of is 30 or less,
The amount of change in yellowness (ΔY.I) measured before and after the thermoplastic resin composition for the film is placed in a desiccator and filled with nitrogen oxide (NO _x ) gas at 60° C. for 3 hours is 10 or less, characterized in that A thermoplastic resin composition for a film.
A film produced by the thermoplastic resin composition for a film of any one of claims 1 and 3 to 6.

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