JP2006104408A - Resin composition for container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for a container, having excellent property balance intrinsically required for the container, especially having excellent properties of moldability, low contamination metal-eluting properties and weather resistance. <P>SOLUTION: The resin composition is obtained by adding 0.01-0.25 wt.% hindered phenol-based antioxidant and 0.15-0.25 wt.% hindered amine-based photostabilizer to a polyethylene having 1-10 g/10 min melt index at 190°C under 21.6 kg load, and 0.930-0.980 g/cm<SP>3</SP>density, and has ≤300 ppm metal content. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin composition for container containers.

  A typical example of a container container is a thin plastic container constituting a pallet container as shown in Patent Document 1, for example, and there are many large blow products of 1000L or more. High-density polyethylene is mainly used as a material for these container containers, and high-density polyethylene that has been conventionally used as a material for drums and fuel tanks is often used after being diverted.

  A pallet container typically includes a thin plastic container, an outer wire grid support surface, and a floor pallet, and various plastic containers are used.

On the other hand, in Patent Document 2, in the semiconductor device industry field, the precision industrial parts field, etc., it is suitable for molding containers used for cleaning parts, and in particular, the antioxidant property during molding and the solvent or As a polyethylene resin composition having both dissolution resistance to a solution, polyethylene having a density of 0.93 to 0.98 g / cm ³ and a melt index of 0.05 to 2.5 g / 10 min has an average molecular weight of 1800 or more. A low-eluting polyethylene resin composition comprising 0.005 to 0.8% by weight of a hindered amine light stabilizer is added.

  Patent Document 3 discloses a phenol-based high-density polyethylene resin composition suitable for a large blow-molded clean container that is excellent in productivity such as surface properties and moldability, mechanical strength such as rigidity and impact resistance, and cleanliness. A large blow containing an antioxidant in an amount of 0.01 to 0.05% by weight based on the high density polyethylene and a melt index (190 ° C., 21.6 kg) of the high density polyethylene of 1.0 to 20 g / 10 min. A polyethylene resin composition for molded clean containers is disclosed.

Japanese National Patent Publication No. 6-506901 JP-A-6-220263 Japanese Patent Laid-Open No. 11-43560

  However, in high density polyethylene used for drums and fuel tanks, it is difficult to say that the performance required for container containers such as moldability, low contamination metal contamination in additives and weather resistance are well balanced. The conventional polyethylene resin composition is still insufficient.

  An object of the present invention is to provide a resin for a container container that has an excellent performance balance originally required for a container container, and in particular, the performance of moldability, contamination metal low elution property and weather resistance in additives is now. It is to provide a new material which is at a level superior to the materials used so far.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found a resin composition for container containers excellent in moldability / contaminant metal low elution property / weather resistance in additives, and completed the present invention. .

That is, the present invention firstly provides hindered phenolic antioxidant to polyethylene having a melt index of 11.6 g / 10 min at 21.6 kg load at 190 ° C. and a density of 0.930-0.980 g / cm ^3. Container containing 0.01 to 0.25% by weight of an agent and 0.15 to 0.25% by weight of a hindered amine light stabilizer, and having a metal content of 300 ppm by weight or less It is a resin composition for containers.

  Secondly, the present invention is the first container container resin composition having an aluminum content of 0.2 ppm by weight or less.

  3rdly, this invention is the said 1st or 2nd resin composition for container containers whose iron content is 0.2 weight ppm or less.

  Fourthly, the present invention is characterized in that the retention time of a tensile elongation residual ratio of 80% or more after an exposure test using a laboratory light source according to JIS K7350-4 is 1000 hours or more. Any one of the container container resin compositions.

  Fifth, according to the present invention, the container container resin composition according to any one of the first to fourth aspects, wherein a retention time of a tensile elongation residual ratio of 80% or more by an Arizona outdoor exposure test is 5 years or more. It is.

  Sixthly, the present invention is characterized in that the aluminum elution amount after 1000 hours at 40 ° C. to the container container contents is 1.0 weight ppb or less with respect to the container container contents. It is the resin composition for container containers of 5th.

  Seventhly, the present invention is characterized in that the amount of iron elution after 40 hours at 40 ° C. into the container container contents is 1.0 weight ppb or less with respect to the container container contents. It is the resin composition for container containers in any of the 6th.

  Eighth, the present invention is a blow molded product molded from any one of the first to seventh resin compositions.

  Ninthly, the present invention is a container container molded from any one of the first to eighth resin compositions.

  By using the polyethylene resin composition of the present invention, a container container excellent in mechanical properties such as surface properties, moldability, etc., rigidity, impact resistance, etc., cleanliness and weather resistance, particularly a large blow molded clean container is suitable. Can be molded.

Hereinafter, the present invention will be described in detail.
The resin composition of the present invention has a hindered phenolic antioxidant added to polyethylene having a melt index of 11.6 g / 10 min at 190 ° C. and a density of 0.930 to 0.980 g / cm ^3. It is a resin composition for container containers having 0.01 to 0.25% by weight and a hindered amine light stabilizer added to 0.15 to 0.25% by weight and a metal content of 300 ppm by weight or less. .

The polyethylene used in the present invention is a high density polyethylene having a density of 0.930 to 0.980 g / cm ³ . If the density is less than 0.930 g / cm ³ , the rigidity of the molded product is insufficient, and if the density exceeds 0.980 g / cm ³ , the environmental stress cracking property which is a characteristic of polyethylene is inferior. Cracks are likely to occur. The polyethylene used in the present invention has a melt index (according to JIS K6760, measured at a temperature of 190 ° C. and a load of 21.6 kg) of 1 to 10 g / 10 minutes, preferably 2 to 10/10 minutes. When the melt index is less than 1 g / 10 minutes, the extrusion amount during molding is inferior. On the other hand, when the melt index exceeds 10 g / 10 min, the melt tension is lowered and it becomes difficult to mold a large container (1000 L or more).

The hindered phenolic antioxidant used in the present invention is a phenolic compound having a radical scavenging function and a sterically constrained structure, and having a t-butyl group at the ortho position with respect to the phenolic hydroxyl group. A compound having an alkylphenol structure in which at least one bulky alkyl group is substituted in the molecule is preferable, for example,
Tetrakis- [methylene (3,5-di-t-butyl-4-hydroxyhydro-cinnamate)] methane (for example, IRGANOX 1010 manufactured by Ciba Geigy Japan),
n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate (for example, IRGANOX 1076 manufactured by Ciba Geigy Japan),

2,2′-methylene-bis (4-methyl-6-tert-butylphenol) (for example, Yoshinox 2246R manufactured by Yoshitake Pharmaceutical Co., Ltd.),
1,3,5-tris (3,5-di-t-butyl-4-hydroxy-benzyl) -S-triazine-2,4,6- (1H · 3H · 5H) trione (for example, manufactured by Asahi Denka Co., Ltd.) ADK STAB AO-20),

4,4′-butylidene-bis- (3-methyl-6-tert-butyl-phenol) (for example, Sumitizer BBM-S manufactured by Sumitomo Chemical Co., Ltd.)
1,3,5-tris (4-t-butyl-3-hydroxy-2,6-di-methyl-benzyl) -isocyanurate (for example, CYANOX 1790 manufactured by ACC)
Etc. The hindered phenolic antioxidant used in the present invention can be used singly or in combination of two or more.

Particularly preferred among the hindered phenolic antioxidants are tetrakis- [methylene (3,5-di-t-butyl-4-hydroxyhydro-cinnamate)] methane (IRGANOX 1010),
n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate (IRGANOX1076).

  The hindered phenol antioxidant used in the present invention preferably has a metal content of 10 ppm by weight or less. If the metal content exceeds 10 ppm by weight, metal elution becomes significant with respect to the contents of the container container, which is inconvenient as a clean container. Examples of the metal that can be contained in the hindered phenolic antioxidant used in the present invention include Group 8, 9, 10 or 13 metals of the periodic table, and the metal content thereof is 10 ppm by weight or less. It is preferable. By using a hindered phenol-based antioxidant having a metal content of 10 ppm by weight or less, the aluminum elution amount into the container container contents is 0.1 weight ppb or less with respect to the container container contents, and the container It is preferable that the iron elution amount into the container contents is 0.1 weight ppb or less with respect to the container container contents.

  In the present invention, the amount of hindered phenol antioxidant added to polyethylene is 0.01 to 0.25% by weight, preferably 0.02 to 0.25% by weight. If the amount of hindered phenolic antioxidant added to polyethylene is less than 0.01% by weight, heat generation and oxidative degradation are likely to occur during molding, even if the molded product has good elution resistance to the solvent or solution. Further, if the amount added exceeds 0.25% by weight, even if there is no exothermic heat and oxidative deterioration during molding, the solvent or solution lacks elution resistance, and the amount of elution is large, so that the object of the present invention is sufficiently achieved. It is hard to do.

The hindered amine light stabilizer used in the present invention (hereinafter sometimes referred to as HALS) is an amine compound having a sterically constrained structure, such as a compound shown in JP-A-7-286052. In particular, 2,2,6,6-tetraalkylpiperidine derivatives having a molecular weight of 250 or more and having a substituent at the 4-position are mentioned. Among them, all hydrogens on the 2-position and 6-position carbons of the piperidine are methyl groups. Compounds having a structure substituted with are preferred, for example
Dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate (for example, TINUVIN622LD manufactured by Ciba Geigy Japan),

  Poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl)} {(2,2,6,6-tetramethyl-4- Piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] polycondensate (for example, CHIMASSORB 944LD manufactured by Ciba-Geigy Japan),

  N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro- 1,3,5-triazine condensate (for example, CHIMASSORB119FL manufactured by Ciba Geigy Japan),

  1,2,6,6,6-pentamethyl-4-biperidyl / β, β, β, β-tetramethyl-3,9- [2,4,8,10-tetraoxaspiro (5,5) undecane] Diethyl (mixed) -1,2,3,4-butanetetracarboxylate (Asahi Denka Co., Adeka Stub LA-63),

  2,2,6,6-tetramethyl-4-biperidyl / β, β, β, β-tetramethyl-3,9- [2,4,8,10-tetraoxaspiro (5,5) undecane] diethyl (Mixed) -1,2,3,4-butanetetracarboxylate (Asahi Denka Co., ADK STAB LA-68),

  Poly {[6-morpholino-2,4-diyl] [4- (2,2,6,6-tetramethylbiperidyl) iminohexamethylene] [4- (2,2,6,6-tetramethylbiphenyl) Peridyl) imino]} (Cyasorb UV3346 manufactured by American Cyanamide Chemical Co.). The hindered amine light stabilizer used in the present invention can be used singly or in combination of two or more.

  Among the hindered amine light stabilizers, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl)} { (2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] polycondensate (CHIMASSORB 944LD).

  The hindered amine light stabilizer used in the present invention preferably has a metal content of 10 ppm by weight or less. If the metal content exceeds 10 ppm by weight, metal elution becomes significant with respect to the contents of the container container, which is inconvenient as a clean container. Examples of the metal that can be contained in the hindered amine light stabilizer of the present invention include metals of Group 8, 9, 10 or 13 of the periodic table, and the metal content is preferably 10 ppm by weight or less. By using these hindered amine antioxidants, the aluminum elution amount into the container container contents is 0.1 wt ppb or less, preferably 0.08 wt ppb or less with respect to the container container contents. It is preferable that the iron elution amount into the container contents is 0.1 weight ppb or less, preferably 0.08 weight ppb or less, with respect to the container container contents.

  The hindered amine light stabilizer used in the present invention suitably has an average molecular weight of 250 or more, preferably 1800 or more, more preferably 2000 or more. If the hindered amine light stabilizer has an average molecular weight of less than 250, the molded product lacks elution resistance to the solvent or solution of the molded product even if there is no oxidative deterioration during molding, and the elution amount is large. It is difficult to achieve.

  The amount of hindered amine light stabilizer added to polyethylene is 0.15 to 0.25% by weight, preferably 0.17 to 0.23% by weight, more preferably 0.18 to 0.22% by weight. %. When the amount of the hindered amine light stabilizer added to polyethylene is less than 0.15% by weight, although the elution resistance to the solvent or solution of the molded article is good, the weather resistance is poor and the performance as a container container cannot be satisfied. Further, when the amount added exceeds 0.25% by weight, although the weather resistance is good, the molded product lacks the elution resistance to the solvent or solution, and the elution amount is large, so that the object of the present invention is sufficiently achieved. It is hard to do.

  The resin composition of the present invention has a metal content of 300 ppm by weight or less. If it exceeds 300 ppm by weight, metal elution into the container container contents will increase, which is not preferable as a container container. Examples of the metal include all kinds of metals. For example, sodium, magnesium, aluminum, silicon, calcium, vanadium, iron, nickel, copper, zinc, barium and the like are more preferable. These metals can be analyzed by a general metal analysis method. The resin composition of the present invention preferably has an aluminum content of 0.2 ppm by weight or less, preferably 0.15 ppm by weight or less as a clean container. Further, the resin composition of the present invention preferably has an iron content of 0.2 ppm by weight or less, preferably 0.15 ppm by weight or less as a clean container. Furthermore, the resin composition of the present invention has a titanium content of 1 ppm by weight or less, a magnesium content of 1 ppm by weight or less, a chromium content of 20 ppm by weight or less, or a silicon content of 250 ppm by weight or less. , Cleanliness is improved and preferable.

  The container container obtained by the resin composition of the present invention has an aluminum elution amount after 40 hours at 40 ° C. (particularly into water) of the container container content of 1.0 weight ppb with respect to the container container content. The following is preferable as a clean container. Moreover, it is preferable as a clean container that the amount of iron elution after 40 hours at 40 ° C. to the container container contents (particularly to water) is 1.0 weight ppb or less with respect to the container container contents. These elution amounts can be suppressed to a predetermined amount by suppressing the amount of metal contained in the resin composition of the present invention.

  The resin composition of the present invention has a retention time of 80% or more of the tensile elongation residual ratio after an exposure test with a laboratory light source in accordance with JIS K7350-4, usually 1000 hours or more, preferably 1500 hours or more, more preferably 2000 hours. That's all. In addition, the resin composition of the present invention has a retention time of 80% or more in the tensile elongation residual ratio by Arizona outdoor exposure test of 5 years or more, preferably 6 years or more, and more preferably 7 years or more.

  Various additives such as other antioxidants, neutralizing agents and other weathering agents can be added to the resin composition of the present invention as desired. However, each of these additives should be kept at 0.2 wt% or less, preferably 0.1 wt% or less, more preferably 0.05 wt% or less. Also, the amount of impurities such as catalyst residues in polyethylene should be kept at 0.2% by weight or less, preferably 0.1% by weight or less, more preferably 0.05% by weight or less. When these additives and impurities exceed 0.2% by weight, the amount of elution of the molded product increases, which is not preferable.

  The polyethylene constituting the resin composition of the present invention preferably contains a chromium-based catalyst, a so-called Philips catalyst, particularly a polyethylene produced by a chromium-based catalyst not containing a metal of Group 8, 9, 10 or 13 of the periodic table.

  The resin composition of the present invention is kneaded with various additives such as hindered phenolic antioxidants and hindered amine light stabilizers and other antioxidants, neutralizing agents, and other weathering agents, if necessary, in polyethylene, It can be molded by a hollow molding machine or the like to obtain a container (industrial chemical can), or it can be processed into a molded product such as industrial parts and equipment with high chemical resistance.

  The resin composition of the present invention can have a more favorable effect on molding of a product by molding in a clean environment, for example, a clean room of cleanliness ISO class 7 or US Federal Standard FS-209D class 10000. Preferably, the effect can be further improved by molding in a clean room of cleanliness ISO class 6 or US federal standard FS-209D class 1000, more preferably cleanliness ISO class 5 or US federal standard FS-209D class 100. A more excellent effect can be obtained by molding in a clean room or a clean room of higher cleanliness.

  The resin composition of the present invention can be made into a blow molded product, particularly a large blow molded product by a blow molding method. The obtained blow molded product has mechanical strength such as surface properties, rigidity, impact resistance and cleanliness, and It is excellent in weather resistance and can be suitably used as a container container or a clean container. The container container of the present invention is particularly suitable for pallet containers.

(Example)
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to an Example.

IRGANOX1010 as a hindered phenolic antioxidant is weighted in high density polyethylene obtained by polymerization with a Philips catalyst at a density of 0.956 g / cm ³ and a melt index (190 ° C., 21.6 kg) of 5 g / 10 min. Ratio of 0.1 wt% (aluminum content at the time of addition 0.3 wtppm, iron content 0.14 wtppm), CHIMASSORB944LD as a hindered amine light stabilizer 0.2 wt% (at the time of addition) What added aluminum content 0.2 weight ppm and iron content 0.14 weight ppm) is shape | molded with a large sized hollow molding machine (NB120 made by Nippon Steel Works, Ltd.), and the weight of the cube shape with an internal volume of 1000L. A 0 kg large blow container was obtained.
For metal analysis, about 1 g of a sample was weighed into a quartz beaker and thermally decomposed with sulfuric acid and nitric acid. Each element was measured by ICP-MS with 50 ml of pure water. Regarding silicon, about 0.5 g of a sample was weighed into a platinum crucible and carbonized with sulfuric acid. Sodium carbonate was added and melted, dissolved in pure water, acidified with hydrochloric acid, and measured by ICP-AES. As a result, the metal content of the container is 300 ppm by weight or less, sodium is 1 ppm by weight, magnesium is 1 ppm by weight, aluminum is 0.2 ppm by weight, silicon is 250 ppm by weight, calcium is 1 Weight ppm or less, Titanium 1 ppm or less, Vanadium 1 ppm or less, Chromium 20 ppm or less, Iron 0.2 ppm or less, Nickel 1 ppm or less, Copper 1 ppm or less, Zinc 1 ppm by weight or less, barium was 1 ppm by weight or less.

  900 L of ultrapure water containing 0.5 μm or less of particles of 1 particle or less per ml was put in the obtained container and shaken well, and then the water was discarded. After repeating this operation 5 times, 900 L of ultrapure water was added and allowed to stand at 40 ° C. for 1000 hours, and then the metal in the ultrapure water was measured. For the metal measurement, a part of the ultrapure water was collected, evaporated by heating, thermally decomposed with sulfuric acid and nitric acid, diluted with pure water, and measured by ICP-MS. The aluminum content or the iron content in 900 L of ultrapure water was x 1 wt ppb or more, and the one less than 1 wt ppb was marked as ◯. The above operation was performed in a clean environment.

  On the other hand, a No. 2 type test piece-shaped test piece based on JIS K7133 was produced using the above composition. The test piece was produced by compressing the resin composition and then punching it with a punching blade. In accordance with JIS K7350-4, after an exposure test using a laboratory light source (using a Sunshine Weather Ometer WEL-300H (SWOM) manufactured by Suga Test Instruments Co., Ltd., exposing a test piece to an open frame carbon arc lamp and carrying out water spraying) The retention time of 80% or more of the tensile elongation residual rate was measured and evaluated as weather resistance.

  Furthermore, the test piece of No. 2 type test piece shape based on JISK7133 was produced using the said composition. The test piece was produced by compressing the resin composition and then punching it with a punching blade. Using this test piece, we measured the retention time of 80% or more of residual elongation after exposure test (exposed to the south of Phoenix, Arizona, direct sunlight, angle of 34 degrees) at an exposure test site in Arizona, USA. Evaluation of sex.

Moreover, oxidation deterioration was measured by the presence or absence of the torque stabilization period when kneading the said composition at 230 degreeC and 50 rpm using the Laboplast mill by Toyo Seiki Seisakusho. In the lab plast mill, if there is a torque stabilization period until the resin melts and deterioration due to crosslinking and cutting occurs, the effect of the antioxidant is recognized, and if there is no torque stabilization period, the antioxidant Therefore, the container forming suitability was determined.
The results are shown in Table 1.

  The same procedure as in Example 1 was performed except that the amount of CHIMASSORB 944LD added in Example 1 was changed to 0.25% by weight. The results are shown in Table 1.

  The same procedure as in Example 1 was performed except that the amount of CHIMASSORB 944LD added in Example 1 was changed to 0.15% by weight. The results are shown in Table 1.

  The same operation as in Example 1 was conducted except that the amount of IRGANOX 1010 added in Example 1 was 0.01% by weight. The results are shown in Table 1.

  The same operation as in Example 1 was performed except that the amount of IRGANOX 1010 added in Example 1 was changed to 0.25% by weight. The results are shown in Table 1.

Comparative Example 1
The same procedure as in Example 1 was performed except that the amount of CHIMASSORB 944LD added in Example 1 was 0.1% by weight. The results are shown in Table 2.

Comparative Example 2
The same procedure as in Example 1 was performed except that the amount of CHIMASSORB 944LD added in Example 1 was changed to 0.5% by weight. The results are shown in Table 2.

Comparative Example 3
The same operation as in Example 1 was performed except that the amount of IRGANOX 1010 added in Example 1 was 0% by weight. The results are shown in Table 2.

Comparative Example 4
The same procedure as in Example 1 was performed except that the amount of CHIMASSORB 944LD added in Example 1 was changed to 0% by weight. The results are shown in Table 2.

Claims (9)

0.01 to 0.25 wt.% Of hindered phenolic antioxidant in polyethylene having a melt index of 11.6 g / 10 min at 190 ° C. and a density of 0.930 to 0.980 g / cm ^3. % And a hindered amine light stabilizer are added in an amount of 0.15 to 0.25% by weight, and the metal content is 300 ppm by weight or less.   The resin composition for container containers according to claim 1, wherein the aluminum content is 0.2 ppm by weight or less.   The resin composition for container containers according to claim 1 or 2, wherein the iron content is 0.2 ppm by weight or less.   The container container according to any one of claims 1 to 3, wherein a retention time of a tensile elongation residual ratio of 80% or more after an exposure test with a laboratory light source in accordance with JIS K7350-4 is 1000 hours or more. Resin composition.   The resin composition for container containers according to any one of claims 1 to 4, wherein a retention time of a tensile elongation residual ratio of 80% or more by an Arizona outdoor exposure test is 5 years or more.   The container according to any one of claims 1 to 5, wherein an aluminum elution amount after 1000 hours at 40 ° C to the container container contents is 1.0 weight ppb or less with respect to the container container contents. Resin composition for containers.   The container according to any one of claims 1 to 6, wherein the iron elution amount after 1000 hours at 40 ° C to the container container contents is 1.0 weight ppb or less with respect to the container container contents. Resin composition for containers.   A blow-molded product molded from the resin composition according to claim 1.   A container container molded from the resin composition according to claim 1.