JPS60112843A - Polypropylene resin composition - Google Patents

Abstract

PURPOSE:To provide titled composition of high radiation resistance and transparency, comprising polypropylene resin, ethylene-1-butene copolymer, specific sorbitol derivative, triaryl phosphite, and hindered amine stabilizer. CONSTITUTION:A composition consisting of (A) 100pts.wt. of polypropylene resin and (B) 0.5-50 (pref. 1-30)pts.wt. of ethylene-1-butene copolymer (with an ethylene content 70-97mol% and density 0.82-0.95g/cm<3>) is incorporated with each 0.01-4 (pref. 0.02-2)pts.wt. of (C) sorbitol derivative of formula (R is H or 1-18C alkyl) [e.g. 1,3,2,4-di(ethylbenzylidene)sorbitol], (D) tris (2,4-di-t-butylphenyl)phosphite, and (E) dimethyl succinate 2-(4-hydroxy 2,2,6,6-tetramethyl-1- piperizyl)ethanol condensate followed by homogeneous dispersion then melting in an extruder to effect pelletization.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polypropylene resin composition that has almost no oxidation, is stable against long-term thermal history after irradiation, and has excellent transparency.

Polypropylene morning fat has good mechanical properties, heat resistance, and chemical resistance, and is also highly hygienic. Widely used in equipment, etc.

However, when used as food containers, medical instruments, etc., it is important to be able to confirm that there are no dust or other foreign substances mixed into the contents, and to prevent the container from interfering with the correct color tone of the contents. Undesirable.

For this reason, polypropylene resins with good transparency are desired in these applications.

Furthermore, food containers 1. Considering the intended use, medical instruments are usually sterilized before use. For this purpose, heat sterilization using steam, gas sterilization using ethylene oxide gas, which has a strong sterilizing effect, and hydrogen peroxide are used. Sterilization methods are being used.

In recent years, radiation sterilization methods, in which sterilization is carried out by irradiation with radiation, have come into use, and are increasingly being used for tableware containers and medical instruments. By the way, polypropylene resin
It is stable when it comes to steam sterilization and waste sterilization using water vapor, but it is unstable when it comes to radiation, such as radiation sterilization 1-', I
If it is exposed to water, it has the disadvantage of causing yellowing and deterioration of physical properties.

In particular, with regard to low physical properties, by irradiating radiation, the surface area of 11゛1゜8111゜ becomes less than half of that before irradiating radiation, and if further heat is applied after irradiation, the The decline in 1 cow was remarkable, and polypropylene,
The embrittlement of the 1s1 fat is promoted and brittle bag breakage also occurs.

In order to prevent the deterioration of the quality of polypropylene 8F due to radiation exposure, there is a method of adding a specific stabilizer to polypropylene clothing. For example, triarylphosphite alone, a combination of triarylphosphite and a hindered phenol antioxidant dz agent, a combination of triarylphosphite and a hindered amine-based surface stabilizer, etc. (Japanese Patent Publication No. 57-179234). .

However, tris-(2,5-di-t-butylphenyl)
-Addition of only phosphite or Hatris-(2,4-di-t-butylphenyl)-phosphite todriarylphosphite results in radiation irradiation stability FJ of -4 for polypropylene resin moldings. be.

For this reason, it is desirable to use other stabilizers, such as 2,6-not-butyl-1)-methylphenol, tetrakis[methylene-31,5-di-1-butyl- When used in combination with a hindered phenolic antioxidant such as 4-hydroxyphenyl)phlopione-1.]methane, it is sufficient to maintain the stability of polypropylene resin moldings immediately after radiation and after irradiation and when subjected to thermal history. If a certain amount is used, yellowing of the molded product becomes a problem.

Also, bis(2,2,'6,6-titramethyl-4-piperidyl)sebachite or dimethylsuccinate 2
- (4-Hydroxy-2,2,6,6-titramethyl-1-piperidyl) When used in combination with a hindered amine-based 11 light and abrasive stabilizer such as ethanol condensate, the radiation stability of polypropylene resin moldings is considerably affected. It is easy to use and does not cause yellowing problems.

Medium f motris-(2,4-di-1-butylphenyl)-
The combination of phosphite and dimethylsaccine=1・-2-(4-hydroxo-2,2,6,6-titramethyl-1-piperidyl) ethanol condensate showed good radiation resistance in 71 cases, and their stability Since these agents are safe, these (
The +-.f7f7 fatty composition is excellent for use in food containers and medical instruments.

However, polypropylene resin molded products containing these stabilizers have good radiation resistance, but
There is almost no transparency, and when this molded product is used as a food or medical container or syringe to contain goods or medicines, the transparency is extremely insufficient, and if it gets mixed into the contents, It has 11 major drawbacks: it is difficult to check for loose dirt and foreign matter, and it is also impossible to check the accurate color tone of the contents.

The present inventors overlapped the sides of several transparent polypropylene resin molded products with excellent radiation resistance, and
4-di-1-butylphenyl)-posphite and/methylsaccine 1-2-(4-hydroxy-2,2,6
, 6-tetramethyl-1-piperidyl) ethanol condensate, para-[-butylbenzoic acid aluminum salt, sebacic acid,
Alternatively, when we attempted to improve the transparency by adding various crystal nucleating agents such as norbitol derivatives, we found that
It has been found that the addition of 4-unit Q-portion significantly improves the transparency of polypropylene molded products, and also maintains sufficient redirection radiation properties.

However, although the radiation resistance of the above composition is significantly superior compared to the effect of adding other stabilizers,
After irradiation with radiation, there is a slight decline in impact resistance, especially after irradiation, and for this reason, the reality is that products that retain their physical properties sufficiently after irradiation with radiation are desired.

As a polypropylene resin having a high single-sided impact property, there is a propylene-ethylene broth copolymer, but this lacks transparency and the contents cannot be seen through at all. Moreover, even if a crystal nucleating agent such as the above-mentioned sorbitol derivative is added to this product, the transparency does not improve at all, and even if other above-mentioned stabilizers are added to give four radiation irradiation properties, the food container, It is not practical for 1fi applications since it requires transparent viewing of the contents of medical instruments and the like.

There is also a method of blending ethylene-propylene rubber with polypropylene resin to increase impact resistance, but this also lacks transparency significantly, and even if a crystal nucleating agent is added to this material, the transparency cannot be improved. "It's too bad for practical use.

The present inventors have discovered a polypropylene resin composition that has even better transparency, radiation resistance, and no deterioration in fm''P resistance.
- By blending a butene copolymer, it is possible to increase the impact strength without impairing the transparency of polypropylene resin. None-1-
By adding 2-(4-hydroxy 2.2.6.6-titramethyl-1-piperidyl) ethanol condensate in combination, it is possible to improve the physical properties immediately after radiation irradiation with excellent transparency and when heat history is added after irradiation. It has been discovered that it is possible to obtain a composition in which the reduction, especially the reduction in impact I, is significantly improved, and the present invention has been completed.

That is, the present invention further provides a composition comprising 100 parts by weight of polypropylene barrel fat and 05 to 50 parts by weight of an ethylene-1 to butene copolymer, and a compound of the general formula 1 (R is a hydrogen atom or a carbon atom number of 1 to 18 sorbitol derivatives represented by o, o i~4-rJ 耽BE, j lis(2,4-di-t-butylphenyl)bosphite o
o1-4 D4 opening, and dimethyl succinate 2
-(4-hydroxy-2,2,6,6-tetramethyl-
This is a polypropylene resin composition characterized by containing 1 to 4 parts by weight of a 1-piperidyl) ethanol condensate, and having good stability against sheet cross-line inspection and excellent transparency.

The polypropylene 4frl 1lfi used in the present invention may be any one of propylene/pomopolymer, propylene-ethylene copolymer, flobylene/-α-olefin copolymer, etc., or a mixture thereof.

The ethylene-1-butene copolymer used in the present invention has an ethylene content of 70 to 97 mol, preferably 85 to 95%.
le%, density 130.82~0.95? / cnf preferably 0.86-092 g/atl ethylene-1-
It is a butene copolymer. The amount of ethylene-1-butene copolymer used is 0.5 mm per 100 mm parts of polypropylene resin.
~50 parts by weight, preferably 1 to 50 parts by weight. 05
Addition of less than the overlapping part will hardly improve the impact strength of the C-molded product, and addition of more than 5 o's weight will result in a decrease in the rigidity of the molded product, and it will also be economically expensive. cause problems.

The norbitol derivative used in the present invention is represented by the following general formula (1), and specifically, R is hydrogen, methyl, ethyl, propinopebutyl, lauryl,
Examples include stearyl groups. Its addition υ[''frost is 0 for the polypropylene side 1111″100 m hi part
01 to 4 car anus, preferably 0.02 to 2-layered part, and addition of Ct to 0.011 part has almost no effect on the transparency of the molded product. Also, even if it is cooled beyond the 4-way part, the effect will not be increased to 11 or 1, or the mold ＼ will protrude heavily during molding, causing trouble. .

In addition, in the present invention, tris(2,4-di-t-butylphenyl)phosphite] and dimethylsuccinate 2-(4-hydrogine-2,2,6,6-tetramethyl-1-piperidyl)ethanol Addition of condensates is also essential.

The amount of tris(2,4-di-t-butylphenyl)phosphite 1- added is 0.01 to 4 parts, preferably 0.01 to 4 parts, preferably 0.02 to 2 parts by weight, per 100 parts by weight of the polypropylene resin. Adding a small amount of 001 parts by weight has no significant effect on the stability after radiation irradiation, and even if more than 4 parts by weight is added, the effect is almost the same as that of 41 parts by weight. Economically, high prices and problems arise.

dimethyltuccine)2-(4-hydroxy2゜2,6
．． Addition of ethanol condensate (6-titrameglue (1-piperidyl)) l'i'i: o, o i to 4 ridges, preferably 0.02
~ Double, the addition of 3,001 nail liver part, which is an acid part, has no significant effect on the stability after radiation irradiation, and even if it is added beyond 4 Ichikawa part, the effect is 4 Ri. It is almost the same as the lower part, but it is economically expensive and causes problems.

Ethylene-1-buteno copolymer, sorbitol derivative represented by general formula (1), tris(2,4-di-t-
The effect of the present invention becomes remarkable by the combined use of bosphite (butylphenyl) and dimethylsac7nate 2-(4-hydroxy 2.2.6°6-tetramethyl-1-piperidyl)ethanol condensate.

That is, using only ethylene-1-butene copolymer, norbitol derivative represented by general formula [1], tris (2,4-7-1-butylphenyl) phosphite,
and zomethylsuccine)2-(4-hydroxy2.2
．． When the 6.6-titramethyl-1-piperidyl) ethanol condensate is not used, the physical properties after radiation irradiation deteriorate significantly, yellowing occurs, and transparency is poor.

Using an ethylene-1-buteno copolymer and a sorbitol derivative represented by the general formula [1],
When not using di-t-butylphenyl) bosphite and dimethyl sac7ate 2-(4-hydroxy 2.2.6.6-tetramethyl-1-piperidyl) ethanol condensate, transparency is excellent, but radiation After irradiation, the quality of the product decreased significantly and yellowing occurred.

If the sorbitol derivative represented by the general formula [1] is not used, there will be little effect of improving the transparency of the molded article, and one of the objectives, a polypropylene + Oj fat composition with excellent transparency, cannot be obtained.

Ethylene-1-butene copolymer, sorbitol derivative represented by general formula (1) and tris(2,4-di-t-
Butylphenyl) phosphitera was used in combination with dimethyl succine) 2-(4-hydroxy 2, 2.6.6-tetramethyl-1-piperidyl) ethanol condensate. inferior to time.

Ethylene-1-buteno copolymer, norbitol derivative represented by general formula [1] and dimethylsuccine-1-2
-(4-hydroxy-2,2,6,6-tetramethyl-
Citris (2-piperidyl) ethanol condensate
, 4-di-t-butylphenyl) phosphite is not used, the surface 1 radiation irradiation property is insufficient compared to when the four phosphites are used together, and molding stability during molding becomes a problem.

A lbitol derivative represented by the general formula CI),) I
using a J-su('2.4-cy-1-butylphenyl)phosphite and dimethylsaccine 1-2-(4-hydroxy2.2.6.6-tetramethyl-1-piperinyl)ethanol condensate, When the ethylene-1-butene copolymer is not used, the impact strength becomes insufficient due to a decrease in the strength of the product after radiation.

Other additives such as antioxidants other than those listed above, ultraviolet absorbers other than those listed above, gland absorbers, normal phase agents, peroxides, dispersants, neutralizing agents, etc. may be added to the resin composition of the present invention as necessary. I can do things.

In that case, the antioxidants 1 and 2 that can be used are 2,6-7
-[-Butyl-p-methylphenol, n-octadecyl-(4-hydroxy-3,5-/-1-butylphenyl)propionate, detrakis[methylene-6-
(ro, 5-t-butyl-4-hydroxyphenyl)
[probionate] methane, etc., but these are lauryl-thiopropionate, which turns yellow due to radiation irradiation)
Although it is also possible to use sulfur-based antioxidants such as , dilaurylthiophropione-1, etc., their use is limited due to the problem of hemolytic properties.

As ultraviolet absorbers, 2-hydroxy-4-I]-octoxy-benzophenone, 2-(2-hydroxy-6,
Representative examples include 5-di-1-butyl-phenyl)5-chlorobenzotriazole.

&;l as peroxide: 2,5-dimethyl-2,5-
Bis(1=butyl・(-ogishi)hexano), sheet t-butyl perphthalate-1・, benzoyl peroxide, etc., and by adding them, the melt flow index can be controlled and the moldability can be greatly improved. .

The 117j resin composition of the present invention contains a polypropylene resin, an ethylene-1-butene copolymer, a norbitol visiting conductor represented by the general formula (1), tris(2,4-7-1-butylphenyl) phosphite, /Methyl succinate 2-.
(4-hydroxy2.2.6.6-tetramethyl-1-
(piperidyl) ethanol condensate and calcium histearate, neutralizing agents, other additives, other crystal nucleating agents, antioxidant IE agents, ultraviolet absorbers, peroxides, etc. are mixed uniformly using a Henner mixer or other blender. It can be obtained by melting and pelletizing the dispersion using an extruder.

This 4fi fat-assembly paraboloid has extremely high stability and excellent transparency against radiation exposure (C), and has extremely excellent properties such as no decrease in impact resistance.
Effective for food packaging, medical equipment, and other uses.

The present invention will be explained in detail below with reference to Examples.

Example 1 Propylene-ethylene random copolymer (melt flow index 132/min, ethylene content 3.5 wt
%) 100 parts by weight of powder, 6 parts by weight of ethylene-1-butene copolymer Tafuma~Δ4085'' (open collar, made by Mitsui Petrochemicals (silk)), 1.3.2.4-di(ethylbenzylidene)nlubitol o, [bins, to') s(2,
4-Ct-butylphenyl)phosphite l-0,0
8i negative part, 0.08 parts by weight of dimethyl chlorinate 2-(4-hydroxy 2.2.6.6-tetramethyl-1-piperidyl)ethanol condensate and 0.07 parts by weight of calcium stearate were added and mixed, Pelletization was carried out using a conventional extruder at an extrusion temperature of about 240°C. This pellet was molded using an injection molding machine for 160 m at an injection convergence of approximately 240°C.
It was molded into a mX 80+n+xX 1 ram flat plate.

The obtained flat plate was exposed to 25 M r of r-rays from a cobalt-60 source.
a d irradiation/ξ glue, and 80℃ after radiation irradiation)'i
- 1TIIai+ for those left in an enclosed atmosphere for 2 weeks
Evaluations were made for yenability, transparency, and yellowing.

The impact-resistant deck plate was placed on a pipe with an inner diameter of 50φ, a 1/2 JV core was applied to it, and a load was dropped from the top, and the crack height was expressed as iF energy (Mitsui East). Pressure chemistry method).

Transparency was measured using a commercially available haze meter (
ASTM TJlooro).

Yellowing was evaluated visually. The rating is based on the following.

0: No yellowing was observed; ■: N yellowing; Δ: yellowing; and ×: yellowing.

The results are shown in Table-1.

Example 2 A flat plate was formed in the same manner as in Example 1 except that the amount of ethylene-1-butene copolymer added was increased to 5 parts by weight.

From then on, the same evaluation as F was conducted.

The results are shown in Table-1.

EXAMPLES A flat plate was obtained by molding in the same manner as in Example 1, except that the amount of ethylene-1-butene copolymer added was increased to 8 parts. From then on, the same evaluation as F was conducted.

The results are shown in Table-1.

Example 4 In Example 2, cooling of tris(2,4-di-t-butylphenyl) phosphite &amp; 2
, 6,6-tetramethyl-1-piperidyl) ethanol condensate was added in an amount of 0.02 jlj to obtain a flat plate in the same manner as in Example 2.

From F1 onwards, similar evaluations were conducted.

The results are shown in Table-1.

Example-5 In Example-2, the addition of tris(2,4-di-t-butylphenyl)phosphite] was 0.051=@4
part, dimethyl succinate 2- (4-hydroxy-2
A flat plate was obtained by molding in the same manner as in Example 2, except that the amount of the ethanol condensate (2,6,6-teI.lamythyl-1-piperidyl) added was 0.05 parts by weight.

Thereafter, similar it'F I+lli was performed.

The results are shown in Table-1.

Comparative Example-1 Actually, in bV Example-1, ethylene-1-butene co-i
t coalescence, 1. 2.4-7(ethylbenziritine)norbitol, tris(2,4-7-t-butylphenyl)phosphite, and dimethylzacunne-1.2
-(4-hydroxy2.2.6.6-tetramethyl-1
In place of the (piperidyl) ethanol condensate, 972,701 parts by weight of tetrakis[methylene-6(ro,5-7-t-butyl-4-hydroxyphenyl)propionate] was added. I got a flat plate.

Similar evaluations were made below.

The results are shown in Table-1.

The radiation resistance of this product is inferior to that of the composition of the present invention, and yellowing is severe and transparency is poor.

Comparative Example-2 A flat plate was obtained by molding in the same manner as in Example-1 except that the ethylene-1-butene copolymer was not used.

Similar evaluations were made below.

The results are shown in Table-1.

The radiation resistance of this product is inferior to that of the composition of the present invention.

Comparative Example--In Example-2, 1,3,2.4-/-(ethylbenzuritin)sorbitol, +-1)su(2,4-di-1-butylphenyl)phosphite and dimethylzacunne- )-2-(4-hydroxy2.2.6.6-tetramethyl-1-piperi/l)ethanol condensate,
Tetrakis [methylene-3 (3,5-di-t-butyl-
4-Hydroxyphenyl)propione-1/]Memetsu 0
A flat plate was obtained by molding in the same manner as in Example 1-2 except that 4 parts of 0 weight #i was added.

Similar evaluations were made below.

The results are shown in Table-1.

The i11 blade irradiation property of this product was inferior to that of the composition of the present invention, and the yellowing was severe and the transparency was poor.

Comparative Example 4 In Example 2, tris(2,4-7-t-butylphenyl)phosphite and/methyl succinate 1
-2- (4-Hydroxy2.2.6.6-titramethyl-1-piperi/l) Instead of the ethanol condensate, tetragis [methylene-3 (ro, 5-7-t-methyl-4
-Hydroxyphenyl) methane 1 bio-methane 0
1 car near: The piece to which 1 part was added was molded in the same manner as in Example-2 to obtain a flat plate.

Similar evaluations were made below.

The results are shown in Table-1.

The radiation resistance and batting line irradiation resistance of this composition were inferior to those of the composition of the present invention, and yellowing was severe.

Comparative Example-5 In Example-2, 1.3.2.4-no(ethylbenzylidene)sorbitol was not used, and Example-2
A flat plate was obtained by molding in the same manner as above.

Similar evaluations were made below.

The results are shown in Table-1.

Although radiation irradiation properties are good, transparency is poor.

Comparative Example-6 In Example-2, dimethylsuccine-1・2-(4
-Hydroxy2.2.6.6-titramethyl-1-piperinor) ethanol condensate was not used (Example 2)
Shape in the same manner as above to obtain a flat plate.

Similar evaluations were made below.

The results are shown in Table-1.

The surface 1 radiation irradiation property of this product is inferior to that of the composition of the present invention.

Comparative Example 7 A flat plate was obtained by molding in the same manner as in Example 2, except that tris(2,4-di-butylphenyl)phosphite was not used.

The same evaluation will be carried out below/ζ.

The results are shown in Table-1.

The radiation resistance of this product is inferior to that of the composition of the present invention.

Comparative Example-8 In Example-2, dimethyl succinate 2-(4-
Tetrakis[methylene-3(3,5-di-1-butyl-4-hydroxyphenyl)propionate]methane was used in place of the hydroxy 2.2.6.6-titramethyl-1-piperidyl) ethanol condensate by o, i weight A flat plate was molded in the same manner as in Example 2, except that a flat plate was prepared and evaluated in the same way.

The results are shown in Table-1.

The irradiation properties of this composition were inferior to those of the composition of the present invention, and yellowing was severe.

Comparative Example-9 In Example-2, /methyl succinate 2-(4-
Bis(2,2,6,
6-tetramethyl-4-piperidyl) sebacate 01
A flat plate was obtained by molding in the same manner as Example 2 except that part by weight was added.

Similar evaluations were made below.

The results are shown in Table-1.

The radiation resistance of this product is inferior to that of the composition of the present invention.

Table 1, 192) Additive A Nidris (2,4-di-t-butylphenyl)
Phosphite additive B: dimethyl sacinate 2-(4-hydroxy-2,2,6,6-titramethyl-1-piperiyl) ethanol condensate additive C: +, 3,2,4-di(ethylbenzylidene) )
Sorbitol Additive D: DeI Ragis [methylene-ro-(ro, 5-di-t-butyl-4-hydroxyphenyl)furopionate] Methane Additive E: Bis(2,2,(S, 6-tetramethyl-
4-Piperidyl) Sebacate Additive F Calcium Nistearate Patent Applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1 Polypropylene 4Dj fat 100i parts and ethylene-
A sorbitol derivative represented by the general formula 1 (wherein R represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms) is further added to a composition consisting of 05 to 50 parts by weight of a 1-butene copolymer. oo1~4■ total parts, tris(2,4-di-t-butylphenyl)bosphite 001~4 parts by weight and dimethylsuccinate 2-(4
-Hydroxy-2゜2,6.6-tetramethyl-1-piperidyl) ethanol condensate 001-4 parts by weight, characterized by good stability against radiation irradiation and excellent transparency. Polypropylene oil composition.