JPS6132342B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to polyolefin formulations with excellent process stability and color. Polyolefin molding process is usually over 200℃.
Sometimes it is carried out at temperatures close to 300 degrees Celsius. At this time, these polymers often deteriorate in properties or become colored due to chemical effects such as hot oxygen and mechanical effects such as shearing force, resulting in a significant loss of product value. It is known that it is effective to add vitamin E (tocopherols) from the vitamin E group as a stabilizer to polyolefin in order to prevent quality deterioration during molding.
When blended with polyolefin, the hue of the polyolefin decreases, so an improvement has been desired. In addition, 2,6-di-tert-butyl-P-cresol (hereinafter abbreviated as BHT) has traditionally been used as a stabilizer for polyolefins, but when mixed with vitamin E in polyolefins, it causes yellowing. Until now, such formulations have been avoided because they significantly reduce commercial value.
However, since it is unavoidable to mix vitamin E and BHT compounds when handling these polymers, a vitamin E compound that does not cause yellowing even if BHT is mixed is desired. Ta. The present invention was arrived at as a result of studies to meet these demands, and by using a specific phosphite compound together with a vitamin selected from the vitamin E group, a polyolefin compound with excellent process stability and color can be created. It's hot,
This is based on the discovery of a compound that can prevent yellowing even when BHT is mixed in. That is, the present invention provides polyolefin with vitamins selected from vitamin E and the general formula (In the formula, R ¹ , R ² and R ³ are the same or different alkyl groups having 6 to 30 carbon atoms, and R ⁴ , R ⁵ , R ⁶
and R ⁷ are the same or different organic groups having 1 to 80 carbon atoms selected from alkyl groups, alkenyl groups, aryl groups, aralyl groups, and cycloalkyl groups; It is a functional phenol residue. Here, a, b, and c are integers from 0 to 3, and a+b+c≧2,
d is a positive integer from 1 to 4. The polyolefins used in the present invention include ethylene, propylene, 1-butene, 1-hexene, 4
- Homopolymers or copolymers of two or more a-olefins such as methyl-1-pentene, such as polyethylene, polypropylene, poly-1
-Butene, polyisobutene, poly-3-methyl-
1-butene, poly-4-methyl-1-pentene,
Ethylene-propylene copolymer, ethylene-1-
Examples include butene copolymer, ethylene-4-methyl-1-pentene copolymer, propylene-1-butene copolymer, and 1-decene-4-methyl-1-pentene copolymer. In the case of copolymers, copolymers containing α-olefin and polyunsaturated compounds such as conjugated dienes and non-conjugated dienes, or acrylic acid, methacrylic acid, vinyl acetate, etc., are also included. These polymers may be acid-modified, for example, polymers graft-modified with α/β-unsaturated fatty acids, alicyclic carboxylic acids, or derivatives thereof, and may be rubber-like, resin-like, or wax-like. Contains polymers of The vitamin E group that is blended into these polyolefins includes various tocopherols such as α, β, γ, and δ, mixtures thereof, tocols, and various salts thereof such as hydrochlorides, acetates, and phosphates.
At least one selected from these vitamin E groups
More than one type of vitamin is used. The amount of the vitamin selected from the vitamin E group is 0.005 to 0.5 parts by weight, preferably 0.01 to 0.2 parts by weight, per 100 parts by weight of the polyolefin. The phosphite compound used in combination with a vitamin selected from the vitamin E group has the above general formula []
It is a phosphite compound selected from the compounds represented by [ ] and [ ]. In the compound represented by the general formula [], R ¹ ,
R ² and R ³ each have 6 to 30 carbon atoms, preferably 9 carbon atoms.
These alkyl groups are at least 2 or more, preferably 3 or more. Suitable compounds represented by the general formula [] include tris(nonylphenyl)phosphite,
Tris (mixed mono and di-nonylphenyl)
There is a phosphite. In the compound represented by the general formula [], X represents a polyhydric alcohol residue such as glycerin, 1,6-hexanediol, sorbitol, pentaerythritol, and dipentaerythritol. In the compound represented by the general formula [], Y is a polycyclic polyhydric phenol residue, 4,4'-dihydroxydiphenyl, 2,2'-methylenebis(4-methyl-6
-tert-butylphenol), 4,4-methylenebis(2,6-di-tert-butylphenol),
Bisphenol A, alkylated bisphenol,
1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tris(1-methyl-4-hydroxy-5-tert-butylbenzyl) -1・
Examples include residues such as 1,3-butene. In the general formula, R ⁴ , R ⁵ , R ⁶ and R ⁷ are the same or different organic groups having 1 to 80 carbon atoms selected from alkyl groups, alkenyl groups, aryl groups, aralyl groups, and cycloalkyl groups, particularly A higher alkyl group having 9 or more carbon atoms is preferred. Among the compounds represented by these general formulas, preferred are distearyl pentaerythritol diphosphite and It is. However, + indicates a tert-butyl group. The blending amount of these phosphite compounds is preferably 0.005 to 0.5 parts by weight, particularly 0.01 to 0.2 parts by weight, per 100 parts by weight of the polyolefin.
If the amount is less than 0.005 part by weight, there is almost no thermal stabilizing effect, and if it is added in excess of 0.5 part by weight, there is not much difference in the effect, and other physical properties are deteriorated on the contrary, which is not preferable. The formulation according to the invention may contain:
Other additives, such as process oils, plasticizers, lubricating oils, organic or inorganic fillers, dyes, pigments, nucleating agents, antistatic agents, mold release agents, fungicides, antioxidants, UV absorbers, A refueling agent can be added. When used in combination with other stabilizers, synergistic effects may be observed. Examples of these include the phenolic stabilizer O-tert-butyl-p-
Methoxyphenol (BHA), Tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane (Irganox1010), 4,4'-Butylidenebis(6-
tert-butyl-m-cresol), 1,3,5-
Trimethyl-2,4,6-tris((3,5-di-tert-butyl-4-hydroxybenzyl)benzene, styrenated cresol, and the amine stabilizer N・N'-di-sec-butyl- p-phenylenediamine, 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, phenothiazine, N・N'-diphenyl-p-phenylenediamine, dilaurylthiodipropionate, dimyristylthio Thiodialkanoic acid esters such as dipropionate, ascorbic acid, fatty acid monoglycerides, benzophenone, 2-(2'-hydroxy-3', 5'-di-tert-butylphenyl)-5-
Benzotriazole compounds such as chlorobenzotriazole, 4-benzoyloxy-2.2.
There are piperidine core-containing compounds such as 6,6-tetramethylpiperidine, and piperazine core-containing compounds such as 2,2,6,6-tetramethylpiperazine. Depending on the application, one or more of these compounds may be used in combination, and the amount of each compound is usually 0.01 to 1 part by weight per 100 parts by weight of the polyolefin. Other additives include magnesium oxide,
Magnesium hydroxide, alumina, aluminum hydroxide, silica, hydrotalcite, talc, clay, barium sulfate, gypsum, glass fiber, wood flour, synthetic wood fiber, titania, calcium carbonate,
carbon black, mica, petroleum resin, rosin,
An example is natural rubber. The blending amount of these is 1 to 100 parts by weight of polyolefin.
50 parts by weight is usual. When polyolefin obtained by polymerization using a Ziegler type catalyst is used without deashing, it is more effective to use an alcohol or polyhydric alcohol having an ether bond, ester bond, or amino bond in addition to the above stabilizer. becomes noticeable. Examples of such compounds include:
Polyhydric alcohols such as glycerin, sorbitan, pentaerythritol, partial esters of these polyhydric alcohols and fatty acids having 8 to 22 carbon atoms, polyethylene glycol, polypropylene glycol, citric acid mono- or distearate, propylene glycol, sucrose, polyester Glycerin, polyethylene glycol, polypropylene glycol, polyoxyethylene glycerin,
C8 to C22 fatty acid partial esters of polyhydric alcohols such as polyoxyethylene sorbitan,
Monoether of polyethylene glycol and aliphatic alcohol having 12 to 22 carbon atoms or phenol having an alkyl group having 4 to 22 carbon atoms, aliphatic amine having 8 to 22 carbon atoms or N-N-bis(2) of aliphatic amine; -hydroxyethyl) substituted product. These are preferably added in an amount of 0.01 to 5 parts by weight, particularly preferably 0.05 to 1.0 parts by weight, per 100 parts by weight of the polyolefin. The vitamin E group, phosphite compounds, or other additives may be added to the polyolefin by any method suitable for obtaining a homogeneous composition. That is, vitamin E
The compound, phosphite compound, and other additives may be blended together or individually, or some or all of these components may be mixed as a masterbatch. Examples of blending methods include dissolving or dispersing these additives in a low boiling point solvent, mixing this with polyolefin powder, and then removing the solvent by volatilization; There is a method of adding and mixing additives, or a method of using a Banbury mixer, a Henschel mixer, etc. These formulations are preferably carried out under a nitrogen blanket. According to the present invention, polyolefin formulations with excellent process stability and color are obtained. Furthermore, the composition of the present invention does not turn yellow even when BHT is mixed in, so it can be used in a wide range of applications including various molded products and packaging. Examples are shown below. Comparative example 1 Polypropylene (Mitsui Petrochemical Polypropylene)
0.1 part by weight of calcium stearate and 0.03 part by weight of vitamin E (manufactured by Riken Vitamin Oil) were added to 100 parts by weight of powder of B200), and the mixture was molded into pellets using a granulator at a resin temperature of 300°C under a nitrogen atmosphere.
The melt index (MI) of this pellet is
Measured according to ASTM-D-1238-65T. Further, this pellet was preheated at 250°C for 10 minutes and formed into a press sheet (65 mm x 65 mm x 2 mm). Using this press sheet, the whiteness WI (%) and the change in whiteness over time △WI (%) were determined. However, WI and △WI are defined by the following formula, and the value of the light reflectance R (%) in the formula is calculated using a self-recording spectrophotometer (DOUBLE-
40RC, manufactured by Shimadzu Corporation). WI (%) = R ₄₀₀ / R ₇₀₀ × 100 △WI = WI−WI′ (However, R ₇₀₀ is the reflectance (%) at a wavelength of 700 nm,
(The same applies hereafter, and WI' is the value of the press sheet after being left at 80°C and 100% RH for 10 days.) Examples 1 to 6 The same procedure as Comparative Example 1 was carried out except that the following phosphite compounds were additionally blended. Ivy. The results are shown in Table 1. Compound (A) Compound (B) Compound (C) By using the phosphite-based compound of the present invention in combination, the increase in MI of polypropylene is suppressed, and process stability is excellent. Furthermore, since the amount of change in whiteness over time is negative, it is clear that there is no decrease in hue. Comparative Example 2 and Examples 7 to 12 Press sheets were molded in the same manner as in the previous example except that 0.01 part by weight of BHT was added. However, the resin temperature during pellet molding was 240°C. Using this press sheet, yellowness change over time△
YI (%) was calculated. △YI was defined by the following formula. △YI=YI′−YI YI=2R ₇₀₀ −R ₄₅₅ −R _427.5 (In the formula, R ₇₀₀ is the reflectance at a wavelength of 700 nm, the same applies _hereafter , and YI′ is the reflectance after being left at 80°C and 100% RH for 10 days. (This is the value of the press sheet) Due to the contamination of BHT, vitamin E-containing polypropylene shows significant yellowing (Comparative Example 2). However, by using the phosphite compound of the present invention in combination, it became possible to prevent yellowing.

【table】

[Table] Comparative Examples 3 to 5 Triphenylphosphite instead of compound (A)
(a) or distearylthiodipropionate (b) or tetrakis [methylene-3-(3,5-di-
ΔWI and ΔYI were measured in the same manner as in Example 2 or 8, except that tert-butyl-4-hydroxyphenyl)propionate]methane (c) was used. The results are shown in Table 3.

【table】

Claims (1)

[Claims] 1. A polyolefin containing a vitamin selected from the vitamin E group and a general formula (In the formula, R ¹ , R ² and R ³ are the same or different alkyl groups having 6 to 30 carbon atoms, and R ⁴ , R ⁵ , R ⁶
and R ⁷ are the same or different organic groups having 1 to 80 carbon atoms selected from alkyl groups, alkenyl groups, aryl groups, aralyl groups, and cycloalkyl groups; It is a valent phenol residue. Here, a, b, and c are integers from 0 to 3, and a+b+c≧2,
d is a positive integer from 1 to 4) A polyolefin blend characterized by blending a phosphite-based compound selected from the compounds shown below. 2. Claims characterized in that 0.005 to 0.5 parts by weight of a vitamin selected from the vitamin E group and 0.005 to 0.5 parts by weight of a phosphite compound selected from the compounds represented by the above general formula are blended into 100 parts by weight of polyolefin. Polyolefin formulation according to paragraph 1.