JPS6210542B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a stabilized synthetic resin composition, and more particularly to a synthetic resin composition with improved long-term thermal oxidative stability and thermal colorability, which is formulated with a non-toxic natural antioxidant. polyethylene, polypropylene, ABS resin,
Synthetic resins such as polyvinyl chloride resin and rubber are susceptible to heat,
It is known that it deteriorates due to the effects of air and light, becoming discolored and decreasing in mechanical strength, making it unusable. In order to prevent such deterioration of synthetic resins, many additives have been used singly or in various combinations. Among these additives, phenolic antioxidants have a relatively large stabilizing effect and are used as main stabilizers. However, recently, the safety of certain types of these phenolic compounds to the human body has been brought into question.
In particular, these resins are used in food packaging containers, tableware, toys,
Toxicity when used in medical devices has become a major social problem. Therefore, there is a demand for the development of safer stabilizers, and tocopherols and other vitamins have been proposed as such non-toxic stabilizers. However, when these vitamins are used alone, their stabilizing effect is not sufficient, and it is necessary to use them in combination with various compensating agents. In addition, when these vitamins exert their stabilizing effects, such as tocopherols,
In many cases, molded products are colored by forming chromophores called tocoquinone or tocolets, and it is also necessary to use additives that have coloration prevention ability. As a result of intensive studies in view of the current situation, the present inventors have discovered that phytic acid or a metal salt of phytic acid is an excellent compound that can solve all of the above problems, and have arrived at the present invention. Phytic acid or phytic acid metal salts are abundantly contained in plants, especially seeds and shellfish, and are compounds that pose no toxicity problems, and their structure is said to be myo-inositol hexaphosphate. Phytic acid or phytic acid metal salts are known to be used as a heavy metal remover from brandy, wine, etc., as an antioxidant for oils and fats, and as a paint additive, but they are not known to be used as a stabilizer for synthetic resins. . Furthermore, the inventor's tests have revealed that when added alone to a synthetic resin, it has almost no effect. However, although the mechanism of action is still not clear, when phytic acid or phytic acid metal salts are used together with certain vitamins, the two act mutually and improve the thermal oxidative stability of synthetic resins. It has become clear that this has been dramatically improved, that coloring can be prevented to a satisfactory degree, and that the processability of synthetic resins can also be improved. That is, the present invention adds vitamin B group and E to the synthetic resin.
The object of the present invention is to provide a stabilized non-toxic synthetic resin composition containing at least one kind of vitamins selected from the group A and K and at least one kind of phytic acid or a metal salt of phytic acid. The present invention will be explained in more detail below. Examples of the vitamins used in the present invention include vitamin E group (tocopherols selected from various tocopherols α, β, γ, δ and mixtures thereof and dimers thereof), vitamin K ₁ and its acetate, etc. Vitamins selected from derivatives such as vitamin K ₁ , vitamin K ₂ and its acetate esters
Vitamins selected from K ₂ , vitamin K ₃ and their derivatives such as sodium bisulfite adducts
K ₃ types, vitamin K ₄ types selected from vitamin K ₄ and its derivatives such as acetic acid, phosphoric acid, sulfate ester, alkali metal, alkaline earth metal salts, vitamin K ₅ and its hydrochloride, alkali metal salt, alkaline earth metal salt. Vitamin K ₅ selected from derivatives such as similar metal salts, vitamin K ₆ selected from vitamin K 6 and derivatives _such as its monohydrochloride and dihydrochloride
vitamin K ₇ and its derivatives such as its hydrochloride, alkali metal salt, and alkaline earth metal salt Vitamin K ₇ selected from vitamin K ₇ and its derivatives such as its hydrochloride and nitrate
There are vitamin B ₁ types, vitamin B ₂ types selected from vitamin B ₂ and its hydrochlorides and phosphate esters, and vitamin B ₆ types selected from vitamin B ₆ and its hydrochlorides and phosphate esters. Among these, those that exhibit particularly excellent stabilizing effects include DL-α-tocopherol, tocopherol dimer, vitamin _B1 , vitamin E, and vitamin B1.
_K5 class is mentioned. These vitamins are exceptional in that they are almost non-toxic. The amount of these vitamins added is per 100 parts by weight of synthetic resin.
The amount is 0.001 to 5 parts by weight, preferably 0.01 to 3 parts by weight. In addition, metals constituting phytic acid metal salts include sodium, potassium, lithium, calcium, magnesium, strontium, barium,
zinc, nickel, aluminum, zirconium,
Examples include tin, titanium, and antimony. The amount of phytic acid or phytic acid metal salt added depends on the synthetic resin.
0.001 to 5 parts by weight per 100 parts by weight, preferably 0.01
~3 parts by weight. A sulfur-based antioxidant is added to a synthetic resin in the composition of the present invention.
It can also be contained in an amount of 0.001 to 5 parts by weight per 100 parts by weight. Examples of sulfur-based antioxidants include dialkylthiopropionates such as distearylthiodipropionate and dilaurylthiodipropionate, and pentaerythritol tetra(alkylthiopropionate) such as pentaerythritoltetra(laurylthiopropionate). ) can be given. The composition of the present invention may further contain 0.001 to 5 parts by weight of a phenolic antioxidant based on 100 parts by weight of the resin. Examples of phenolic antioxidants include 2,6-di-tert-butyl-p-
Cresol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-methylenebis(2,6-di-tert-butylphenol),
2,2'-methylenebis[6-(1-methylcyclohexyl)p-cresol], 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 2,2'-methylenebis(4-methyl- 6-
nonylphenol), 4,4'-isopropylidene bis(2,6-di-tert-butylphenol),
4,4'-butylidene bis(2,6-di-tert-butylphenol), 4,4'-butylidene bis(6-
tertiary-butyl-m-cresol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 2,6-bis(2-hydroxy-3-nonyl-5-methyl benzyl)-4
-Methylphenol, stearyl-β-(4-hydroxy-3,5-di-tert-butylphenyl)propionate, 1,3,5-tris [(3,5-
di-tert-butyl-4-hydroxyphenyl)propionyloxyethyl]isocyanurate, bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithiol terephthalate, tetrakis[methylene-3-(3. 5-di-tert-butyl-4-hydroxyphenyl)propionate] methane, 1,3,5-tris(3,5-di-
tert-butyl-4-hydroxybenzyl)-2.
4,6-trimethylbenzene, distearyl (4
-Hydroxy-3-methyl-5-tert-butyl)benzyl malonate, 1,3,5-tris(3,5
-di-tert-butyl-4-hydroxybenzyl) isocyanurate, stearyl (3,5-di-methyl-4-hydroxybenzyl) thioglycolate, bis[3,5-bis(4-hydroxy-3-
tertiary-butylphenyl)butyric acid] glycol ester, 2-octylthio-4,6-di(4-hydroxy-3,5-di-tert-butyl)phenoxy-1,3,5-triazine, 4,4'-thiobis( 6-tert-butyl-m-cresol),
1,3,5-tris(2,6-di-methyl-3-
Examples include hydroxy-4-tert-butylbenzyl) isocyanurate. If a light stabilizer is added to the composition of the invention,
Since they can improve photostability, they can be appropriately selected and used depending on the purpose of use. These include benzophenone, benzotriazole, salicylate, substituted acrylonitrile, piperidine, various metal salts or metal chelates, especially nickel or chromium salts or chelates, triazine, and the like. Other materials may be added as necessary, such as pigments, fillers, foaming agents, antistatic agents, metal soaps, organic phosphites, rust preventive agents, plate-out inhibitors, surface treatment agents, lubricants, flame retardants, fluorescent agents, and anti-mold agents. agents, bactericides, metal deactivators, photodegradants, infrared absorbers, processing aids, mold release agents, reinforcing agents, and the like. Examples of the synthetic resins stabilized by the present invention include α-
Olefin polymers or polyolefins such as ethylene-vinyl acetate copolymer and ethylene-propylene copolymer, and their copolymers, polyvinyl chloride, polyvinyl bromide, polyvinyl fluoride, polyvinylidene chloride, chlorinated polyethylene, chlorine polypropylene, polyvinylidene fluoride, brominated polyethylene, chlorinated rubber, vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer,
Vinyl chloride-propylene copolymer, vinyl chloride-
Styrene copolymer, vinyl chloride-isobutylene copolymer, vinyl chloride-vinylidene chloride copolymer,
Vinyl chloride-styrene-maleic anhydride terpolymer, vinyl chloride-styrene-acrylonitrile copolymer, vinyl chloride-butadiene copolymer, vinyl chloride-isoprene copolymer, vinyl chloride-chlorinated propylene copolymer, Vinyl chloride-vinylidene chloride-vinyl acetate terpolymer, vinyl chloride-
Acrylic acid ester copolymers, vinyl chloride-maleic ester copolymers, vinyl chloride-methacrylic ester copolymers, vinyl chloride-acrylonitrile copolymers, halogen-containing synthetic resins such as internally plasticized polyvinyl chloride, polystyrene, Polyvinyl acetate, acrylic resins, copolymers of styrene and other monomers (e.g. maleic anhydride, butadiene, acrylonitrile, etc.), acrylonitrile-butadiene-styrene copolymers, acrylic ester-butadiene-styrene copolymers , methacrylate resin such as methacrylic acid ester-butadiene-styrene copolymer, polymethyl methacrylate, polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, linear polyester, polyamide, polycarbonate, polyacetal, polyurethane, polyphenyl oxide, cellulose resin, Alternatively, phenolic resins, urea resins, melamine resins, epoxy resins, unsaturated polyester resins, silicone resins, etc. can be mentioned. Furthermore, rubbers such as natural rubber, isoprene rubber, butadiene rubber, acrylonitrile-butadiene copolymer rubber, and styrene-butadiene copolymer rubber may be blends of these resins. Also included are crosslinked synthetic resins such as crosslinked polyethylene crosslinked with peroxide or radiation, and foamed synthetic resins such as foamed polystyrene foamed with a foaming agent. The following examples illustrate the effects of the composition according to the present invention, but the present invention is not limited by these examples. Example 1 The following composition was kneaded with a mixing roll at 180°C for 5 minutes, and then compression molded at 180°C and 250 kg/cm ² for 5 minutes to prepare a test piece with a thickness of 1 mm. Using this test piece, a thermal stability test was conducted in a gear oven at 160°C. Further, the yellowness of the test piece after irradiation with a fluorescent lamp for 72 hours was measured using a Hunter colorimeter. The results are shown in Table-1. Unstabilized polypropylene 100 parts by weight Calcium stearate 0.2 Dilaurylthiopropionate 0.2 Vitamin E ^* 0.1 Phosphorus-containing compounds (Table 1) 0.1 * α, β, γ, δ mixed tocopherols, in the following examples same as

【table】

[Table] Example 2 In order to examine the melt viscosity stability of the composition of the present invention, extrusion processing was repeated and the melt viscosity (MFI) was measured. After mixing the following composition in a mixer for 5 minutes, a compound was prepared using an extruder (diameter 50 mm) (cylinder temperature 230°C, 240°C, head die temperature 250°C, rotation speed 20 rpm). Extrude once, 3
The melt viscosity ratios (MFI(3)/MFI(1) and MFI(5)/MFI(1)) of the compound extruded once and the compounds extruded 3 times and 5 times were determined. The results are shown in Table-2. Unstabilized polypropylene 100 parts by weight Calcium stearate 0.15 Pentaerythritol tetra (lauryl thiopropionate) 0.2 Phytic acid, 5Ca, Mg 0.1 Vitamins (Table 2)

【table】

[Table] Example 3 A sheet was prepared using the following formulation, and a thermal stability test at 190°C and an initial colorability test were conducted. A weather resistance test using a weatherometer was also conducted.
Initial coloration indicates yellowness (%) by Hunter colorimeter. The results are shown in Table-3. Compounded PVC (Pinica 37H) 100 parts by weight Dioctyl phthalate 45 Tricresyl phosphate 5 Bisphenol A diglycidyl ether 3 Vitamin E 0.3 Zn-stearate 0.8 Ba-stearate 0.4 Ba-nonyl phenolate 0.5 Sorbitan monopalmitate 1.0 Phosphorus-containing compounds (Table-3) 0.5

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[Table] Example 4 The following formulation was kneaded with a mixing roll at a temperature of 150°C for 5 minutes, and then kneaded at a temperature of 150°C with 180 kg/
Compression molded for 5 minutes at cm ² to a thickness of 1.2 mm.
A sheet was created. This sheet was used as a 10 x 20 mm test piece and subjected to a gear oven heating deterioration test in air at a temperature of 150°C on aluminum foil.
Note that 10 specimens were used for the same sample, and the time when 5 or more specimens became discolored or waxy was defined as the deterioration time. The results are shown in Table 4. Compounded polyethylene resin (HIZEX 5100E, manufactured by Mitsui Oil Co., Ltd.) 100 parts by weight Dilauryl thiodipropionate 0.3 DL-α-tocopherol 0.1 Phosphorus-containing compounds (Table 4) 0.05

[Table] Example 5 In order to see the effect of the stabilizer of the present invention on polybutene resin, the stabilizer of the present invention was tested at a temperature of 140°C with the following formulation.
Knead on a mixing roll for minutes, then 160℃,
Compression molding was performed for 5 minutes at a pressure of 200 kg/cm ² to produce a sheet with a thickness of 1 mm. The obtained sheets were cut into pieces of 40 x 150 mm and hung in separate cylinders to measure the time at which oxidative deterioration began. The results are shown in Table-5. still,
The inside of the cylinder was set at 1 atm in an oxygen atmosphere and at a temperature of 160°C. The start time of oxidative deterioration was determined by reading the time point at which the pressure inside the cylinder began to decrease rapidly using a recorder. Compounded unstabilized polybutene resin 100 parts by weight Calcium stearate 1.0 Distearyl thiodipropionate 0.3 Vitamin E 0.1 Vitamin K _5- hydrochloride 0.1 Phosphorus-containing compounds (Table 5) 0.2

[Table] Example 6 ABS resin (Styrac 200: Asahi Dow)
100 parts by weight TiO 2.0 Calcium stearate 1.0 Phosphorus-containing compounds (Table 6) 0.3 Vitamin K _5- hydrochloride 0.1 The above mixture was extruded at 200°C to form pellets, and the pellets were then in-die extruded at 230°C. A test piece was prepared. The degree of coloration of this test piece after heating in a gear oven at 135°C for 30 hours was expressed as whiteness measured with a Hunter colorimeter. Furthermore, the Izod impact value of the test piece at 20°C was also measured. The results are shown in Table-6.

[Table] Example 7 Polystyrene resin (Denka Polystyrene GP-
1: Denki Kagaku Kogyo) 100 parts by weight Vitamin E 0.05 Phosphorus-containing compound (Table 7) 0.2 The above formulation was injection molded to prepare a test piece with a thickness of 2 mm. After heating this test piece at 120°C for 48 hours, the degree of coloration was measured using a Hunter colorimeter.
Indicated by yellowness. The results are shown in Table-7.

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[Table] Example 8 In order to examine the excellent coloring prevention properties of the rubber-modified polystyrene resin obtained by adding a phosphorus-containing compound during polymerization, polymerization was carried out with the following composition and a performance test was conducted. Synthetic rubber (75 parts butadiene, 25 parts styrene)
7.5 parts by weight Styrene monomer 92.5 Potassium persulfate 0.1 Asymmetric rosin acid sodium 1.0 Dodecyl mercaptan 0.05 Water 200 Phosphorus-containing compound (Table 8) 0.5 After thoroughly stirring water, initiator, and emulsifier, put the synthetic rubber into the polymerization tank. . Subsequently, styrene monomer and phosphorus-containing compound are added. Polymerization is carried out at 70°C for 10 hours, and the resulting polymer is salted out with calcium chloride. Next, it is centrifuged, washed thoroughly with water, and dried at 80°C for 5 hours. 100 parts by weight of the rubber-modified polystyrene resin thus obtained was pulverized, mixed with 1.0 part by weight of calcium stearate and 0.1 part by weight of vitamin E, and pelletized at 200°C using an extruder. This pellet was subjected to in-die extrusion processing at 230°C to prepare a test piece. This test piece was heated in a gear oven at 135℃ for 20 hours.
Whiteness was measured with a Hunter colorimeter. The results are shown in Table-8.

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[Table] Example 9 Styrene-acrylonitrile copolymer resin
100 parts by weight Phytic acid, 5Ca, Mg 0.05 Vitamins (Table 9) 0.05 The above formulation was extruded at 230°C to prepare pellets, and a retention test in an in-die extrusion was conducted at 230°C. No retention, retention after 10 minutes, retention 20
After a few minutes, a test piece with a thickness of 2 mm was injection molded, and the degree of coloration of the test piece was indicated by the degree of yellowness measured with a Hunter colorimeter. The results are shown in Table-9.

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Claims (1)

[Claims] 1. A stabilized non-toxic synthetic resin composition comprising a synthetic resin and at least one vitamin selected from vitamins B, E and K groups and at least one phytic acid or phytic acid metal salt.