JPH07316552A - Method of handling antioxidant - Google Patents

Abstract

PURPOSE: To store or transport a large amt. of an antioxidant in a simple and convenient manner without causing solidification or explosion by storing or transporting a low-m.p. phenolic antioxidant in the molten state in storage equipment having a heating apparatus or with transport equipment having a heating apparatus.

CONSTITUTION: A phenolic antioxidant having an m.p. of 85°C or lower [e.g. octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate] is thermally melted completely with a heating apparatus. The antioxidant in the molten state is stored in storage equipment having a heating apparatus or transported with transport equipment having a heating apparatus.

COPYRIGHT: (C)1995,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for handling an antioxidant, and more specifically, it has a low melting point, is apt to solidify under pressure, and may cause a dust explosion during air transportation. The present invention relates to a handling method for safe, convenient, and low cost storage or mass transportation.

[0002]

2. Description of the Related Art Generally, a chemical factory produces an oxidative effect by a polymerization reaction when producing resins such as polystyrene, acrylonitrile-butadiene-styrene (ABS), polypropylene, adhesives and polyvinyl chloride (PVC). To prevent this, an antioxidant is added to the reaction product to suppress oxidation of the product and promote stability. In the step of producing the resin raw material, phenol-based, phosphorus-based, thioether-based, etc. are often used as antioxidants. Of these, octadecyl-3- (3,5-di-
Tert-Butyl-4-hydroxy-phenyl) -propionate (Ciba Geigy, trade name IRGANOX 107
6, hereinafter abbreviated as IX-1076), triethylene glycol-bis-3- (3-tert-butyl-4-hydroxy-)
5-methylphenyl) -propionate (hereinafter IX-2
(Abbreviated as 45) is a typical example of a commonly used phenolic antioxidant.

However, IX-1076 and IX-2
Antioxidants such as 45 are rather difficult to handle and are a nuisance to ordinary chemical plants. As an example, IX-107
6 has a low melting point and easily solidifies when pressure is applied, so that it melts and solidifies under a slight pressure or temperature (a temperature higher than 45 ° C.). And according to experience,
If only 50kg weight is applied, 25kg package I
X-1076 can be allowed to set in a week. Furthermore, if it is stored in a large storage tank (for example, a storage tank capable of storing 2 tons of IX-1076), IX-1076 forms a lump at the bottom of the storage tank within 4 hours and cannot be taken out. Even if a stirrer is used, this phenomenon cannot be improved. Therefore, it is usually necessary to pack a small amount (for example, 25 kg per pack) of IX-1076, and it is desirable to store two packs in one cardboard box so as not to stack too much. Use a regular PP bag. Cannot be packaged and transported in bulk.

Another problem when dealing with IX-1076 is:
Dust explosion is likely to occur when transported by air transportation means. Usually, as a method of measuring the possibility of dust explosion, a constant electric energy (for example, 10,000 joules) is applied to a sample in a closed storage tank to induce a spark,
There is a method of observing whether or not the sample causes a dust explosion. In addition, VDI Guideline-3673 (1985) set by the German Engineers Association also proposes a test method for dust explosion. The Kst measured by this method indicates the maximum allowable pressure rise in a container of 1 m ³ under test conditions. For example, when 30 g of IX-1076 dust is present in a volume of 1 m ³ , Ks
When t reaches 157 bar · m / sec, dust explosion may occur, so it must be handled carefully. Therefore, when handling a large amount of IX-1076, it is not appropriate to transport by conventional air transportation means.

Conventionally, the maximum storage tank for powder is generally about 2 tons, and it is transported by pressure by air. IX-1076
Due to its characteristics, when stored in such a storage tank, the storage time is limited to 4 hours to avoid hardening. In addition, all containers must use explosion-proof type, so the cost is about 3 ~ compared with general equipment.
It is five times higher, and even if a pressure-proof explosion-proof container is used, there is still the possibility of dust explosion, and it cannot be said that the safety is perfect.

Further, until now, the antioxidant IX-10
The handling of 76 is almost done manually, that is, after storing 2 packs each in a cardboard box, it is stored in a warehouse, and when used, it is transported to the site, and a worker at the site opens the cardboard box as necessary, and IX- 1076 is weighed and charged into the reaction tank manually or by a feeder.
This handling method has the following drawbacks.

1. The cardboard box is bulky and takes up wasted space. 2. There is a possibility of damage or contamination during transportation and handling. 3. Workers are exposed to harmful air due to organic solvents or dust during manual charging. 4. Preparation by feeder is expensive. 5. Cardboard boxes are expensive and consume forest resources. 6. Risk of dust explosion. 7. The cost of manpower is high.

[0008]

In view of the above, the present invention is a method for storing or transporting a large amount of a low melting point antioxidant, which is simpler than the conventional storage method or transport method,
It is an object of the present invention to provide an antioxidant handling method that is low in cost and high in safety.

[0009]

Means for Solving the Problems As a result of intensive studies in view of the above-mentioned various problems, the present inventors have heated an antioxidant into a molten state or dissolved it with a solvent into a solution state. It has been found that the problems of the above-mentioned conventional techniques can be greatly reduced by transporting or storing the same in a container.

That is, according to the present invention, (a) a step of heating a phenolic antioxidant having a melting point of 85 ° C. or lower by a heating device to completely melt it, and (b) the antioxidant in the molten state, Provided is a method of handling an antioxidant, which comprises a step of storing by a storage facility with a heating device or transporting by a transportation facility with a heating device.

Next, the present invention comprises (a) a step of dissolving a phenolic antioxidant having a melting point of 85 ° C. or less in a single solvent or a mixed solvent of two or more kinds, and (b) step (a) Provided is a method for handling an antioxidant, comprising the step of storing the obtained antioxidant solution in a storage facility or transporting it to a transportation facility.

The present invention will be described below with reference to examples of the antioxidant IX-1076. IX-1076, or octadecyl-3- (3,5-di-tert-butyl-4-hydroxy-phenyl) -propionate, as an antioxidant in this example has a structure as shown in the formula below.

[Chemical 1]

From this structural formula, it is clear that IX-1076 is a phenolic compound having steric hindrance. IX-1076 itself has no bad odor, has light stability and good color recovery, has good compatibility with many resins, and has advantages such as low volatility and high extraction resistance. Polyalkylenes such as polyethylene and polypropylene, polystyrene, impact resistant polystyrene, ABS,
MBS, linear polyester, PVC, polyimide, polyurethane, EPR, EPDM and other elastomers, BR,
It can be added to synthetic rubber such as SBR and organic polymer such as adhesive. IX-1076 can effectively prevent these resins from oxidative degradation or crosslinking due to heat.

Despite the advantages of IX-1076 in such properties, as shown above, commercially available powdered IX-1076 tends to harden under pressure, and
Even in the case of pneumatic transportation, there are drawbacks such as a risk of dust explosion, which causes considerable difficulty in packaging, storage and mass transportation. Usually, in the production of a phenolic antioxidant such as IX-1076, after the completion of the reaction, it is refined, and thereafter, it exhibits a lump or a powdery coarse crystalline form having non-uniform particle size and size, and It must be crushed and then sorted. However, according to the method of the present invention,
After IX-1076 can be produced, the crude crystal as it is without crushing or screening can be melt-processed or dissolved by a solvent and then provided to the user in a state of being stored or transported. . Therefore, according to the method of the present invention, IX
The production of -1076 can omit the steps of crushing and sorting, and can significantly reduce the cost.

The present invention provides the following melting method and dissolution method for the method of storing and transporting a low melting point phenolic antioxidant having a melting point of 80 ° C. or lower such as IX-1076.

[Melting Method] IX-1076 has a molecular weight of about 53.
1, a yellowish white crystalline solid with a melting point of 49-54 ° C. Depending on the characteristics of this low melting point, a commonly used heating device, for example, a heating barrel or heating tank, a heat exchanger, a heating coil, etc.,
By heating by supplying hot water, steam, heating oil or electric energy, it is melted at a temperature of 50 to 60 ° C. Then, the molten state IX-1076
Pump to storage tanks or transport vehicles, and also
In order to prevent IX-1076 from degrading, the reservoir or vehicle is further filled with an inert gas, thereby isolating oxygen and moisture from IX-1076. In addition, since the transport vehicle and the storage tank are equipped with a heating device, IX-1
076 holds a molten state in the range of 50 to 60 ° C., and can be further charged into a reaction tank by a pump.

Regarding the stability of IX-1076 in the molten state, as is apparent from Table 1 below, even when it was stored at 70 ° C. for 30 days in a nitrogen atmosphere, its appearance was still transparent and colorless, and Even if it is dissolved in toluene to a concentration of 5% by weight and its transmittance is measured by ultraviolet rays having a wavelength of 425 nm, there is little change. On the other hand, when stored at 70 ° C. in the atmosphere, IX-1076 oxidizes and becomes slightly yellow after 48 hours or more. In short, when IX-1076 is stored in a nitrogen atmosphere, its stability is extremely high.

[0018]

[Table 1]

[Solution Method] Table 2 shows I for various organic solvents.
The solubility of X-1076 is shown. As is clear from this table, IX-1076 can be dissolved in various organic solvents. Further, from the fact that the solubility of IX-1076 in styrene reaches 40 to 60 g / 100 g styrene, IX-1076 is very easily soluble in styrene monomer. On the other hand, the styrene monomer is a raw material for producing polymers such as polystyrene, impact-resistant polystyrene, ABS and SBR, and IX-1076 is
It is an antioxidant that is often used to prevent oxidative deterioration or crosslinking due to heat when producing a resin raw material by polymerization or when using a polymer product. Therefore, in the manufacturing process of polystyrene, ABS, SBR, etc., IX-1076 is dissolved in styrene monomer in advance, and a monomer solution containing an antioxidant is added to the reaction system to have an antioxidant effect. Polymer products can be manufactured.

[0020]

[Table 2]

The following method can be used to dissolve IX-1076 in the styrene monomer. For example,
IX-1076 crude crystals are added to the styrene monomer and then stirred with a stirrer. According to an experiment, it took about 70 seconds to completely dissolve 45 g of IX-1076 in 100 g of styrene monomer at 25 ° C., and 20 g of IX-1076 was mixed with 100 g of styrene monomer at 0 ° C. Approximately 90 seconds were required to completely dissolve it in. Further, if IX-1076 is added to the styrene monomer placed on the transportation vehicle and transported as it is, the stirring effect can be similarly obtained by vibration during traveling. Regarding the advantages of the melting method, transportation equipment such as transportation vehicles and transportation pipes do not require heating equipment and heat insulation equipment like the melting method, and storage tanks and transportation vehicles also need to be sealed with nitrogen. It is not limited but can be raised.

The solvent used in the dissolution method in the present invention includes the reaction components themselves in the reaction system, or a single solvent or a mixed solvent of two or more components that does not interfere with the reaction. The solubility is preferably 5 g / 100 g solvent or more, and more preferably 10 g / 100 g solvent or more. Examples of the solvent applied to IX-1076 include styrene, methyl methacrylate, acrylonitrile, ethylbenzene, hexane (pure n-hexane or a mixture thereof), cyclohexane (pure n-cyclohexane or a mixture thereof), benzene, ethyl acetate, toluene, chloroform. , Xylene, dodecane, octane,
Kerosene, cyclohexanone, and mixtures thereof. IX-1076 has a solubility of 5 g / 100 g or more in any of the above solvents.

Regarding the stability of the antioxidant solution, IX-
Taking an example of a solution prepared by dissolving 1076 in a styrene monomer, as is clear from Table 3 below, the solution stored at 40 ° C. in the air in a nitrogen atmosphere for 6 hours has a slightly yellowish hue. And the UV transmittance drops slightly, but 6
There is only a slight change in the UV transmittance over time. In this respect, the reaction mechanism is not known, but as is apparent from the application example, the storage period at 40 ° C. in the air for 12 days and the storage in a nitrogen-containing atmosphere for 0 hours, 6 hours, 12 days, etc. are different. The products obtained by placing the solutions for a certain period in reaction vessels under the same reaction conditions to produce impact resistant polystyrene have almost the same physical properties and hues.

[0024]

[Table 3]

The procedure of the two methods of the present invention will be described with reference to FIG. As shown, the transport vehicle 1 transports the melted antioxidant or mixture of solvent and antioxidant. When the melting method is used, the transportation vehicle 1 needs to be provided with a heating device. When the dissolution method is used, the transportation vehicle 1 does not need to be provided with a heating device, but after the mixture of the solvent and the antioxidant is stirred and completely dissolved in advance, it is sent to the transportation vehicle 1 by a pump, or The mixture is charged and mixed as it is into the transportation vehicle 1 without stirring, and the antioxidant is dissolved in the solvent by vibration during traveling.

The molten antioxidant or antioxidant solution is transported by the transport vehicle 1 to the next factory, and then pumped to the storage tank 3 for storage. When using the melting method,
In order to keep the antioxidant in the molten state, the storage tank 3 must be fitted with a heating device. When the dissolution method is used, it is not necessary to provide the storage tank 3 with a heating device. At the time of use, the pump 4 may send the molten antioxidant or antioxidant solution to the feeder 5.

The antioxidants that can be transported or stored by the method of the present invention include, in addition to IX-1076, many antioxidants shown in Table 4 below.

[0028]

[Table 4]

Among these antioxidants, IX-245
Is applied to various polymers, and is particularly preferable for styrene-based polymers such as impact-resistant polystyrene and ABS resin,
It is also effective in improving the stability of polymers such as polyurethane, polyamide, thermoplastic polyester and PVC, and can effectively prevent oxidative deterioration due to heat in the production, processing and use of the polymer. it can. IX-2
45 is a slightly yellowish white crystal, and its melting point is in the range of 76 to 79 ° C., so that it may be applied to the melting method of the present invention, and as is clear from Table 5 below. ,
Since the solubility in various solvents is good, the dissolution method of the present invention can also be applied.

[0030]

[Table 5]

BHT has no fear of environmental pollution, and
It is an antioxidant with excellent heat resistance and durability, and has a white crystalline body with a melting point of 69 to 74 ° C. BHT is particularly applied to products such as synthetic rubber, synthetic resins such as polyethylene, paints and oils. Examples of the solubility of BHT in organic solvents are shown in Table 6 below.

[0032]

[Table 6]

Since the light yellow crystalline powder of IX-1035 has a melting point in the range of 63 to 68 ° C., the handling method of the present invention can also be applied.

[Application Examples] The following are IX-107 of different storage conditions added to the polymerization reaction of impact-resistant polystyrene.
6 is shown. No. IX-1076 Handling method Storage conditions a Powdery (commercially available) -b Melting method 70 ° C, N ₂ , 15 days c Melting method 40 ° C, N ₂ , 0 hours d Melting method 40 ° C, N ₂ , 6 hours e Dissolution method 40 ° C, N ₂ , 12 days f Dissolution method 40 ° C, air, 12 days

The volume of the reaction vessel was 300 liters, the charging flow rate was 41 liters / hr, and the composition was as follows. Ingredients containing organic weight styrene 83 parts by weight Ethylbenzene 10 parts by weight of polybutadiene rubber 6 parts by IX-1076 0.15 part by weight of mineral oil 0.5 parts by weight polymerization initiator (trigonox D-E50) 0.02 part by weight herein Trigonox D-E50 is 2,2-di-
Represents (tert-butyl peroxide) butane.

Polymerization was carried out by setting the reaction temperature in the range of 100 to 220 ° C., and after the conversion of the monomers reached 80% by weight, the polymer solution was charged into a degassing volatilization tank to remove volatile components. It is removed and then extruded by an extruder to obtain pellets. Table 7 below shows the results of measuring the physical properties of resin products obtained by injection molding of the pellets.

[0037]

[Table 7]

In Table 7, MI represents fluidity, and AST
It was measured by the method of MD-1238. Izod represents Izod impact strength and was measured by the method of ASTM D-256. TS _Y represents tensile strength, ASTM
It was measured by the method of D-638. YI represents yellowness and was measured by the method of ASTM D-1925.

[Brief description of drawings]

1 is a schematic diagram showing the procedure of the method of the present invention.

[Procedure amendment]

[Submission date] June 17, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art Generally, chemical plants produce a resin such as polystyrene, acrylonitrile-butadiene-styrene (ABS), polypropylene, adhesive, and polyvinyl chloride (PVC), which undergoes a polymerization reaction and subsequent oxidation. In order to suppress the generation, an antioxidant is added to the reaction product to suppress the oxidation of the product and promote stability. In the step of producing the resin raw material, phenol-based, phosphorus-based, thioether-based, etc. are often used as antioxidants. Of these, octadecyl-3- (3,5-
Di-tert-butyl-4-hydroxy-phenyl) -propionate (Ciba Geigy, trade name IRGANOX 10
76, hereinafter abbreviated as IX-1076), triethylene glycol-bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) -propionate (hereinafter IX-).
245) is a typical example of a commonly used phenolic antioxidant.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

The solvent used in the dissolution method in the present invention includes the reaction components themselves in the reaction system, or a single solvent or a mixed solvent of two or more components that does not interfere with the reaction. The solubility is preferably 5 g / 100 g solvent or more, and more preferably 10 g / 100 g solvent or more. As the solvent to be applied to the IX-1076, styrene, methyl methacrylate, acrylonitrile, ethyl benzene, hexane, cyclohexane (pure n- cyclohexane or mixtures thereof), benzene, ethyl acetate, toluene, chloroform, xylene,
Dodecane, octane, kerosene, cyclohexanone, and mixtures thereof. IX-1076 has a solubility of 5 g / 100 g or more in any of the above solvents.

Claims (7)

[Claims] 1. A process of (a) heating a phenolic antioxidant having a melting point of 85 ° C. or less by a heating device to completely melt it, and (b) storing the antioxidant in a molten state with a heating device. A method of handling an antioxidant, comprising the step of storing in an equipment or transporting by a transportation facility with a heating device. 2. The method for handling an antioxidant according to claim 1, wherein the step (b) is performed in an inert gas atmosphere. 3. The antioxidant is octadecyl-3-
(3,5-Di-tert-butyl-4-hydroxy-phenyl) -propionate, triethylene glycol-bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) -propionate, 2,2 -Thio-diethylene-bis- [3- (3,5-di-tert-butyl-4-hydroxy) phenyl] propionate, and 2,6-di-tert-butyl-methylphenol The method for handling an antioxidant according to claim 1, which is at least one compound. 4. (a) a step of dissolving a phenolic antioxidant having a melting point of 85 ° C. or lower in a single solvent or a mixed solvent of two or more kinds, and (b) the antioxidant obtained in step (a) A method for handling an antioxidant, comprising the step of storing the agent solution in a storage facility or transporting it by a transportation facility. 5. Handling of the antioxidant according to claim 4, wherein a solvent capable of dissolving 5 g or more of the phenolic antioxidant in 100 g of the solvent at 20 ° C. is used in the step (a). Method. 6. The method for handling an antioxidant according to claim 4, wherein the solvent is styrene. 7. The antioxidant is octadecyl-3-
(3,5-Di-tert-butyl-4-hydroxy-phenyl) -propionate, triethylene glycol-bis-3 (3-tert-butyl-4-hydroxy-5-methylphenyl) -propionate, 2,2- Thio-diethylene-bis- [3- (3,5-di-tert-butyl-4-hydroxy) phenyl] propionate, and 2,6-di-
The method for handling an antioxidant according to claim 4, wherein the antioxidant is at least one compound selected from the group consisting of tert-butyl-methylphenol.