JPH0311314B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for modifying hydrophobic organic substances such as carbon black and organic pigments by subjecting them to low temperature gas plasma treatment. It lies in manufacturing. Hydrophobic organic substances such as carbon black and organic pigments have low polarity, so they are difficult to get wet with water and difficult to maintain a dispersed state in water, making it difficult to maintain a stable dispersion state when used in water-based paints and inks. I can't. The present inventors have discovered that so-called channel-type carbon black, which is manufactured through a process in which carbon black is exposed to air at high temperatures for a long period of time, is superior to furnace-type carbon black, which does not require such a process. Focusing on the fact that the wettability to water is relatively high, and this is presumed to be due to the particle surface being oxidized to form surface compounds and increasing the amount of volatile matter, we investigated furnace type carbon black using nitric acid. , Wet oxidation using an oxidizing agent such as sodium hypochlorite, or heating to 250℃ to 300℃ in an electric furnace improves wettability to water and improves dispersibility in water. I succeeded in doing so. [Coloring Materials Association Journal Vol. 45, 637 (1972), Coloring Materials Association Journal,
48, 437 (1975)] However, although oxidation treatments using these methods were effective to some extent, they were not practical for practical purposes due to difficulties in yield, degree of effectiveness, and purification through post-treatment. I couldn't help it. Next, in order to solve these problems all at once, the present inventors invented a method for producing water-dispersible modified carbon black by low-temperature oxygen plasma treatment. (Patent Application No. 046057 of 1981) That is, the surface of carbon black particles is oxidized by low-temperature oxygen plasma treatment, and oxygen-containing acidic surface compounds such as carboxyl groups and phenol groups are formed on the particle surfaces. It is thought that it contributes to water wettability and electrical repulsion, is extremely easy to wet with water, and has excellent dispersibility in water or various aqueous vehicles. In this case, oxygen may be used alone as the oxygen gas, or air may be used as the oxygen source.
Alternatively, it was also possible to use a mixed gas of oxygen, nitrogen, or an inert gas. However, in such low-temperature plasma treatment using oxygen gas or oxygen-containing gas, if the high frequency output is too strong, the ashing of carbon black will be significantly accelerated and the product yield will be extremely poor. Additionally, there was a drawback that the processing effect could not be fully exhibited and the work was forced to be performed at a low efficiency. The present invention improves the drawbacks of the conventional method as described above,
The purpose of this project was to develop a method that would cause almost no ashing even when the high-frequency output was high, resulting in a product yield of approximately 100% and a method that could stably produce high-performance products. This is the completed version. Furthermore, the present invention is not limited to the modification of carbon black, but has also been completed to improve the water dispersibility of hydrophobic organic substances such as organic pigments. Hereinafter, the configuration of the present invention will be explained in detail. The organic pigments used in the present invention include:
Organic pigments commonly used in the paint, ink, plastics industry, etc. are preferred. For example, the azo pigments Irgazin Red LT (manufactured by Ciba), Nova Palm Yellow H10G (manufactured by Hoechst),
Monolight Red BR (manufactured by ICI), azo dye, Sudan, Sudan, Sudan, Sudan (manufactured by Industria Piedmont Colori Dei Anilina), etc. Polycondensed azo pigment Chromophthaled A2B
(manufactured by Ciba), Monolite Yellow 4G (manufactured by ICI), etc. Metal complex azo pigment Irgazine Yellow 5GT (manufactured by Ciba), Paliotol Yellow 1770
(manufactured by BASF) etc. Penzimidazolone pigments Hostapalm Yellow H3G (manufactured by Hoechst), Hostapalm Orange HL70 (manufactured by Hoechst), Novapalm Orange HL (manufactured by Hoechst), etc. Quinacridone pigments Shinkasha Red Y (manufactured by Dupont), Shinkasha Violet (manufactured by Dupont), Hoster Palm Red (manufactured by Hoechst),
Paris Augen Red (manufactured by BASF), Monolite Violet (manufactured by ICI), etc. Isoindolinone pigments Irgazine Yellow 2RLT (manufactured by Ciba), Palitor Yellow 2140HD (manufactured by BASF), etc. Quinophthalone pigment Paliotol Yellow 0960HD
(manufactured by BASF) etc. Perinone pigment Hoster Palm Orange GR (manufactured by Hoechst), etc. Perylene pigments Irgazin Red BPT (manufactured by Ciba), Nova Palm Red BL (manufactured by Hoechst), Paliogen Red 3910 (manufactured by BASF), etc. Dioxazine pigments Chromophthal Violet (manufactured by Ciba), Hoster Palm Violet RL (manufactured by Hoechst), Dioxazine Violet (manufactured by Sumitomo Chemical), etc. Phthalocyanine pigments Chromophthal Blue 4GN (manufactured by Ciba), Hostapalm Blue B3G (manufactured by Hoechst), Syncasia Blue GF (manufactured by Dupont), Chromophthal Green GF (manufactured by Ciba), Hostapalm Green GG (manufactured by Hoechst) ), Shinkasiya B
(manufactured by DuPont) etc. Thioindigo pigment Nova Palmlet Violet MRS (manufactured by Hoechst),
Thiophore Stretch MVE6606 (manufactured by BASF)
etc. Anthraquinone pigment chromophthaled
A3B (manufactured by Ciba), etc. Flavanthrone pigments Chromophthal Yellow A2R (manufactured by Ciba), Monolite Yellow FR (manufactured by ICI), etc. Indanthrene pigments Chromophthal Blue A3R (manufactured by Ciba), Monolight Blue 3R (manufactured by ICI), Thren Blue 6011 (manufactured by Dainippon Ink), etc. Anthrapyrimidine pigment Paliogen Yellow 1560 (manufactured by BASF), etc. Anth Anthrone pigment Monolight Red 2Y (manufactured by ICI),
Monolight Red Y (manufactured by ICI), Hostapalm Scarlet GO (manufactured by Hoechst), etc. Pyranthrone pigment Parisogenred 3530 (manufactured by BASF)
etc. Examples include various organic pigments such as. The method for modifying a hydrophobic organic substance according to the present invention is carried out by irradiating the hydrophobic organic substance with low-temperature plasma. Power sources for generating such low-temperature plasma include high frequency, microwave, direct current, alternating current, etc., and discharge types include glow discharge, corona discharge, boxer charge, etc. due to inductive load and capacitive load. When treating hydrophobic organic substances using such plasma at low pressure, the degree of vacuum in the treatment tank should be 0.01 to 10 mmHg, preferably 0.05 to 5 mmHg.
mmHg. On the other hand, when processing at normal pressure, the processing can be carried out directly in the atmosphere or by bringing the processing gas into contact with the substance to be processed. By using an oxide gas such as CO ₂ as the plasma gas, hydrophobic organic substances are modified into organic substances with good water dispersibility in an extremely high yield while preventing ashing. Furthermore, low-temperature plasma treatment using suboxide gases such as NO, N ₂ O, CO, and SO ₂ has poor reforming effects, but by mixing a small amount of oxygen gas with these gases, excellent reforming effects can be obtained. It was also successful in exerting a reforming effect. Moreover, in this case, there is an advantage that the exhaust gas contains NO ₂ , CO ₂ , SO _{3 ,} etc., and the processing operation is easy. The present invention will be explained below by way of examples. Example 1 Pyrex plasma chamber (inner diameter 7 cm, length approx.
A Pyrex sample board containing 3 g of furnace-type carbon black (Mitsubishi #44) was placed in the center of each plasma chumper of a low-temperature plasma ashing device equipped with four pieces (16 cm), and the inside of the chumper was
After degassing for 1 hour at 0.5 mmHg,
Modified carbon black was manufactured by maintaining a plasma state for 2 hours at a high frequency output of 2 W while flowing carbon dioxide gas at a rate of ml/min. Unmodified carbon black is difficult to wet with water and has extremely poor dispersibility in water or in an aqueous vehicle, whereas the modified carbon black produced in this example is extremely wettable in water and has poor dispersibility in water or in an aqueous vehicle. Above all, the dispersibility was excellent, and a uniform and extremely good dispersion state was obtained with short stirring. Also, add 1g of sample to 100ml of water and boil for 15 minutes.
After being left for 48 hours, the pH of the suspension was measured and found that while the unmodified carbon black had a pH of 7.2, the modified carbon black had a pH of 3.6, indicating that the particle surface was oxidized and a considerable amount of acidic oxidation products were produced. The existence of was recognized. Example 2 Under the same conditions as Example 1, the plasma treatment time was changed to 4 hours. As a result, the water dispersibility was extremely good as in Example 1, and the pH was 3.1. Example 3 In Example 1, modified carbon black was obtained by changing the high frequency output during the low temperature plasma treatment to 5W and the treatment time to 2 hours and 4 hours. Both have good water dispersibility and pH is 3.4 and 3.0 respectively.
It was hot. Example 4 High frequency output of 2W and 5W under the same conditions as Example 1
The weight changes of the modified carbon black and the modified carbon black subjected to low-temperature plasma treatment using oxygen gas alone under the same conditions were as follows.

[Table] That is, the low-temperature plasma treatment using carbon dioxide gas according to the reforming method of the present invention causes much less ashing than the method using oxygen gas, and therefore has an extremely high yield.
A carbon black product with excellent water dispersibility was obtained. Example 5 Using the same equipment as in Example 1, 3 g of each of the hydrophobic organic pigments (1) to (6) shown below were treated with a high frequency output of 10 W, a carbon dioxide gas flow rate of 100 ml/min, and a treatment time of 2 hours, and then treated with benzene. The mixture was placed in a colorimetric tube containing the same volume of liquid and water, shaken vigorously, and left to stand for 10 minutes.The result of examining whether the modified organic pigment migrated to the benzene layer or the aqueous layer was that it was not modified. All the organic pigments migrated to the benzene layer, whereas almost all the modified organic pigments migrated to the water layer, indicating that excellent water dispersibility was imparted. (1) Sudan (CI12055) (2) Sudan (CI12140) (3) Sudan (CI26100) (4) Sudan (CI26105) (5) Inchigo (6) Phthalocyanine Blue Example 6 Carbon monoxide was used as the treatment gas in Example 1 Using a mixed gas of gas and oxygen gas (mixing ratio 2:1), the high frequency output was 10W, and the processing time was 2 hours and 4 hours.
Modified carbon black was obtained over time. Both had good water dispersibility and pH values of 3.2 and 3.0, respectively. It was confirmed that most of the exhaust gas in this case was carbon dioxide gas. As described above, the method for modifying a hydrophobic organic substance according to the present invention is extremely compatible with water,
This invention is a method for highly efficiently producing a product with excellent dispersibility even in an aqueous vehicle, such as an aqueous solution of a water-soluble maleic acid resin, while preventing loss due to ashing. This invention has completed a practical method for producing water- or aqueous vehicle-dispersible coloring materials, which has been desired in the industrial, pharmaceutical, and plastic industries.

Claims (1)

[Scope of Claims] 1. A method for modifying a hydrophobic organic substance, which comprises making the hydrophobic organic substance water-dispersible by treating the hydrophobic organic substance with low-temperature oxide gas plasma. 2. The method for modifying a hydrophobic organic substance according to claim 1, in which carbon black is used as the hydrophobic organic substance and carbon dioxide gas is used as the oxide gas. 3. A method for modifying a hydrophobic organic substance according to claim 1, using an organic pigment as the hydrophobic organic substance. 4. A method for modifying a hydrophobic organic substance according to claim 1, wherein a small amount of oxygen gas is mixed into suboxide gas and a low temperature plasma treatment is performed.