JP3027412B2 - Organic surface treatment agent - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an organic surface treating agent. That is, as an inorganic material, in particular, as a general surface treatment agent / dispersant for inorganic powder,
An object of the present invention is to provide an organic surface treating agent suitable for improving the dispersibility in a solvent by performing a surface treatment of an inorganic powder.

BACKGROUND ART In general, the surfaces of inorganic materials and inorganic powders are hydrophilic, and thus are poor in wettability and dispersibility in organic solvents and polymer binders. For this reason, in the production of paints and the like, studies have been made on the surface modification of inorganic materials and inorganic powders with a silane coupling agent or the like (Chemical Review No.44 "Surface Modification" (The Chemical Society of Japan) Jenkai Publishing Center)).

The dispersibility of this inorganic powder is also particularly important in the production of magnetic coatings. This is because the recording density of a magnetic recording medium made by using this is directly related to the dispersibility.

Therefore, in the field of magnetic paints, in order to improve the dispersibility of magnetic powders and fillers, as a dispersant, at least one terminal of a lipophilic molecular skeleton has a hydrophilic or reactive functional group. Based on the basic idea that dispersibility can be improved, conventionally, these powders have been treated using a fatty acid or various surfactants as a surface treatment agent (JP-A-58-102504), Surface modification with a silane coupling agent or a titanium coupling agent has been performed (Japanese Patent Application Laid-Open Nos. 55-12539 and 56-58135).

On the other hand, as an organic solvent suitable for dissolving an organic substance, toluene, MEK, ethyl acetate, THF, and the like are used. Ethyl acetate contains ester groups, THF contains ether groups, M
EK contains a ketone group and toluene contains a phenyl group.

However, conventional fatty acids, silane coupling agents, and the like do not have an ester group, an ether group, a phenyl group, or the like in the skeleton of the molecule, and thus have poor affinity for these organic solvents.

Furthermore, since the average molecular weight of these fatty acids and silane coupling agents is very small, the distance between inorganic powders cannot be increased. As a result, the inorganic powders that have been dispersed with each other eventually re-aggregate.

Therefore, these fatty acids and silane coupling agents were insufficient to stably disperse the inorganic powder in the presence of the organic solvent.

On the other hand, a hydrophilic or reactive functional group such as a sulfonic acid group, a phosphoric acid group, a carboxylic acid group, a salt thereof, and a tertiary amino group is contained in a polymer chain in a polymer binder to reduce the inorganic powder of the binder itself. Attempts have been made to increase the dispersibility (JP-A-56-13520, JP-A-55-117734, JP-A-1-13223, etc.), but the dispersion is still insufficient, and a new surface treatment for improving the dispersibility has been attempted. The advent of the technique was desired.

The present invention solves the above-mentioned insufficiency of the conventional surface treatment technology, secures a molecular size that can separate the distance between inorganic powders, and adds a hydrophilic or reactive functional group to the molecular chain. It is an object of the present invention to provide an organic surface treating agent which exhibits an excellent surface treatment effect in a very small amount by arranging it at the end to maximize the function of a hydrophilic or reactive functional group.

DISCLOSURE OF THE INVENTION Accordingly, the present inventors have conducted intensive studies to further improve the surface treatment effect, and as a result, first, a sulfonic acid group,
Phosphoric acid groups, carboxylic acid groups and their salts and introducing a hydrophilic or reactive functional group such as a tertiary amino group at the molecular terminal, second, the number average molecular weight is 800 or more, preferably 25,000 or less, More desirably, it is controlled within the range of 1500 to 10,000.
It has been found that by arranging more than one, it is possible to provide an organic surface treating agent capable of significantly improving the surface modification effect of an inorganic material, particularly an inorganic powder.

The reason is that the hydrophilic or reactive functional group introduced at the molecular end adsorbs or reacts on the surface of the inorganic material as an adsorption anchor. It is thought that the adsorbed or reacted molecules are arranged as if they were combs, and the surface is changed from hydrophilic to lipophilic, especially to organic solvent, and the dispersibility of the powder is particularly enhanced.

As hydrophilic or reactive functional groups, -COOMe, -N
_{H 3, -NH 2 R, -NRR} ', - NH 3 +, -NH 2 R +, -NHRR' +,
−NRR′R ″ ⁺ , −SO ₃ X, −OSO ₃ X, −OP (O) (OX) ₂ , −OP
(O) (OX) (OR), -OP (O) (OR) ₂ , -P (O) (OX) ₂ ,-
P (O) (OX) (OR), -P (O) (OR) ₂ , -N = C = O,
And —CH (O) CH ₂ (where Me = metal, X = H or metal, R, R ′, R ″ = alkyl group), preferably —COOMe, —NH ₂ , -NHR, -NR
_{R ', - SO 3 X,} -OSO 3 X, -OP (O) (OX) 2, -P (O) (OX) 2,
And more preferably a structure selected from —CH (O) CH ₂ (where Me = metal, X = H or metal, and R, R ′ = alkyl).

Also, the chain backbone side chains, -COOH, -OH, -NH _2, and -NHR, -NRR ', - CH ( O) CH 2, and either one of an ammonium salt (wherein, R, R ′ = alkyl group) can further enhance this surface modification effect.

The method for synthesizing this kind of organic substance is not particularly limited.For example, vinyl polymerization may be performed using a polymerization initiator having a hydrophilic functional group such as COOH, or a hydrophilic or reactive functional group may be used. A macromonomer method using a chain transfer agent having the same may be used.

As the polymerization initiator, α, α′-azobisisobutylnitrile, benzoyl peroxide and the like can be used,
As the chain transfer agent, thioglycerin, thioglycolic acid, 2-mercaptoethanesulfonic acid sodium salt, mercaptobenzothiazole and the like can be used.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, specific examples of the present invention will be described,
The present invention is not limited to these examples.

<< Synthesis of Surface Treatment Agent >> Example 1 Methyl methacrylate 0.9 mol parts by weight α, α′-azobisisobutyronitrile 0.01 mol parts by weight thioglycerin 0.03 mol parts based on 100 parts by weight of the total amount of the above synthetic starting materials As a solvent, 100 parts by weight of THF was used.

Take the above mixture into a flask equipped with a condenser, sufficiently purge the system with nitrogen, and then stir well at 60 ° C for 20 minutes.
Allowed to react for hours. The reaction product was purified by reprecipitation in petroleum ether and water, and dried under reduced pressure at 60 ° C. for 8 hours.

The number average molecular weight of the obtained organic surface treating agent was 3.0 × 10 ³ by a vapor pressure infiltration method. The introduction of the hydroxyl group was confirmed by NMR and IR. Further, it was confirmed by thin-layer chromatography and high-resolution NMR that the hydroxyl groups were uniformly introduced into the molecular terminals.

As a result, the molecular structure of this organic surface treatment agent is as follows: Was able to be determined.

Example 2 0.9 mol parts by weight of methyl methacrylate 0.02 mol parts by weight of 2-hydroxyethyl methacrylate 0.01 mol parts by weight of α, α'-azobisisobutyronitrile 0.03 mol parts by weight of thioglycolic acid Total amount of the above synthetic starting materials 100 parts by weight As a solvent, 60 parts by weight of THF and 40 parts by weight of ethanol were used.

Take the above mixture into a flask equipped with a condenser, sufficiently purge the system with nitrogen, and then stir well at 60 ° C for 20 minutes.
Allowed to react for hours. The reaction product was purified by reprecipitation in petroleum ether and water, and dried under reduced pressure at 60 ° C. for 8 hours. The number average molecular weight of the obtained organic surface treatment agent was 3.4 by the vapor pressure osmosis method.
× was 10 ^3. The introduction of the hydroxyl group was confirmed by NMR and IR. In addition, it was confirmed by thin-layer chromatography and high-resolution NMR that the carboxyl group was uniformly introduced into the molecular terminal.

As a result, the molecular structure of this organic surface treatment agent is as follows: Was able to be determined.

Example 3 0.9 mol parts by weight of methyl methacrylate 0.02 mol parts by weight of 2-hydroxyethyl methacrylate 0.01 mol parts by weight of α, α'-azobisisobutyronitrile 0.03 mol parts by weight of sodium salt of 2-mercaptoethanesulfonic acid As a solvent, 20 parts by weight of THF and 40 parts by weight of ethanol were used with respect to 100 parts by weight of the total amount.

Take the above mixture into a flask equipped with a condenser, sufficiently purge the system with nitrogen, and then stir well at 60 ° C for 20 minutes.
Allowed to react for hours. During the polymerization, 40 parts by weight of THF was added. The reaction was purified by reprecipitation in petroleum ether and water followed by purification.
It dried under reduced pressure at 8 degreeC for 8 hours. The number average molecular weight of the obtained organic surface treating agent was 4.1 × 10 ³ by a vapor pressure infiltration method. Also,
The introduction of the hydroxyl group was confirmed by NMR and IR. Further, it was confirmed by thin-layer chromatography and high-resolution NMR that the sulfonate sodium salt was uniformly introduced into the molecular terminal.

As a result, the molecular structure of this organic surface treatment agent is as follows: Was able to be determined.

Example 4 0.9 mol parts by weight of methyl methacrylate 0.02 mol parts by weight of 2-hydroxyethyl methacrylate 0.01 mol parts by weight of α, α′-azobisisobutyronitrile 0.035 mol parts by weight of mercaptobenzothiazole Total amount of the above synthetic starting materials 100 parts by weight 100 parts by weight of THF was used as a solvent per part.

Take the above mixture into a flask equipped with a condenser, sufficiently purge the system with nitrogen, and then stir well at 60 ° C for 20 minutes.
Allowed to react for hours. The reaction product was purified by reprecipitation in petroleum ether and water, and dried under reduced pressure at 60 ° C. for 8 hours. The number average molecular weight of the obtained organic surface treatment agent is 2.5 × 1 by the vapor pressure infiltration method.
0 was ³ . The introduction of the hydroxyl group was confirmed by NMR and IR. In addition, it was confirmed by thin-layer chromatography and high-resolution NMR that the benzothiazole group was uniformly introduced into the molecular terminal.

As a result, the molecular structure of this organic surface treatment agent is as follows: Was able to be determined.

Example 5 Synthesis was performed using styrene in place of methyl methacrylate in Example 2, and after the synthesis reaction, an ethanol solution of sodium hydroxide (0.006 mol parts by weight of sodium hydroxide) was added. The carboxylate was confirmed. The number average molecular weight of the obtained organic surface treating agent was 3.3 × 10 ³ by a vapor pressure infiltration method.

As a result, the molecular structure of this organic surface treatment agent is as follows: Was able to be determined.

Example 6 After the synthesis reaction in Example 1, 0.1 mol parts by weight of phosphorus oxychloride was added, and the mixture was stirred well at room temperature for 2 days. Next, the organic surface treating agent was thoroughly washed with water. Thereafter, purification was carried out in the same manner, and the phosphoric acid at the molecular end was confirmed. The number average molecular weight of the obtained organic surface treating agent was 3.2 × 10 ³ by a vapor pressure infiltration method.

As a result, the molecular structure of this organic surface treatment agent Was able to be determined.

Example 7 To the organic surface treating agent obtained in Example 6, sodium hydroxide was added in the same manner as in Example 5. Next, the phosphoric acid at the molecular end was confirmed. The number average molecular weight of the obtained organic surface treating agent was 3.0 × 10 ³ by a vapor pressure infiltration method.

As a result, the molecular structure of this organic surface treatment agent is as follows: Was able to be determined.

Example 8 0.9 mol parts by weight of methyl methacrylate 0.01 mol parts by weight of α, α'-azobisisobutyronitrile 0.013 mol parts by weight of thioglycerin 100 parts by weight of the total amount of the above synthetic starting materials 100 parts by weight of THF as a solvent Part was used.

Take the above mixture into a flask equipped with a condenser, sufficiently purge the system with nitrogen, and then stir well at 60 ° C for 20 minutes.
Allowed to react for hours. The reaction product was purified by reprecipitation in petroleum ether and water, and dried under reduced pressure at 60 ° C. for 8 hours. The number average molecular weight of the obtained organic surface treatment agent was 5.3 × 1 by vapor pressure osmosis.
0 was ³ . The introduction of the hydroxyl group was confirmed by NMR and IR. Further, it was confirmed by thin-layer chromatography and high-resolution NMR that the hydroxyl groups were uniformly introduced into the molecular terminals.

As a result, the molecular structure of this organic surface treatment agent is as follows: Was able to be determined.

Example 9 0.9 mol parts by weight of methyl methacrylate 0.007 mol parts by weight of α, α'-azobisisobutyronitrile 0.005 mol parts by weight of thioglycerin 100 parts by weight of THF as a solvent with respect to 100 parts by weight of the total amount of the above synthetic starting materials Was used.

Take the above mixture into a flask equipped with a condenser, sufficiently purge the system with nitrogen, and then stir well at 60 ° C for 20 minutes.
Allowed to react for hours. The reaction product was purified by reprecipitation in petroleum ether and water, and dried under reduced pressure at 60 ° C. for 8 hours. The number average molecular weight of the obtained organic surface treatment agent was 8.9 × 1 by a vapor pressure osmosis method.
0 was ³ . The introduction of the hydroxyl group was confirmed by NMR and IR. Further, it was confirmed by thin-layer chromatography and high-resolution NMR that the hydroxyl groups were uniformly introduced into the molecular terminals.

As a result, the molecular structure of this organic surface treatment agent is as follows: Was able to be determined.

Example 10 0.9 mol parts by weight of methyl methacrylate 0.02 mol parts by weight of 2-hydroxyethyl methacrylate 0.01 mol parts by weight of α, α'-azobisisobutyronitrile 0.03 mol parts by weight of mercaptopropionic acid Total amount of the above synthetic starting materials 100 parts by weight As a solvent, 100 parts by weight of THF was used.

Take the above mixture into a flask equipped with a condenser, sufficiently purge the system with nitrogen, and then stir well at 60 ° C for 20 minutes.
Allowed to react for hours. The reaction product was purified by reprecipitation in petroleum ether and water, and dried under reduced pressure at 60 ° C. for 8 hours. The number average molecular weight of the obtained organic surface treatment agent was 3.4 × 1 by the vapor pressure infiltration method.
0 was ³ . The introduction of the hydroxyl group was confirmed by NMR and IR. In addition, the fact that the carboxyl group is uniformly introduced at the molecular end can be confirmed by thin-layer chromatography and high resolution.
Confirmed by NMR.

As a result, the molecular structure of this organic surface treatment agent is as follows: Was able to be determined.

Example 11 0.9 mol parts by weight of styrene α, α′-azobisisobutyronitrile 0.01 mol parts by weight 0.03 mol parts by weight of 3-mercaptopropyltrimethoxysilane 0.03 mol parts by weight , THF, 100 parts by weight.

Take the above mixture into a flask equipped with a condenser, sufficiently purge the system with nitrogen, and then stir well at 60 ° C for 20 minutes.
Allowed to react for hours. The reaction product was purified by reprecipitation in petroleum ether and water, and dried under reduced pressure at 60 ° C. for 8 hours. The number average molecular weight of the obtained organic surface treatment agent was 5.1 × 1 by the vapor pressure infiltration method.
0 was ³ . Further, it was confirmed by thin-layer chromatography and high-resolution NMR that the trimethoxysilyl group was uniformly introduced into the molecular terminal.

As a result, the molecular structure of this organic surface treatment agent is as follows: Was able to be determined.

Example 12 0.9 mol parts by weight of methyl methacrylate 0.02 mol parts by weight of 2-hydroxyethyl methacrylate 0.02 mol parts by weight of dimethylaminoethyl methacrylate 0.01 mol parts by weight of α, α'-azobisisobutyronitrile 0.03 mol parts by weight of mercaptopropionic acid 100 parts by weight of THF was used as a solvent with respect to 100 parts by weight of the total amount of the synthesis starting materials.

Take the above mixture into a flask equipped with a condenser, sufficiently purge the system with nitrogen, and then stir well at 60 ° C for 20 minutes.
Allowed to react for hours. The reaction product was purified by reprecipitation in petroleum ether and water, and dried under reduced pressure at 60 ° C. for 8 hours. The number average molecular weight of the obtained organic surface treatment agent was 3.7 × 1 by the vapor pressure infiltration method.
0 was ³ . In addition, introduction of hydroxyl group and amino group is performed by NMR.
And IR. In addition, it was confirmed by thin-layer chromatography and high-resolution NMR that the carboxyl group was uniformly introduced into the molecular terminal.

As a result, the molecular structure of this organic surface treatment agent is as follows: Was able to be determined.

The effects of the above 12 kinds of organic surface treating agents according to the present invention will be described below in order.

First, regarding the surface modification effect of the powder of the present invention,
This will be described by taking titanium oxide as an example.

Application Example 1 100 parts by weight of substantially spherical white titanium oxide having an average diameter of 1 μm was placed in a three-necked flask equipped with a cooling tube and a stirrer, and 400 parts by weight of toluene and 400 parts by weight of MEK were added.
2 parts by weight of the organic surface treating agent prepared in 1) was added and stirred well for 2 hours, and then refluxed for 8 hours while stirring well. After standing at room temperature for 72 hours, the mixture was filtered and aged at 50 ° C. for 4 hours. Next, the titanium oxide was thoroughly washed.

Application Example 2 The organic surface treatment agent prepared in Example 2 was used in place of the organic surface treatment agent prepared in Example 1 in Application Example 1.

Application Example 3 The organic surface treatment agent produced in Example 3 was used in place of the organic surface treatment agent produced in Example 1 in Application Example 1.

Reference Example 1 A surfactant surfactant di-2-ethylhexyl sodium sulfosuccinate (trade name: Aerosol OT, manufactured by Nacalai Tesque) was used in place of the organic surface treating agent prepared in Example 1 in Application Example 1.

Reference Example 2 The silane coupling agent octadecyltriethoxysilane (manufactured by Chisso Corporation) was used instead of the organic surface treatment agent prepared in Example 1 in Application Example 1.

Reference Example 3 In Application Example 1, titanium coupling agent trade name TTS (manufactured by Ajinomoto Co.) was used in place of the organic surface treatment agent prepared in Example 1 in Application Example 1.

Using the untreated titanium oxide as reference example 4 in addition to the titanium oxide surface-treated in application examples 1 to 3 and reference examples 1 to 3, the sedimentation volume in the MEK solvent was measured as follows.

1.0 g of titanium oxide was placed in a sample tube, 100 g of MEK was added, and the mixture was ultrasonically dispersed for 6 hours. The sedimentation volume after standing for 12 hours was measured. Table 1 shows the results.

Table 1 Sedimentation volume (cm ³ ) Application 1 1.3 Application 2 0.9 Application 3 0.9 Reference 1 2.7 Reference 2 2.8 Reference 3 3.1 Reference 4 6.2 Thus, according to the organic surface treating agent of the present invention. In addition, the inorganic powder can be well dispersed. This is evident from the reduced sedimentation volume described above.

Next, regarding the surface modification effect of the inorganic material of the present invention, a stainless plate (Ra = 0.1 μ
m) will be described as an example.

Application Example 4 An organic surface treating agent synthesized from a stainless steel plate in Example 1 was used.
After being immersed in a MEK solution containing 1% by weight for 2 hours, aging was performed at 50 ° C. for 4 hours. Next, the plate was thoroughly washed with MEK.

Application Example 5 The organic surface treatment agent synthesized in Example 3 was used in place of the organic surface treatment agent synthesized in Example 1 in Application Example 4.

Reference Example 5 The silane coupling agent used in Reference Example 2 was used instead of the organic surface treatment agent synthesized in Example 1 in Application Example 4.

Reference Example 6 The titanium coupling agent used in Reference Example 3 was used in place of the organic surface treating agent synthesized in Example 1 in Application Example 4.

The contact angle between water and toluene was measured using an untreated stainless steel plate as Reference Example 7 in addition to the stainless steel plates subjected to the surface treatment in Application Examples 4 and 5 and Reference Examples 5 and 6. Table 2 shows the results.

From the above results, it can be seen that the surface condition of the inorganic material can be improved from hydrophilic to amphiphilic with the organic surface treating agent of the present invention.

Further, the organic surface treating agent of the present invention can be used not only for simply changing the surface condition of the inorganic material, but also for a specific industrial product manufacturing process. In particular, the usefulness of the present invention will be described with an example of a surface treatment process of a ferromagnetic powder in the production of a magnetic paint or a magnetic recording medium in which a ferromagnetic powder needs to be sufficiently dispersed as an inorganic powder.

Reference Example 8 Ferromagnetic powder (coercive force 1500 oersted, 300 parts by weight saturation magnetization 120 emu / g) PVC-vinyl acetate-vinyl alcohol copolymer (UCC VAG)
H) 65 parts by weight Carbon black 10 parts by weight Alumina powder 10 parts by weight Myristic acid 3 parts by weight n-butyl stearate 6 parts by weight Cyclohexanone 395 parts by weight Toluene 395 parts by weight A composition having the above composition is mixed and dispersed by a sand grinder mill. Thus, a magnetic paint was prepared. After adding 10 parts by weight of a polyfunctional isocyanate cross-linking agent to this paint, it is applied and dried on a 14 μm-thick polyethylene film so that the thickness after drying becomes about 2.5 μm. After calendering, it is cut into 8 mm width. To produce a magnetic tape.

REFERENCE EXAMPLE 9 Instead of the vinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) of Reference Example 8, a PVC-based organic surface treating agent containing a sulfonate and a hydroxyl group (MR11 manufactured by Sekisui Chemical)
A magnetic tape was produced in the same manner as in Reference Example 8 except that (0) was used.

Application Example 6 In place of 65 parts by weight of the polyvinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) of Reference Example 8, 60 parts by weight of a vinyl acetate-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) was used. A magnetic tape was produced in the same manner as in Reference Example 8, except that 5 parts by weight of the organic surface treating agent synthesized in Example 1 was used.

Application Example 7 In place of 65 parts by weight of the polyvinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) of Reference Example 8, 60 parts by weight of the vinyl acetate-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) was used. A magnetic tape was produced in the same manner as in Reference Example 8 except that 5 parts by weight of the organic surface treating agent synthesized in Example 2 was used.

Application Example 8 Instead of 65 parts by weight of the vinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) of Reference Example 8, 60 parts by weight of a vinyl acetate-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) was used. A magnetic tape was produced in the same manner as in Reference Example 8, except that 5 parts by weight of the organic surface treating agent synthesized in Example 3 was used.

Application Example 9 Instead of 65 parts by weight of the polyvinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) of Reference Example 8, 60 parts by weight of a vinyl acetate-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) was used. A magnetic tape was produced in the same manner as in Reference Example 8, except that 5 parts by weight of the organic surface treating agent synthesized in Example 4 was used.

Application Example 10 Instead of 65 parts by weight of the vinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) of Reference Example 8, 60 parts by weight of the vinyl acetate-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) was used. A magnetic tape was produced in the same manner as in Reference Example 8, except that 5 parts by weight of the organic surface treating agent synthesized in Example 5 was used.

Application Example 11 In place of 65 parts by weight of the polyvinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) of Reference Example 8, 60 parts by weight of a vinyl acetate-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) was used. A magnetic tape was produced in the same manner as in Reference Example 8, except that 5 parts by weight of the organic surface treating agent synthesized in Example 6 was used.

Application Example 12 Instead of 65 parts by weight of the vinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) of Reference Example 8, 60 parts by weight of the vinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) was used. A magnetic tape was produced in the same manner as in Reference Example 8 except that 5 parts by weight of the organic surface treating agent synthesized in Example 7 was used.

Application Example 13 Instead of 65 parts by weight of the polyvinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) of Reference Example 8, 60 parts by weight of a vinyl acetate-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) was used. A magnetic tape was produced in the same manner as in Reference Example 8, except that 5 parts by weight of the organic surface treating agent synthesized in Example 8 was used.

Application Example 14 Instead of 65 parts by weight of the polyvinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) of Reference Example 8, 60 parts by weight of the vinyl acetate-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) was used. A magnetic tape was produced in the same manner as in Reference Example 8, except that 5 parts by weight of the organic surface treating agent synthesized in Example 9 was used.

Application Example 15 Instead of 65 parts by weight of the polyvinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) of Reference Example 8, 60 parts by weight of a vinyl acetate-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) was used. A magnetic tape was produced in the same manner as in Reference Example 8, except that 5 parts by weight of the organic surface treating agent synthesized in Example 10 was used.

Application Example 16 Instead of 65 parts by weight of the polyvinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) of Reference Example 8, 60 parts by weight of the vinyl acetate-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) was used. A magnetic tape was produced in the same manner as in Reference Example 8, except that 5 parts by weight of the organic surface treating agent synthesized in Example 11 was used.

Application Example 17 Instead of 65 parts by weight of the vinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) of Reference Example 8, 60 parts by weight of the vinyl chloride-vinyl acetate-vinyl alcohol copolymer (VAGH manufactured by UCC) was used. A magnetic tape was produced in the same manner as in Reference Example 8, except that 5 parts by weight of the organic surface treating agent synthesized in Example 12 was used.

Each magnetic tape obtained in the above application example was assembled into an 8 mm video cassette, and chroma S / N
The ratio, C / N ratio, and RF output were measured. Table 3 shows the measurement results. However, application examples 6-7, 9 and 13-17 are comparative application examples.

The above results show that the organic surface treating agent of the present invention contributes to the improvement of the dispersibility of the ferromagnetic powder.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-210467 (JP, A) JP-A-57-50535 (JP, A) JP-A-62-265301 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) C09C 3/10

Claims (5)

(57) [Claims] An acrylic resin as a chain skeleton, having two or more side chains containing an ester group, an ether group, a ketone group or a phenyl group in the chain of the skeleton, and having at least one side chain of the skeleton. -COOMe, -NH ₃ ,-
_{NH 2 R, -NRR ', -} NH 3 +, -NH 2 R +, -NHRR' +, -NRR '
_{^{R "+, -SO 3 X,}} -OSO 3 X, -OP (O) (OX) 2, -OP (O)
(OX) (OR), -OP (O) (OR) ₂ , -P (O) (OX) ₂ , -P
(O) (OX) (OR ), - P (O) (OR) 2, -N = C = O, and -CH (O) CH ₂ (where, Me = metal, X = H or a metal,
R, R ′, R ″ = alkyl group), a hydrophilic or reactive functional group having a number average molecular weight of 300 or more. 2. The method according to claim 1, wherein the hydrophilic or reactive functional group is -NH ₂ , -N
_{HR, -NRR ', - SO 3} X, -OSO 3 X, -OP (O) (OX) 2, -P (O)
(OX) ₂ , and —CH (O) CH ₂ (where X = H or a metal,
2. The organic surface treating agent for inorganic powder according to claim 1, wherein the organic surface treating agent has a structure selected from the group consisting of: R, R '= alkyl group). 3. A chain-like side chain having -COOH, -OH, -N
_{H 2, -NHR, -NRR ',} - CH (O) CH 2, and ammonium salts (wherein, R, R' = an alkyl group) claims, characterized in that it comprises a group selected from the group consisting of Item 7. The organic surface treating agent according to Item 1. 4. The organic surface treating agent for inorganic powder according to claim 1, wherein the number average molecular weight is 800 or more and 25,000 or less. 5. The organic surface treating agent for inorganic powder according to claim 4, wherein the number average molecular weight is 1500 or more and 15,000 or less.