JPS6315865A - Production of thixotropic coating composition - Google Patents

Abstract

PURPOSE:To produce the title compsn. which does not cause secondary agglomeration and has excellent thixotropic properties, anti-sagging properties and pigment suspension, properties, by mechanically dispersing a resin compsn. contg. a specified thixotropic agent. CONSTITUTION:A mono- or diisocyanate compd. (e.g., toluene diisocyanate) is reacted with a 1-5C aliph. monoamine (e.g., n-propylamine) in an inert solvent (e.g., acetone) to obtain a thixotropic agent. At least one resin selected from the group consisting of an alkyd resin, an acrylic resin, a melamine resin, an epoxy resin, a polyester resin, etc., is mixed with 1-10wt% said thixotropic agent to obtain a resin compd. The compn. is mechanically dispersed to obtain a thixotropic coating compsn. having an average particle size of 0.1-5mu.

Description

[Detailed Description of the Invention] [Industrial Field of Application] -1 The present invention relates to a method for producing a NII sacrificial product that has high thixotropy, excellent sag prevention performance, sedimentation prevention performance, etc. Each time it contains a dispersion agent which is a reaction product of a compound and an amine to isocyanate-1! [Relating to a method for producing a coating composition.

BACKGROUND ART 1 A coating composition is generally applied to an object to be coated for the purpose of imparting aesthetic appearance to the object and protecting the object from rust and the like. Particularly in the case of automobile paints, it is desirable to apply a thick film to protect the car body from impacts such as pebbles generated during driving. However, if a liquid coating composition is applied to a vertical surface in one thick coat, sagging will occur, so it has usually been applied in several coats.

By the way, in recent years, Japanese Patent Publication No. 49-99132, Japanese Patent Publication No. 1983-
Patent publications such as No. 23707 disclose thixotropic agents comprising reaction products of isocyanate compounds and amines. When this thixotropic agent is used, high thixotropy is achieved,
It has become clear that a thixotropic coating composition with excellent anti-sag properties can be obtained by 1q. If such a species-modified coating composition is used, vertical surfaces can be coated thickly at one time, thereby reducing the number of man-hours.

In order to prepare a coating composition having this rice malt deterrent, according to the Juki publications, isocyanes 1 to 1 are mixed with an amine in an inert ↑11 solvent and reacted with each other. A method of manufacturing a malt fixing agent, adding it to a coating composition and stirring it to produce a seed-modified coating composition, or a method of reacting by mixing two types of resins in which an isocyanate compound and an amine are mixed separately with stirring. A method for producing a species-modified coating composition by conducting the following steps is disclosed.

[Problems to be Solved by the Invention] As a result of intensive research based on the above-mentioned knowledge, the inventors of the present invention discovered that the grain size of the coating composition of the above-mentioned rice deterrent agent affects the properties of rice and wheat. That is, it has become clear that when the average particle size becomes smaller than 0.1μ, the seed variation 11 decreases significantly and sufficient first sagging performance does not appear. Note that this average particle size means a value measured with a Coulter counter, and is the particle size in a state where the rice deterrent is swollen with melting powder, resin, etc.

By the way, in the method of reacting an isocyanate compound and an amine in a solvent to synthesize a binder each time, and adding the resulting rice malt detergent to the resin and stirring, the rice malt detergent maintains a uniform particle size in the solvent. However, there were cases where it aggregated when mixed into the resin. Once agglomerated, it was not possible to reduce the particle size of the rice and barley detergent by shearing force equivalent to stirring. Therefore, the seed-modified coating composition prepared in this manner has a problem in that its properties are poor and the particle size is too large, causing lumps in the coating film.

In addition, in the method of producing a seed-modified coating composition by reacting isocyanes 1 to 1 with amines in a resin, the rice deterrent does not aggregate and has a fine particle size.

However, if various conditions such as stirring speed and resin viscosity during the reaction are different, the particle size becomes too fine, and the desired rice and wheat properties may not be achieved.

The present invention has been made in view of these problems, and provides a method for producing a coated acid product that exhibits excellent rice and wheat properties and that can easily adjust the particle size to an optimal range. It is.

[Means for Solving the Problems] The method for producing a species-modified coating composition of the present invention involves adding 1) a modifier obtained by reacting isocyanes 1 to 1 with an amine in an inert solvent to a resin composition. and a dispersion step of mechanically dispersing the resin composition combined with the thixotropic agent to obtain an average particle size of 0.1 to 5μ by the rice detergent. It is characterized by

The isocyanate compound used to produce the rice detergent may be monoisocyanate 1- or diisocyanate. Note that it is more preferable to use diisocyanate. This is because, compared to monoisocyanate, a small amount of it shows higher rice properties. Suitable examples of this diisocyanate include tetramethylene-1,
4-diisocyanate, hexamethylene-1,6-diisocyanate, ω,ω--dipropyl ether diisocyanate-1~, diodiprobyl diisocyanate, dicyclohexyl-1,4-diisocyanate, dicyclohexylmethane-4,4 '-diisocyanate, 1,5-
Dimethyl(2,4-ω-diisocyanatomethyl)benzene, 1,5-dimethyl(2,4-ω-diisocyanatoethyl)benzene, 1,3.5-trimethyl(2,4-
ω-diisocyanatommethane)benzene, 1,3.5-triethyl(2,4,-ω-diisocyanatommethy)benzene, isophorone diisocyanate, dicyclohexyldimethylmethane-4,4-diisocyanate, 2 .4
-Toluene diisocyanate, 2.6-1-toluene diisocyanate, diphenylmethane-4,4'-diisocyanate, and the like. hexamethylene-1,6
- diisocyanates or aromatic diisocyanates such as toluene diisocyanate are preferred.

As the amine, a primary or secondary monoamine or polyamine can be used. Among these, monoamines or hydroxymonoamines having 1 to 5 aliphatic carbon atoms are preferred. Such amines include, for example, n-propylamine, tert-butylamine, monoethanolamine,
5-amino 1-pentanol, etc.

The adhesion stopper used in the present invention is prepared by reacting the above-mentioned isocyanate compound with an amine in an inert solvent. Here, the inert solvent is a solvent that does not react with isocyanate compounds and amines, and includes acetone, methyl isobutyl ketone, benzene, toluene, xylene, and aliphatic hydrocarbon solvents such as petroleum ether. It is desirable to use a good solvent for the isocyanate 1-compound and the amine.

The mixing step is a step of mixing the adhesive stopper obtained above with the resin composition. This mixing step can be performed by stirring with a mixer or the like as in the conventional method. tt
The resin composition used is the same as that used in conventional coating compositions, including alkyd resin,
One or a mixture of two or more of acrylic resins, melamine resins, epoxy resins, polyamide resins, polyester resins, etc. can be used.

= 7 = The greatest feature of the present invention lies in the dispersion step. That is, as mentioned in the problem to be solved by the invention, when the adhesive stopper obtained by reacting in a solvent is mixed into the resin, the adhesive stopper may aggregate and the particle size may become large. Therefore, in the present invention, the aggregated adhesive stopper is made fine by mechanically dispersing the mixture of the resin composition and the stopper agent.

This dispersion is carried out so that the average particle size is 0.1 to 5 microns due to the retention agent. If the average particle size is smaller than 0.1 μm, the desired seed modification cannot be obtained, and if it is larger than 5 μm, lumps will appear in the coating film. Therefore, the adhesive is dispersed until the average particle size becomes 0.1 to 5 microns.

Traditionally used for dispersion are Zand Mill, Pebble Mill,
A ball mill, a roll mill, etc. can be used. In order to set the average particle size to 0.1 to 5 .mu., the dispersion time is determined by trial or error depending on the type of dispersion machine, the viscosity of the resin, the amount of the stopper, etc. In addition, when the coating composition contains organic chains, inorganic pigments, etc.
The pigment can also be dispersed around the dispersion process of the rice detergent.

It is desirable that the blocking agent be contained in an amount of 1 to 10% by weight in the total solid content of the coating composition. If the amount is less than 1% by weight, the appearance of seed modification is slight, resulting in poor sagging performance, and if the amount is more than 10 times, the seed modification is too strong, resulting in poor painting workability.

The coating composition after the dispersion process can be blended with various solvents, resins, additives, etc. It is also preferable to disperse the resin at a fairly high concentration.Then, after the dispersion step, a resin and other compounding agents can be further added to the composition to form a coating composition.In this way, 1
Dispersion]: It is efficient because a large amount of rice and wheat coating phase acid can be obtained from the culm.

[Operations and Effects of the Invention 1] In the method for producing a rice-based coated compound of the present invention, a 1-isocyane compound and an amine are reacted with -9= in an inert solvent. By mechanically dispersing the mixture with the composition in a dispersion step, the particle size is made uniform by the stopper agent.

In the mixing process, the stopper agent comes into contact with the resin and aggregates into a shape with large particle size. Then, by mechanically dispersing the mixture in the dispersion step, the average particle size due to the stopper agent can be adjusted to a range of 0.1 to 5 microns. The surface of the dispersed rice deterrent is coated with resin to prevent secondary agglomeration. Therefore, according to the production method of the present invention, it is possible to easily and stably produce a one-step modified coating composition in which the stopper agent has an optimal particle size distribution.

In addition, the obtained coating composition has a high species modification property, and is excellent in anti-sag properties and anti-settling properties on the face.

[Example] The following is a concrete explanation using Examples. Note that all parts mentioned below mean parts by weight.

Example 1 (Production of stopper agent) 4.6 parts of tert-butylamine was added to 100 parts of toluene and stirred to form a uniform solution. 5.4 parts of hexamethylene-1,6-diisocyanate was added dropwise to this solution for 10 minutes while stirring with a mixer, and stirring was continued for an additional 5 minutes to produce a thixotropic agent. .obtained
The thixotropic agent was in the form of a homogeneous translucent gel.

()Kongocho culm) Acrylic resin (Acrydic/I 4-179, large 1
] 140 parts of this ink chemistry (manufactured by @ company, solid content 50%), 140 parts of melamine resin (Super Beckamine G-821, manufactured by Nippon Ink Kagaku Kogyo Co., Ltd., solid content 60%), 50 parts by weight n1 part, rehering agent (Modaflow, Mix 0.5 part of Monlean Tone 1) and 1 part of antioxidant (+J)-L, S-292, Ciba Geigy) and stir evenly, then add 2 parts of the above thixotropic agent (solid content 9%). Mix and stir to bring the mixture to tQ
is.

(Dispersion step) The mixed mixture was dispersed for 1 hour using a 1.0 millimeter (glass beads diameter: 1 mm, filling rate: 50%) to obtain 1 q of the seed-modified coating composition of Example 1.

(Measurement of constants) The particle size, viscosity, and thixotropy index <TI) of the 1q coated composition were measured and the results are shown in the table. The particle size was measured using a 1-Luther counter, and the viscosity was measured using a rotor No. 3 with a BH type viscosity of 81.
The viscosity at 20°C at r p m was measured, and T
The first shift is the viscosity at 2 rpm at 20'C and 2
It is expressed as the ratio of the viscosity of Q r p m.

(Coating film evaluation 1llTi) The 1q coating composition was diluted with Tsurupetz 100 to adjust the viscosity to 25 seconds (N04 food cup, 20°C), and a mild steel plate with electrodeposited and intermediate coat water polished was vertically placed. The coating was applied to a dry film thickness of 50 μm and dried at 130° C. for 30 minutes. The appearance of the obtained test plates was evaluated, and the bark resistance, water resistance, and adhesion were tested, and the results are shown in the table. The weather resistance is 30 on a 4-no-shine weather meter.
The appearance of the coating film after the 00 IIA test was visually evaluated, and the water resistance was evaluated by visual observation of the appearance of the coating film after being immersed in warm water at 7'IO° C. for 10 days. Adhesion was determined by carving 100 squares in a 2 mm square, and counting the number of squares remaining when the cellophane arp was crimped and peeled off.

Comparative Example 1> A coating composition of Example 1 was obtained by using the same mixture of resin and thixotropic agent as in Example 1 and dispersing it in the same sand mill for 5 hours. The constants of the coating composition coated with 1q and the test results of the test panel coated with the coating composition in the same manner as in Example 1 are shown in the table.

Comparative Example 2 A mixture of the same thixotropic agent J3 and resin as in Example 1 was used, and a coating composition was prepared as it was without dispersion. The constants of the coating composition of Comparative Example 2 were also measured in the same manner as in Example 1, and various tests were conducted on test plates after the coating was dried. The results are shown in the table.

Example 2 (Production of thixotropic agent) 4.0 parts of n-propylamine was added to 100 parts of xylene and stirred to form a uniform solution. Then, while stirring with a mixer, 6.0 parts of 2,6-tolunin diisocyanate was added dropwise into this solution over 10 minutes, and the stirring was continued for an additional 5 minutes to produce a thixotropic agent. The modifier was in the form of a homogeneous translucent gel.

Using the above thixotropic agent and the same resin as in Example 1, the mixing step and dispersion step were carried out in the same manner, and the constant was measured in the same manner.
The coating film was tested in the same manner. The results are shown in the table.

<Comparative Example 3.4> Using the mixture after the mixing step of Example 2 above, Comparative Example 1.
A coating composition of Comparative Example 3.4 was obtained in the same manner as in Example 2. Then, the constants were measured in the same manner as in Example 1, and the coating film was tested in the same manner. The results are shown in the table.

Evaluation> It is clear from the table that in Comparative Example 1.3, the average particle size was 0.1μ.
It is smaller and less rice-like.

In Comparative Example 2.4, sag also occurred, the average particle size was around 10 μm, and lumps were generated. On the other hand, the coating composition obtained by the production method of the present invention exhibits high lightning properties and has an average particle size in the range of 0.1 to 5 microns. Therefore, even if the paint is applied thickly on a vertical surface at once, no sagging will occur, and no spots will appear on the paint film. Moreover, various coating film performances are also good.

Patent applicant Aisin Kako Co., Ltd. agent
Patent Attorney Hirodo Okawa Patent Attorney Akio Maruyama

Claims (3)

[Claims] (1) A mixing step of mixing a resin composition with a thixotropic agent obtained by reacting an isocyanate compound and an amine in an inert solvent, and mechanically mixing the resin composition mixed with the thixotropic agent. A method for producing a thixotropic coating composition, comprising a dispersion step of dispersing the thixotropic agent to have an average particle size of 0.1 to 5 microns. (2) The method for producing a thixotropic coating composition according to claim 1, wherein the thixotropic agent is contained in an amount of 1 to 10% by weight in the total solid content. (3) The method for producing a thixotropic coating composition according to claim 1, wherein the isocyanate compound is a diisocyanate compound and the amine is a monoamine having 1 to 5 aliphatic carbon atoms.