JPH05112652A - Method for producing aqueous dispersion type nitrocellulose resin - Google Patents

Abstract

(57) [Summary] [Constitution] The pre-emulsified liquid mixture is introduced into the flow path inside the chamber under pressure, and the liquid mixture is introduced into the chamber in an amount of 100 to 10000 Kg / cm ^2.
Preliminary emulsified liquid mixture of water and nitrocellulose-based resin in a device for emulsifying by colliding with a predetermined flat portion in the flow passage under the pressure of or by colliding the mixed liquids in the flow passage under the pressure. A method for producing an aqueous dispersion type nitrocellulose-based resin, which comprises emulsifying. [Effect] The resin obtained according to the present invention has excellent adhesion to various base materials, water resistance and chemical resistance as in the conventional solvent type.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a novel and useful aqueous dispersion type nitrocellulose resin. More specifically, by using a specific dispersing device, without adding an aqueous dispersant, or by adding a very small amount, or with a very small hydrophilic group content, alkali resistance, water resistance, and adhesion to a substrate The present invention relates to a method for producing a nitrocellulose-based resin for a water-based dispersion type coating, which has excellent properties and excellent water dispersion stability.

[0002]

2. Description of the Related Art In recent years, there has been an urgent need to switch from organic solvent-based paints to water-based paints due to the ignition and explosion of organic solvents in paints, air pollution, occupational safety and hygiene problems.

As a means for aqueous dispersion of conventionally used resins, a large amount of hydrophilic groups such as carboxyl groups and polyether groups are introduced, or a large amount of anionic, cationic and nonionic water dispersants are added. There are many cases.

However, the introduction of a large amount of these hydrophilic components inevitably causes a marked decrease in alkali resistance, water resistance and adhesion to the substrate of the coating film formed. In addition, the decrease in surface tension due to additives causes foaming during spray coating and brush coating.

As described above, the conventional means for making the nitrocellulose resin water-soluble have various drawbacks.
It could not be widely used for general purposes. For this reason,
Various methods have been investigated in order to reduce the amount of hydrophilic components added.

However, if the amount of the hydrophilic component is simply reduced, the viscosity becomes extremely high at the time of dispersion and it becomes difficult to disperse, so use of various dispersers having stronger shearing force is considered. It has been.

For example, there is a method of dispersing using a homomixer. However, in this case, since the shearing force is insufficient, a complete dispersion cannot be obtained, and there is a problem such as separation during storage.

Therefore, in place of the homomixer, various homogenizers, colloid mills, static mixers, and other various dispersers have been investigated for use as means having more mechanical dispersive power.

However, the static mixer is effective for the atomization and dispersion in the case of liquid-liquid mixing which is relatively hydrophilic and has a high viscosity, but the effect of reducing the addition amount of the hydrophilic component is hardly recognized.

A homogenizer consisting of a disc rotating at a high speed and fine slits also has a limit in the rotation speed and the slit spacing, and it is difficult to atomize with sufficient stability. Of these, the Manton-Gorlin colloid mill has the most effective atomization and dispersion effect, but it has a structure in which a high-pressure predispersion liquid is passed between the slits pressed by the force of a strong spring, which is a safety aspect. Since the pressure applied from the device is limited, the amount of the premixed liquid to be injected is injected while pulsating, so that there is a problem that the slit interval changes and the particle diameter of the obtained dispersion liquid fluctuates.

For this reason, it is necessary to repeatedly pass through the slits in applications where long-term stability is required, and it has been extremely difficult to actually manufacture it.

[0012]

DISCLOSURE OF THE INVENTION The present invention has the same acid value as conventional solvent-based nitrocellulose resins for paints,
Another object of the present invention is to provide a method for producing an aqueous dispersion type nitrocellulose-based resin which has good dispersibility in water without adding a dispersant and has excellent long-term storage stability.

[0013]

Therefore, as a result of intensive studies conducted by the present inventors focusing on the above-mentioned problems, a large amount of hydrophilic groups are introduced or dispersed by using a specific emulsifying device. It was found that an aqueous dispersion type nitrocellulose resin having excellent water dispersion stability can be produced without adding an agent, and the present invention has been completed.

That is, in the present invention, the pre-emulsified mixed liquid is introduced into the channel in the chamber under pressure, and the mixed liquid is caused to collide with the flat surface portion in the channel under high pressure, or in the channel under high pressure. A method for producing an aqueous dispersion-type nitrocellulose-based resin, which comprises emulsifying a pre-emulsified mixture of water and a nitrocellulose-based resin with an apparatus for emulsifying the mixed liquids by colliding with each other.

The aqueous dispersion type nitrocellulose resin obtained by the present invention has a very small amount of hydrophilic group,
Substantially free from emulsifiers and protective colloids that are usually used, so that the resulting coating film does not have a marked reduction in alkali resistance, water resistance, and adhesion to substrates, and has excellent coating workability and long-term storage stability. Is.

Next, the apparatus used in the present invention will be specifically described. The chamber of the device according to the invention comprises, in FIG. 1, restraining parts 1, 2 and disks 3, 4 which withstand ultra-high pressure. Each of the disks 3 and 4 is provided with two through holes and an extremely narrowed connecting groove for connecting the two holes. The groove preferably has a diameter of 50 to 1000 μm. Disk 3
Since the fluid passes from the disk 3 to the disk 4, the disk and the disk 4 face inward so that the connecting grooves of the two disks are in contact with each other, and the connecting grooves have a cross shape.
Combined in degrees.

The disk must be able to withstand fluid impingement under high pressure. Therefore, the material of the disk is an inorganic base material such as a sintered metal, a metal oxide, a boride, a carbide, a ceramic such as a nitride, or a mixture thereof, which can withstand ultrahigh pressure.

Next, the present invention will be described in detail with reference to the drawings. First, in FIGS. 1, 2 and 3, a mixed solution of pre-emulsified water and a nitrocellulose-based resin is added in an amount of 5 to 30.
Under pressure of Kg / cm ² , it is supplied to the restraining part 1 in the chamber. The mixed liquid that has entered the restraining portion 1 is divided into two parts, is introduced into the disk 3, and collides with the flat surface portions 5 and 6 of the disk 4 as it is. The mixed liquid colliding with the flat surface is accelerated in the connecting groove 7 of the disk 3 on the side in contact with the disk 4 and flows toward the central portion, and the mixed liquid collides with each other at the central portion 8 of the disk 3. The resin particles are emulsified, dispersed, and crushed by the collision with the flat surface and the collision of the liquids, and are made into ultrafine particles. Next, the mixed liquid flows from the central portion 8 toward the outside through the connecting groove 9 of the disk 4 formed in 90 degrees phase, and is taken out through two holes in the disk 4.

When the mixed solution passes through the two divided channels and the connecting groove in the chamber, the mixed solution is accelerated and the pressure becomes high. In this case, the pressure is 100-10000Kg
It is preferable to adjust it to be / cm ² . 100K
If it is less than g / cm ² , the dispersion is weak, and 10000 Kg /
This is because if it is more than cm ² , the base material is so worn that it cannot withstand long-term use. Depending on the composition of the nitrocellulose-based resin, the water dispersion stability may not be improved so much due to the secondary aggregation, so the pressure is 200 to 3000 Kg /
cm ² is particularly preferred.

The apparatus of the present invention is not limited to the structure shown in FIGS. 1, 2 and 3, and the structure is such that the liquid mixture can be made to collide with a predetermined flat portion in the channel of the chamber under high pressure, or high pressure. Basically, any structure may be used as long as it can cause the mixed liquids to collide with each other in the channel of the chamber below, but it is necessary to sufficiently emulsify, disperse, and crush the resin particles. Is preferably one having a structure capable of causing the liquid or the mixed liquid to collide with the flat surface portion twice or more. For example, as shown in FIG. 4, the structure may be such that the flow path is connected by the connecting groove on the surface where the disk 3a having one hole and the disk 4a having one hole are in contact with each other. As described above, the structure may be such that, after colliding with the center portion of the connecting groove of the disk 3b, it can be taken out through the hole 10 of the disk 4b.

Examples of the new emulsifying apparatus used in the present invention include a Microfluidizer manufactured by Microfluidic Inc. of the United States and a Nanomizer manufactured by Cosmo Instrumentation Co., Ltd. of Japan.

The aqueous dispersion-type nitrocellulose-based resin of the present invention is intended to give acrylic resin and alkyd resin the excellent properties of nitrocellulose such as drying property, solvent resistance and chemical resistance for coatings. In addition to these, it is a nitrocellulose-acrylic resin and a nitrocellulose-alkyd resin. Examples of the nitrocellulose include all nitrocellulose that is generally used for paints such as a high nitro group-containing HIG type and a low nitro group-containing LIG type (both manufactured by Asahi Kasei).

The acrylic resin used in the present invention is
In addition to pure acrylic resins obtained by polymerization of acrylic monomers, all modified acrylic resins such as alkyd-modified acrylic resin, polyester-modified acrylic resin, silicone-modified acrylic resin, amino-modified acrylic resin and the like are targeted.

The alkyd resin means, in addition to pure alkyd resin, oil-free alkyd resin, modified alkyd resin such as acrylic modified alkyd resin, amino modified alkyd resin, phenol modified alkyd resin, silicon modified alkyd resin, epoxy modified alkyd resin, Etc. All alkyd resins are targeted.

The acrylic resin and alkyd resin can be produced by various known methods.
As a monomer that can be used for producing the acrylic resin used in the present invention, all polymerizable monomers having an ethylenic double bond can be used. For example, acid monomers such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, light ester PM (manufactured by Kyoeisha Yushi), methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, etc. Methacrylic acid ester, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate,
Acrylic ester such as dodecyl acrylate, (meth)
Nitrogen-containing monomers such as acrylamide, (meth) acrylonitrile, N-methylol (meth) acrylamide, diacetone (meth) acrylamide, diethylaminoethyl (meth) acrylamide; styrene, vinyltoluene,
Styrene-based monomers such as paratertiary butyl styrene; hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate; itaconic acid esters, maleic acid esters,
Examples include fumaric acid ester citraconic acid ester, vinyl acetate, vinyl alkyl ether, and the like. Any of these can be used in any proportion.

For the polymerization of these monomers, already known polymerization initiators such as potassium persulfate or ammonium,
Hydrogen peroxide, inorganic peroxide compounds such as percarbonates, acyl peroxides (eg benzoyl peroxide), alkyl hydroperoxides (eg tertiary butyl hydroperoxide, p-menthane hydroperoxide), silanes An organic peroxide compound such as an alkyl peroxide (for example, di-tertiary butyl peroxide) or an azobisisobutyronitrile compound is used. The inorganic or organic peroxide compound can also be used as a redox catalyst in combination with a reducing agent.

Raw materials used in the production of the alkyd resin used in the present invention include flaxseed oil, soybean oil, tung oil, rice bran oil, coconut oil, palm oil, safflower oil, fish oil, hydrogenated fish oil,
Heat-polymerized oils of dry oils such as castor oil, dehydrated castor oil, flaxseed oil and tung oil, these fatty acids, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, succinic acid, adipic acid, sebacic acid, benzoic acid Acid, alkyl benzoic acid, and other monovalent and polycarboxylic acids, ethylene glycol, propylene glycol, neopentyl glycol, 1.6 hexanediol, 1.3 butylene glycol, hydrogenated bisphenol, trimethylolpropane, trimethylol Examples thereof include polyhydric alcohols such as ethane, glycerin, pentaerythritol, and cyclohexanedimethanol, and alkylene oxides and epoxy resins of these, which can be used in any ratio.

During solution polymerization of acrylic resin, an organic solvent is often used for diluting alkyd resin. In that case, since non-aqueous organic solvents such as toluene, xylene, and mineral spirit have poor water dispersion stability, it is preferable to use hydrophilic organic solvents. The use of non-aqueous organic solvents should be limited to very small amounts.

Examples of hydrophilic organic solvents that can be used include alcohol solvents such as methanol, ethanol and butanol, ether solvents such as dimethyl ether and diethyl ether, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, ethyl cellosolve, Ethylene glycol solvents such as butyl cellosolve and cellosolve acetate, and propylene glycol solvents such as propylene glycol monobutyl ether. A known aqueous organic solvent such as a diethylene glycol-based solvent such as butyl carbitol may be used in any proportion.

When the resin obtained by the present invention is dispersed in water, it is desirable to neutralize a part or all of the carboxyl groups in the resin with a neutralizing agent, if necessary.
The pH after neutralization is preferably 6.5 to 9.5.
Examples of the neutralizing agent include inorganic alkalis such as potassium hydroxide and sodium hydroxide, ammonia, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, mono-n-propylamine, dimethyl-n-propylamine, monoethanolamine. , Diethanolamine, triethanolamine, N-methylethanolamine, N-aminoethylethanolamine, N-methyldiethanolamine, monoisopropanolamine, diisopropanolamine,
One or more selected from amines such as triisopropanolamine, NN-dimethylpropanolamine, and the like.

Examples of general emulsifiers and protective colloids used in the present invention include anionic emulsifiers such as sodium lauryl sulfate, sodium alkylbenzene sulfonate, sodium dioctyl sulfosuccinate, polyoxyethylene alkylphenyl ether sulfate, and alkyl picol chloride. , A cationic emulsifier such as alkyl trimethyl ammonium chloride, a nonionic emulsifier such as polyoxyethylene-polyoxypropylene block copolymer,
Further, water-soluble oligomers and emulsifiers having an ethylenically unsaturated double bond, so-called reactive emulsifiers, aqueous fibrin such as hydroxyethyl cellulose, carboxyethyl cellulose, and the like can be mentioned, and these can be appropriately selected and used.

The amount of these used should be limited to an extremely small amount, and if used in a large amount as in the conventional case, it is impossible to improve the alkali resistance, water resistance and substrate adhesion intended by the present invention. Conventionally, a general emulsifier and a protective colloid are used in a solid content of 1 in an aqueous dispersion of a nitrocellulose resin.
It was generally used in an amount of 5 to 10% with respect to 100 parts, but when the emulsifying apparatus of the present invention is used, the amount of the anionic or cationic emulsifier used is 1% or less, more preferably 0. It should be 5% or less, 3% or less for nonionic emulsifiers, and more preferably 1% or less. In the case of an acid group added when a hydrophilic group is contained, an acid value of 50 or more does not meet the gist of the present invention because it has various drawbacks as described above, and more preferably 30 or less. .

The resulting nitrocellulose resin solution is roughly emulsified by adding water, and then passed through the emulsifying apparatus of the present invention to be emulsified. The aqueous dispersion-type nitrocellulose-based resin of the present invention can be directly kneaded with various coloring pigments, extender pigments, etc., the dispersion stability of the blended liquid,
It has the characteristics of excellent mechanical stability and very few foaming problems.

The coating composition using the aqueous dispersion type nitrocellulose resin obtained according to the present invention can be applied by any method such as dip coating, shower coating, electrodeposition coating, brush coating, spray coating and roll coating. It is possible and can be applied to the surface of wood, paper, fibers, plastics, ceramics, inorganic cement substrates, ferrous, non-ferrous metals, etc. to give excellent performance.

[0035]

The present invention will be described in more detail based on the following examples, but the present invention is not limited to the technical idea thereof.
The present invention is not limited to these examples, and all ratios of respective components are based on weight unless otherwise specified.

[Production Example 1] (Production Example of Nitrocellulose Resin) 200 parts of soybean oil, 50 parts of glycerin and 0 and 15 parts of lithium hydroxide were added to a clean container in which nitrogen gas was refluxed at 250 ° C. with stirring. The temperature was raised to and held for 1 hour, 85 parts of glycerin and 200 parts of phthalic anhydride were charged, and the mixture was held at 230 ° C. for 6 hours and cooled to 130 ° C. Butyl cellosolve 20.
After 0 parts and 10 parts of triethylamine were added, the mixture was well stirred. A viscous resin liquid A having an acid value of 5 (solid content) was obtained. 100 parts of this resin liquid A and nitrocellulose LIG1 / 16 (I
(30% PA 30%) Asahi Kasei 45 parts were added and well stirred with Paint Saker, then 150 parts of ion-exchanged water was added and well stirred again with Paint Saker to obtain a preliminary dispersion liquid of resin and water.

PRODUCTION EXAMPLE 2 (Production Example of Nitrocellulose Resin) 234 parts of butyl cellosolve, 110 parts of n-butanol, 250 parts of styrene, 250 parts of 2-ethylhexyl methacrylate, 20 parts of methacrylic acid and 180 parts of methyl methacrylate in a clean container. Parts, 14 parts of perbutyl O, 20 parts of perbutyl Z, and 5 parts of lauryl mercaptan are added and gradually heated to 80 ° C. with stirring and held for 3 hours, and then 100 ° C.
The temperature is raised to and held for 8 hours and then cooled. 24 parts of triethylamine was added and stirred well. A viscous resin liquid B having an acid value of 20 (solid content) and a nonvolatile content of 65% was obtained.

[Production Example 3] (Production Example of Nitrocellulose Resin) In a clean container, 234 parts of butyl cellosolve, 110 parts of n-butanol, 250 parts of styrene, 250 parts of 2-ethylhexyl methacrylate, 20 parts of methacrylic acid and 180 parts of methyl methacrylate. Parts, 14 parts of perbutyl O, 20 parts of perbutyl Z, and 5 parts of lauryl mercaptan are added and gradually heated to 80 ° C. with stirring and held for 3 hours, and then 100 ° C.
The temperature is raised to and held for 8 hours and then cooled. 24 parts of triethylamine was added and stirred well. A viscous resin liquid C having an acid value of 20 (solid content) and a nonvolatile content of 65% was obtained.

[Production Example 4] (Production Example of Nitrocellulose Resin) In a clean container, 250 parts of butyl cellosolve, 170 parts of butyl carbitol, 100 parts of ethyl acrylate, 187 parts of n-butyl methacrylate, 48 parts of acrylic acid, dibutyl itako 64 parts of nate, 100 parts of methyl methacrylate
Parts, 7 parts of azobisisobutyronitrile, and 7 parts of benzoyl peroxide were added and gradually heated to 70 ° C. with stirring, and then held for 2 hours, then heated to 80 ° C. and held for 5 hours, and cooled to triethylamine. 51 g was added and stirred well. A viscous resin liquid D having an acid value of 53 (solid content) and a nonvolatile content of 55% was obtained.

Example 1 After adding 500 parts of ion-exchanged water to each 500 parts of the resin solution A and stirring the mixture, an emulsifier having a chamber connected to a disk having holes having an inner diameter of 100 μ, The mixed solution was introduced into a microfluidizer (manufactured by Microfluidic Co., Ltd.) with a pressurized compressor of 8 kg / cm ² , and the flow rate was 200 m / Sec, 5
The emulsion was dispersed and emulsified at a pressure of 00 Kg / cm ² .

The properties and storage stability of the resulting aqueous dispersion are shown in Table 1. [Examples 2 and 3] Resin solutions B and C were used instead of the resin solution A of Example 1, and the pressure when the solution passed through the flow path of the microfluidizer was changed to change the type of nitrocellulose. The same procedure as in Example 1 was carried out except that it was changed. The properties and storage stability of the resulting aqueous dispersion are shown in Table 1. Nitrocellulose used in Example 1 was LIG1 / 16
(IP30% WET) (trade name), Example 2 is HIG1
(IP30% WET) (trade name), Example 3 is HIG1
/ 4 (IP30% WET) (trade name), both manufactured by Asahi Kasei. In Example 3, 0.2 parts of the aqueous additive Neogen R (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added.

[0042]

[Table 1] [Comparative Examples 1, 2 and 3] The mixed liquid of Example 1 was passed through a Manton-Goulin colloid mill TYPE-15M (manton-Gorin Co., Ltd.) at 350 Kg / cm ² five times to disperse and emulsify it. The properties are as shown in Table 1, but the average particle size could not be measured due to insufficient dispersion. Further, when it was stored at room temperature for 1 week, the dispersion liquid was dispersed in two layers (Comparative Example 1).

The mixture was stirred in a TK-Automixer (made by Tokushu Kiki Co., Ltd.) at 10,000 rpm for 15 minutes.
Phase inversion did not emulsify (Comparative Example 2). Further, the mixed solution was treated with a static mixer (16 stages, manufactured by Noritake), but phase inversion emulsification was not performed (Comparative Example 3). The properties of the obtained aqueous dispersion are shown in Table 2.

[0044]

[Table 2] [Comparative Examples 4, 5, and 6] Manton-Gaulin Colloid Mill T was prepared by mixing resin solutions C, C, and D with ion-exchanged water.
YPE-15M (manton golin company) 300 kg /
cm ² 5 passes, static mixer (16 stages, Noritake made) 2 passes, TK automixer (made by special machine) 1
The resulting aqueous dispersion and storage stability were observed at 0000 rpm for 30 minutes, but no sedimentation was observed even after storage at room temperature for 3 months. In addition, Comparative Example 4 and Comparative Example 5
For the above, Neogen R (aqueous anionic emulsifier, manufactured by Dai-ichi Kogyo Seiyaku, trade name) and Emulgen 950 (aqueous anionic emulsifier, manufactured by Kao, trade name) were added when preparing the mixed solution.

[Application Example] Examples 1 to 3 and Comparative Examples 4 to 6
The resin dispersion obtained in step 1 was applied to a glass plate to form a clear coating film, which was dried for 1 day and then immersed in a 5% aqueous sodium hydroxide solution and 40 ° C. warm water for 24 hours to measure the coating film characteristics. The results are shown in Table 3.

[0046]

[Table 3] From Tables 1, 2 and 3, nitrocellulose resins having an acid value of 30 or less cannot be emulsified and dispersed by a conventional disperser such as a colloid mill and a static mixer, and nitrocellulose having an acid value of 30 or more. Although the system resin can be emulsified by a conventional disperser, the properties of the coating film are remarkably inferior, while the aqueous dispersion-type acrylic resin obtained by the production method of the present invention has excellent properties and storage stability. It is clear that the coating properties of the resin dispersion are also excellent.

[0047]

EFFECTS OF THE INVENTION The aqueous dispersion type nitrocellulose resin obtained by the production method of the present invention has excellent adhesion to various base materials and excellent water resistance and chemical resistance as in the case of the conventional solvent type. For this reason, it can be used not only for conventional aqueous dispersion type nitrocellulose resins but also for outdoor construction and automobile top coats, as well as other anticorrosion paints, paints for home appliances, paints for general industrial machines, and woodworking paints. It can be used in a wide range of applications such as various general-purpose paints, various primer paints, printing inks, and adhesives.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a chamber of the apparatus.

FIG. 2 is a cross-sectional view of a chamber of this device.

FIG. 3 is an assembled perspective view of a disk of a chamber of the device.

FIG. 4 is an assembled perspective view of the disk of the chamber of the present apparatus.

FIG. 5 is an assembled perspective view of the disk of the chamber of the apparatus.

[Explanation of symbols]

 1, 2 Suppression part 3, 3a, 3b, 4, 4a, 4b Disk 5, 6 Flat surface of disk 7 Disk connecting groove 8 Central part of disk connecting groove 9 Disk connecting groove 10 Disk hole

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Claims (2)

[Claims] 1. A pre-emulsified mixed solution is introduced under pressure into a channel in a chamber, and the mixed solution is caused to collide with a flat portion in the channel under high pressure, or the mixture is mixed in the channel under high pressure. A method for producing an aqueous dispersion-type nitrocellulose-based resin, which comprises emulsifying a pre-emulsified mixed liquid of water and a nitrocellulose-based resin with an apparatus for emulsifying by colliding liquids. 2. The pressure at the time of collision is 100 to 10,000 kg /
The method for producing an aqueous dispersion type nitrocellulose-based resin according to claim 1, wherein the method is within the cm ² .