JPS5912974A - Slurry composition - Google Patents

Abstract

PURPOSE:To prepare a novel slurry composition giving a coating film having higher film properties than the film of powder coating, without necessitating waste water treatment, and useful as a paint, ink, adhesive, etc., by dispersing powder coating in a vinyl oligomer having crosslinkable functional groups. CONSTITUTION:A thermosetting resin preferably based on an acrylic resin is added with a crosslinking agent, a pigment, a leveling agent, and if necessary, a crosslinking reaction catalyst, etc., and mixed in dry state. The mixture is molten and kneaded with an extruder, cooled, and pulverized to an average particle size of preferably 5-20mu to obtain powder coating. The objective slurry composition is obtained by adding the powder coating to a vinyl oligomer containing crosslinkable functional groups (preferably having a number-average molecular weight of 500-1,500), and dispersing homogeneously with a ball mill, etc. It is preferable to add a curing agent such as hexamethoxymethylmelamine, bisphenol A-glycidyl ether epoxy resin, etc. to the powder coating and/or the oligomer.

Description

[Detailed description of the invention] The present invention relates to novel and useful slurry compositions.

Slurry paint, which is a powder coating dispersed in water, is prepared using the i.v.
Not only does it have the advantage that it can be easily obtained by following the same equipment and method as for ordinary water-based paints without using any separate equipment, but it also has the advantage that it can be easily obtained by simply applying one coat, which is unique to powder paints. It also has the advantage of being able to produce thick coatings.

However, in order to obtain such a slurry paint, it is necessary to use a surfactant or a water-soluble resin to disperse the powder coating in water, and it is not always necessary to use the excellent coating performance of the powder coating used. There are many disadvantages, such as not being able to express it as it is, and the need for wastewater treatment.

However, in view of the various problems with conventional slurry paints, the present inventors have conducted intensive research and found that simply dispersing powder paints in specific oligomers can produce powder paints that are equivalent to or even better than powder paints. It goes without saying that it is possible to obtain a paint with the above coating performance.
The present invention was completed after coming to the conclusion that it is preferable from a pollution control point of view, since it does not even require wastewater treatment.

That is, the present invention provides a slurry composition comprising a powder coating dispersed in a vinyl oligomer having a crosslinkable functional group.

Here, the above-mentioned powder coating may be thermosetting or thermoplastic, but on the other hand, the above-mentioned vinyl oligomer cannot be crosslinked and cured when heated. is necessary.

Therefore, unless the vinyl oligomer itself is capable of self-crosslinking, a curing agent having a functional group reactive with the functional group present in the oligomer may also be present in the composition of the present invention. Therefore, it is recommended that the curing agent component be mixed in advance with the above-mentioned powder coating or vinyl oligomer as an essential component of the composition of the present invention. Both are necessary.

First, as the powder coating, both the well-known and commonly used thermosetting type and thermoplastic type can be used. Typical examples of the thermosetting type are acrylic, polyester, epotylene, and polyvinyl chloride. Alternatively, thermosetting resins, especially acrylic resins, are used because it is desirable that the powder coating has good compatibility with the vinyl oligomer when forming a coating film. Powder coatings based on these are preferred.

There are various types of crosslinking for heating and curing the powder coating, but firstly, when it is an acrylic type and is based on an acrylic copolymer having a hydroxyl group,
Typical crosslinking agents include block isocyanate compounds, melamine resins, and acid anhydrides; when based on acrylic copolymers with carboxyl groups, epoxy resins or oxazoline compounds are typical crosslinking agents. When the base is an acrylic copolymer having a glycidyl group, polyhydric carboxylic acid compounds or amine compounds are typical examples, and next, polyester resins having a C1 hydroxyl group as a base are used. When the crosslinking agent is based on a polyester resin having a carboxyl group, the typical crosslinking agent is a blocked isocyanate compound, melamine resin, or acid anhydride, and when the base is a polyester resin having a carboxyl group, an epoxy resin is a typical crosslinking agent. Furthermore, in the case of epoxy systems, typical crosslinking agents include amine compounds, polycarboxylic acid compounds, and acid anhydrides thereof.

In order to prepare the thermosetting powder coating It(al), known and commonly used methods can be applied as they are, but the most preferred method is to apply each base resin and crosslinking agent as described above,
In this method, pigments, flow-through chips, and, if necessary, crosslinking reaction catalysts are added and mixed in a dry manner, then melt-kneaded using an extruder or the like, cooled, and pulverized.

From the viewpoint of dispersion stability, the average particle diameter of the powder amount It(a) obtained in this manner is suitably 50 μm or less, preferably 5 to 20 μm.

On the other hand, the above-mentioned crosslinkable functional group-containing vinyl oligomer is at least -m of a vinyl thread having a functional group such as a hydroxyl group, a carboxyl group, a glycidyl group, a methylol group, an alkoxylalkyl group, an isocyanate group, or an amine group. or a copolymer of these monomers and a vinyl yarn material having no functional group. Typical functional group-containing vinyl monomers include β- Hydroxyethyl (meth)acrylate or β-hydroxypropyl (meth)acrylate, (meth)acrylic acid, itaconic acid or fumaric acid, or (β-methyl)glycidyl (meth)acrylate, as well as methylol (meth)acrylamide, butoxy There are methyl (meth)acrylamide or aminoethyl (meth)acrylate,
Typical functional group-free vinyl monomers include styrene, α-methylstyrene, tert-butylstyrene, alkyl (meth)acrylate, (meth)acrylonitrile, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, Examples include vinyl acetate or vinyl chloride.

The functional group-containing vinyl oligomer obtained by polymerizing the above monomers by a conventional method, most commonly by radical polymerization or cationic polymerization in the presence of a solvent, and then removing the solvent, is a slurry. In order to form a composition, it is necessary that the oligomer be liquid at room temperature. Therefore, the number average molecular weight of the oligomer is suitably 2,000 or less, preferably within the range of 500 to 1.500.

In order for the composition of the present invention to be thermally cured, as described above, if the crosslinkable functional group present in the functional group-containing vinyl oligomer is not a self-curable group,
It is necessary to use a curing agent that has a functional group that is reactive with this functional group, and therefore, in such cases, it is necessary that the composition of the present invention contains a curing agent component. The curing agent component can be mixed with either the oligomer or the powder coating, or both of these oligomers and the powder coating.

Typical examples of such curing agents include melamine resins such as hexamethoxymethylmelamine or butyl etherified melamine when the functional group in the vinyl oligomer is a hydroxyl group, or a methanol block of hexamethylene diisocyanate. There are blocked isocyanate compounds such as ε-caglolactam blocked compound, which is an adduct of 2 moles of isophorone diisocyanate and 1 mole of ethylene glycol, and when the functional group is a carboxyl group, glycidyl ether type epoxy of bisphenol A is used. There are resins and epoxy resins such as triglycidyl isocyanate, and when the functional group is a glycidyl group, there are polyhydric carboxylic acid compounds such as sebacic acid or dotecaniic acid, and when the functional group is an amino group, there are polyhydric carboxylic acid compounds such as bisphenol. Examples include glycidyl ether type epoxy resin A.

Of course, when the functional group is a methylol group or an alkoxymethyl group, vinyl oligomers containing such functional groups self-condense, so it is not necessarily necessary to add a curing agent. This does not in any way prevent the addition of melamine or the like.

The streaks 9 to 1 of the compositions of the present invention can be obtained by dispersing each of the above-mentioned powder coatings in a functional group-containing vinyl oligomer.Simply stirring may be used as the dispersion method; The smaller the diameter, the more time it takes for dispersion, and if the dispersion is poor, spots may occur in the resulting coating film, making it impossible to expect sufficient coating performance.

Therefore, it is preferable to completely disperse it using a ball mill, sand mill, or roll mill. Yes.

It is also possible to mix a pigment at this time to cause crosstalk.

Furthermore, a known and commonly used solvent, surfactant, leveling agent or antioxidant may be added to the composition of the present invention, if necessary.

The main use of the composition of the present invention thus obtained is as a paint, which can be applied by spray coating, dipping coating or roll coating.
After applying it by a known painting method such as coating, it may be crosslinked and cured by heating at 100 to 300°C for several tens of seconds to several hours.For other uses, it can be used as an ink, adhesive, pressure-sensitive adhesive, sealant, or It can be used as a floor waterproofing agent, and can also be used to mold electrical or electronic parts.

Next, the present invention will be explained in more detail with reference to Examples. In the following, parts and percentages are based on weight unless otherwise specified.

Example 1 25 parts of glycidyl methacrylate, 5 parts of β-methylglycidyl methacrylate, 40 parts of styrene, 1
A mixture consisting of 0 parts acrylonitrile, 20 parts methyl methacrylate, 3 parts azobisisobutyronitrile and 2 parts benzoyl peroxide was added to 100 parts xylene heated to 120° C. over a period of 6 hours. The mixture was added dropwise to the mixture, and the mixture was further maintained at the same temperature for 10 hours to obtain a resin solution.

Next, the temperature inside the pot was increased to 180℃, and the pressure was increased to 2m×H.
While gradually reducing the temperature to y, the temperature was raised each time and the pressure was reduced to remove the distilled solvent until the content in the resin reached 0.6%.

To 100 parts of the obtained acrylic copolymer resin, 7 parts of dodecanedioic acid, 0.5 parts of 2-ethylhexyl acrylate polymer (flow agent; number average molecular weight = 20,000) and titanium oxide were added. 43 parts were added and dry mixed in a mixer, then melt-kneaded at 100°C (residence time: about 1 minute) in a co-kneader PR-46J (extruder manufactured by Buss Co., Ltd.), and then transferred to a jet mill. The mixture was pulverized to obtain a thermosetting powder coating having an average particle size of 10 μm.

Thereafter, 100 parts of this powder coating was mixed with 95 parts of an oligomer (2-ethylhexyl acrylate/2-hydroxyethyl methacrylate)-80/20 (weight ratio) having a number average molecular weight of 800, and hexamethoxymethyl. Mixed in a mixture with 5 parts of melamine, dispersed in a ball mill, and then spray-painted on a zinc phosphate treated steel plate,
A coating film was obtained by baking at 200°C for 20 minutes.

The coating film thus obtained was excellent in appearance characteristics such as gloss and sharpness, and was also excellent in flexibility with an Erichsen value of 7 or more and impact resistance of 1 kp x 50 cm or more.

Example 2 In a flask at 110°C containing a mixed solvent of toluene/butyl acetate = 80/20 (weight ratio), 35
A mixture consisting of 1 part of β-hydroxyethyl methacrylate, 30 parts of methyl methacrylate, 35 parts of styrene, 5 parts of azopisisoputiloni) and 1 part of di-tert-butyl peroxide was added dropwise over 4 hours. The mixture was then maintained at the same temperature for an additional 15 hours to obtain a resin solution.

After that, the solvent was removed in the same manner as in Example 1, and then 40 parts of titanium white and 0.5 parts of cyanine blue were added thereto while maintaining the temperature at 180°C, and the mixture was mixed for 5 minutes. , and cooled to room temperature.

Next, to 100 parts of this premix, 10 parts of a blocked isocyanate prepared by blocking an adduct of 1 mol of trimethylolpropane and 3 mol of inphorone diisocyanate with methanol and 2-ethylhexyl Except for adding acrylate polymer (same as above),
A powder coating having an average particle size of 5 μm was obtained by processing in the same manner as in Example 1.

Thereafter, 100 parts of this powder coating was mixed with a number average molecular weight i, oo of stearyl acrylate/2-hydroxyethyl methacrylate/acrylic acid=80/19/1 (weight ratio).

85 parts of the oligomer, 14.8 parts of methanol-blocked hexamethylene diisocyanate, and 0.2 parts of dibutyltin dilaurate were mixed in a ball mill to obtain a slurry composition.

Next, this was spray-painted onto a zinc phosphate-treated steel plate, and 2
A coating film was obtained by baking at 00°C for 20 minutes.

The coating film obtained here had excellent appearance characteristics such as gloss and sharpness, and also had good bendability and excellent flexibility.

Example 6 A mixture consisting of 1.046 parts of neopentyl glycol, 119 parts of 1,4-cyclohexane dimetatool, 1.000 parts of dimethyl terephthalate, and 11 parts of zinc acetate was removed from the reaction system to remove the generated methanol. After reacting for 1 hour at 150°C and 2 hours at 210°C, 47 parts of trimethylolpropane, 800 parts of terephthalic acid and 1 part of diptyltin oxide were added.
．． 5 parts was added and heated at 210°C for 4 hours and then at 240°C for 10 hours to effect dehydration condensation.

Next, the temperature of the reaction mixture was lowered to 180°C, and 313 parts of trimellitic anhydride was added thereto, and the reaction was carried out at 180°C for 6 hours to produce a polyester resin with a softening point of 125°C and an acid value of 62. Obtained.

Then, for 55 parts of this polyester resin,
Example except that 45 parts of an epoxy resin (epoxy equivalent = 440, softening point = 99°C) obtained by reacting phthalic acid diglycidyl ester and 5,5-dimethylhydantoin was used. A powder coating was obtained in the same manner as in 1.

Next, 100 parts of this powder coating was mixed with 2-ethylhexyl acrylate/styrene/monobutylmaleny)=8
The mixture was mixed into a mixture of 100 parts of an oligomer having a number average molecular weight of 700 (0/10/10 (weight ratio) and 30 parts of titanium oxide) and mixed and dispersed in a ball mill to obtain a slurry composition.

Thereafter, a coating film was obtained in the same manner as in Example 1 except that this slurry composition was used.

Although the coating film obtained here is slightly inferior in sharpness, #1 has excellent smoothness, has an Erichsen value of 7 or more, and has excellent physical properties with impact resistance of 500.9 x 50 J'cm. Met.

Claims (1)

[Claims] A slurry composition, such as a powder coating, made by dispersing a vinyl oligomer having a crosslinkable functional group.