JP3355760B2 - Unsaturated polyester resin composition for electrostatic coating, paint, coating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dicyclopentadiene-based unsaturated polyester resin composition for electrostatic coating which is excellent in coating property, atomization property and bubble bleeding property immediately after coating on wood and the like. The present invention relates to articles, paints, and electrostatic coating methods.

[0002]

2. Description of the Related Art In recent years, even in the coating of furniture, sports goods, crafts and the like in the woodworking field of unsaturated polyester resin, since wood contains moisture, the efficiency has been improved.
Electrostatic coating is used to prevent loss of resin during coating. However, an unsaturated polyester resin excellent in electrostatic coating properties, that is, a mist state (atomization property) rich in airtightness and excellent in coating properties has not been obtained.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an unsaturated polyester resin composition for electrostatic coating, which is excellent in atomization property, coating property, bubble removal property and surface drying property (floating state of wax). An object of the present invention is to obtain a paint for electrostatic coating.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies on dicyclopentadiene-based unsaturated polyester resin compositions in order to solve the above-mentioned problems. An excellent dicyclopentadiene-based unsaturated polyester resin composition was found, and the present invention was completed.

That is, the present invention relates to dicyclopentadiene,
And α-β unsaturated polybasic acid or anhydride thereof (A-1)
And bifunctional alcohol, glycerin and trimethylol
With one or more trifunctional alcohols selected from propane
Mixtures of polyfunctional alcohols consisting of (A-2) from the resulting unsaturated polyester (A), becomes from a vinyl polymerizable monomer (B), the resin solids, to 64-fold 55 wt%
% And the viscosity of NK-2 cup (made by Iwata Coating Machine)
50 to 70 seconds at 25 ° C. and trifunctional alcohol
Is contained in the resin solid content by 2 to 8% by weight.
For electrostatic painting unsaturated polyester resin composition, paint及
And painting methods .

The unsaturated polyester (A) of the present invention comprises:
It may be obtained by reacting (A-1) dicyclopentadiene , an α-β unsaturated polybasic acid, or an anhydride thereof with a mixture of (A-2) a polyfunctional alcohol, and preferably dicyclopentadiene. and alpha-beta unsaturated polybasic acid or anhydride, e.g., maleic anhydride, maleic acid, full <br/> Ma Le acid, itaconic acid, dicyclopentadiene-maleic acid or fumaric reacted in advance citraconic acid Acids and the like.

The term "dicyclopentadiene maleic acid or fumaric acid" used herein has a dicyclopentadiene and a carboxyl group in the molecule. Usually, maleic anhydride is converted to maleic acid with water and then converted to 1 mole of maleic acid. The amount of 125 to 13 is about 1 mol of dicyclopentadiene.
It is obtained by synthesizing at 5 ° C. or forming a half ester of glycol and maleic anhydride and then adding dicyclopentadiene at 125 to 135 ° C.
Depending on the case, an α-β unsaturated dibasic acid may be further and / or additionally used. Next, a condensation reaction is carried out in the vicinity of 200 ° C. under an inert gas together with the following acid and alcohol components.

The saturated polybasic acid or anhydride thereof includes phthalic anhydride, phthalic acid, isophthalic acid, terephthalic acid,
Examples thereof include tetrahydrophthalic anhydride, hetic acid, adipic acid, and esters thereof. They may be used alone or in combination of two or more. In particular, to improve the weather resistance, hexahydroanhydride, 1,2-cyclohexanedicarboxylic acid,
1,3 cyclohexane dicarboxylic acid, 1,4 cyclohexane dicarboxylic acid and the like can be used.

Examples of the polyfunctional alcohol include bifunctional alcohols and trifunctional alcohols such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, and 1,4.
-Butanediol, 1,6-hexanediol, 1,4
-Cyclohexane dimethanol, polyoxypropylene diol having a molecular weight of up to 1000, polyoxyethylene diol, and the like.

[0010] Examples of the trifunctional alcohol of the present invention include glycerin and trimethylolpropane. The amount of the trifunctional alcohols are 2-8 wt% in the resin solid content, with the coating is improved by a branched structure, a resin solid content in the reaction -
Easy to balance viscosity. If it is more than 8% by weight, the compatibility with the polymerizable monomer will be poor, and if it is less than 2% by weight, the effect of the present invention will not be sufficient.

The unsaturated polyester resin of the present inventionComposition
Is the relationship between non-volatile content and viscosity, Not55-64 volatiles
amount%,Preferably it is 57-62% by weight and the viscosity is NK-
2 cups (made by Iwata Coating Machine) for 50-70 seconds
Lance is excellent for atomization, coating, and bubble removal
You. Resin with non-volatile content (resin solid content) lower than 55%set
AdultAfter coating and curing, add to dryness
The floating of the wax is not uniform and the surface condition is poor
Become. On the other hand, if it is higher than 64% by weight, the floating of the wax
Is good, but bubbles are poor and the surface condition is poor. Painting
NK-2 cup at 25 ° C (made by Iwata Coating Machine) 50
The required condition is up to 70 seconds.

The vinyl polymerizable monomer (B) used in the present invention has one or more polymerizable double bonds in the molecule, and is not particularly limited. Used in resins, for example, styrene, α-methylstyrene, chlorostyrene, dichlorostyrene, divinylbenzene, t-butylstyrene, vinyltoluene, vinyl acetate, diallyl phthalate, triallyl cyanurate, and further acrylate methacrylic acid Esters and the like, which include methyl (meth) acrylate, ethyl (meth) acrylate, (meth)
Butyl ethylene glycol dimethacrylate, diethylene glycol dimethacrylate triethylene glycol dimethacrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) Acrylate, dipentaerythritol hexa (meth) acrylate and the like can be mentioned. These vinyl polymerizable monomers (B) may be used in combination of two or more.

It is preferred to add a polymerization inhibitor to the resin composition of the present invention. Examples of the polymerization inhibitor include toluhydroquinone, hydroquinone, 1,4-naphthoquinone, parabenzoquinone, trihydroquinone, p-tert-butylcatechol. , 2,6-tert-butyl-4-methylphenol and the like. Also, it is 15-10
It can be added as needed in the range of 00 ppm.

In the present invention, a curing accelerator is usually used. As a curing accelerator, a metal compound is added as needed. Examples of such a metal compound include cobalt naphthonate, cobalt octonate, divalent acetylacetonate cobalt, potassium hexoate, zirconium naphthonate, and zirconium acetylacetate. Nath, vanadium naphthonate, vanadium octonate, vanadium acetylacetonate, vanadyl acetylacetonate, a curing accelerator of a metal compound generally used in unsaturated polyester resins such as lithium acetylacetonate may be used in combination with these. Good, and also other accelerators such as amine-based, phosphorus-containing compounds,
It may be combined with known accelerators such as β-diketones.

The addition amount of the curing accelerator is usually 0.1 to 3 parts by weight based on 100 parts by weight of the total amount of the unsaturated polyester and the polymerizable vinyl monomer. In the present invention, an amine accelerator is preferred. The curing accelerator may be added to the resin in advance, or may be added at the time of use.

The resin composition of the present invention is usually cured by adding a curing agent. The curing agent that can be added is an electron beam curing agent,
One or more types selected from thermosetting agents and the like. Examples of the electron beam curing agent include halogenated alkylbenzenes and disulfide compounds.

The thermosetting agent includes organic peroxides,
Diacyl peroxide, peroxyester, hydroperoxide, dialkyl peroxide, ketone peroxide, peroxyketal,
Known substances such as alkyl peresters and percarbonates are used, and specific examples include methyl ethyl ketone peroxide and benzoyl peroxide. These curing agents are appropriately selected depending on kneading conditions, curing temperature and the like.

The addition amount of these curing agents is preferably 0.1 to 4 parts by weight based on 100 parts by weight of the total amount of the unsaturated polyester and the polymerized vinyl monomer. The above curing agents may be used in combination of two or more.

Further, a pigment can be added as a paint when coloring is required. As the pigment, for example, zinc stearate, titanium white, zinc white, and various other organic and inorganic pigments can be added.

For use as a coating material, it is preferable to add a wax (C). However, in order to impart dryness, a so-called dryness-imparting polymer (D) is used instead of or in combination with wax. ) May be blended. As the paint for electrostatic coating, it is preferable to add the component (C) alone, or the components (C) and (D). The added amount is (A) +
Preferably, (C) is used with respect to 100 parts by weight of the component (B).
300 to 600 ppm of the component and 10 to 30 parts by weight of the component (D) are added.

The wax (C) of the present invention is, for example, a paraffin wax having a different melting point, and can be suitably used in an amount of preferably 100 to 1000 ppm, more preferably 300 to 700 ppm, according to the working temperature.

The air-drying-imparting polymer (D) used in the present invention refers to an air-drying component as an essential component (an allyl ether group-containing compound, Compounds containing unsaturated higher fatty acid groups, compounds containing tetrahydrofurfuryl groups, compounds containing benzyl ether groups, etc.) are referred to.

As a method for introducing an air-drying component into an unsaturated polyester or vinyl ester resin or the like as the above-mentioned polymer, the following method may be mentioned.

One of them is that the glycol component has -OC
This is a method in which a compound having an allyl ether group represented by H ₂ —CH ＝ CH ₂ is used in combination. Next, in the acid component,
In this method, a compound derived from a cycloaliphatic unsaturated polybasic acid or a derivative thereof is used in combination.

Further, there is a method in which a compound derived using dicyclopentadiene is used in combination.

Among these various methods, as the allyl ether group-containing compound, any known compounds can be used. Among them, ethylene glycol monoallyl can be used. ether,
Diethylene glycol monoallyl ether, triethylene glycol monoallyl ether, polyethylene glycol monoallyl ether, propylene glycol monoallyl ether, dipropylene glycol monoallyl ether, tripropylene glycol monoallyl ether or polypropylene glycol monoallyl ether,

Or 1,2-butylene glycol monoallyl ether, 1,3-butylene glycol monoallyl ether, hexylene glycol monoallyl ether,
Various kinds of polyhydric alcohols such as octylene glycol monoallyl ether, trimethylolpropane monoallyl ether, trimethylolpropane diallyl ether, glycerin monoallyl ether, glycerin diallyl ether, pentaerythritol monoallyl ether, and pentaerythritol triallyl ether Examples include allyl ether compounds and various allyl ether compounds having an oxirane ring such as allyl glycidyl ether.

Next, as other glycol components used in combination, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butynediol, 2-methylpropane-1 , 3-diol, neopentyl glycol, triethylene glycol, tetraethylene glycol, 1,5-pentanediol, 1,6
-Hexanediol, bisphenol A, hydrogenated bisphenol A, ethylene glycol carbonate, 2,2-di (4-hydroxypropoxydiphenyl) propane, etc., may be used alone or in combination of two or more.

Further, other oxides such as ethylene oxide and propylene oxide can be similarly used. Also, as part of the glycol component and the acid component,
Polycondensates such as polyethylene terephthalate can also be used.

Further, as mentioned above, only typical examples of compounds comprising various cycloaliphatic unsaturated polybasic acids or their derivatives are exemplified, and tetrahydrophthalic anhydride, endmethylene Tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, α-
Terhinene-maleic anhydride adduct, rosin or ester gum.

Further, when used in combination with these cycloaliphatic unsaturated polybasic acids or their derivatives,
As α, β-ethylenically unsaturated dibasic acids or acid anhydrides thereof, maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, chlormaleic acid are exemplified. Acid or esters thereof, and then, if only aromatic aromatic dibasic acids or their acid anhydrides are exemplified, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid , Nitrophthalic acid, halogenated phthalic anhydride or esters thereof, and the like.Furthermore, if only typical examples of aliphatic or alicyclic saturated dibasic acids are given, oxalic acid, malonic acid,
Examples thereof include succinic acid, adipic acid, sebacic acid, aceleic acid, glutaric acid, hexahydrophthalic anhydride and esters thereof, and each may be used alone or in combination of two or more.

Further, synthesized from glycol and acid,
Resins obtained by reacting terminal carboxyl groups of unsaturated alkyd resins with reactive monomers having a glycidyl group can also be used.

Glycidyl acrylate or glycidime methacrylate may be mentioned as only typical examples of the glycidyl group-containing reactive monomer.

Further, β-PM which is cis-3-methyl-4-cyclohexene-cis-1,2-dicarboxylic acid and its anhydride (hereinafter, these are abbreviated as β-PMAA).
An AA unit compound can also be used, but the compound refers to β-PMAA as described above, and these compounds are an adduct of trans-piperylene and maleic anhydride, or an adduct thereof. It is obtained by ring-opening the acid anhydride group in it.

Further, as a typical compound having dicyclopentanedienes, hydroxylated dicyclopentanedienes can be mentioned.

An unsaturated polyester resin containing no dicyclopentadiene may be blended as long as the relationship between the resin solid content and the viscosity described above is maintained. When the resin composition of the present invention is used as a coating, as an additive for further improving weather resistance as necessary, a benzophenone-based, benzotriazole-based, ultraviolet absorber such as a cyanoacrylate-based compound or a UV stabilizer, a hindered amine-based is used. And can be appropriately selected and used. An additive such as an ultraviolet absorber or finely divided silica may be added for imparting thixotropic properties.

The electrostatic coating is usually performed by a portable electrostatic coating machine or a fixed electrostatic coating machine, and is selected according to the shape of the object to be coated. In addition, atomization may be performed by electricity or by compressed air, which is also appropriately selected from working conditions.

As the electrostatic coating method, a paint containing the unsaturated polyester resin composition of the present invention is transported from a paint tank to a spray nozzle (discharge port) by an electrically insulating paint hose, and for example, a single plate with a plus electrode , Plywood, wood products (furniture, musical instruments, cabinets), decorative objects, and other coating objects, using a spray handgun with an electrostatic generator, etc.
The paint is atomized by compressed air supplied by an air hose, and negative electricity is applied to the paint particles to apply the paint particles to form a coating film.

[0039]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited to these Examples. Further, “parts” in the text indicates parts by weight.

EXAMPLE 1 251 parts of dicyclopentadiene, 190 parts of propylene glycol, 254 parts of diethylene glycol, and 34 parts of water were placed in a two-liter four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet, and a reflux condenser. Part, glycerin 69
And 600 parts of maleic anhydride, and the mixture was reacted at 125 ° C. for 3 hours while paying attention to heat generation. Then, the temperature was raised to 200 ° C. to continue the esterification reaction. After 6 hours, hydroquinone was added to 0.
After adding 1 part, resin solid content 60%, styrene monomer 4
The mixture was adjusted to 0% to obtain an unsaturated polyester resin composition having an NK-2 cup viscosity of 60 seconds.

Example 2 A reaction apparatus similar to that used in Example 1 was used to prepare dicyclopentadiene 72.
6 parts, 500 parts of maleic anhydride and 100 parts of water were charged.
The mixture was held at 125 ° C. for 3 hours while paying attention to heat generation, to synthesize dicyclopentadiene maleic acid. Next, 152 parts of propylene glycol and 64 parts of trimethylolpropane were added, reacted at 200 ° C. for 5 hours, and 0.15 parts of hydroquinone was added. A resin solid content of 58% and a styrene monomer of 42% were mixed to give an NK-2 cup viscosity of 6.
An unsaturated polyester resin composition having 0 seconds was obtained.

Example 3 To the resin obtained in Example 2 was blended 20% of an allyl ether type non-wax resin synthesized as follows. The NK-2 cup viscosity of this resin was 70 seconds.

(Synthesis of Allyl Ether-Modified Unsaturated Polyester) Propylene glycol 434 was added to the above reactor.
Parts, trimethylolpropane diallyl ether 257
And 588 parts of maleic anhydride, and reacted at 200 ° C. for 6 hours. 0.19 parts of hydroquinone was added and dissolved in 780 parts of a styrene monomer. This had a resin solid content of 60% and a viscosity of 2.9 poise.

Comparative Example 1 Using the reactor of Example 1, the resin without glycerin of Example 1 was synthesized. Dicyclopentadiene 251
, 190 parts of propylene glycol, 254 parts of diethylene glycol, 34 parts of water, and 490 parts of maleic anhydride, and reacted at 125 ° C for 3 hours. Next, the temperature was raised to 200 ° C., and after an esterification reaction for 7 hours, 0.12 parts of hydroquinone was added. This resin was dissolved in a styrene monomer and the viscosity of NK-2 cup was adjusted to 60 seconds, but the resin solid content was as high as 67%. By the way, when the resin solid content was adjusted to 60%, the viscosity was reduced to 40 seconds, which deviated from the target value.

Comparative Example 2 Dicyclopentadiene 7 was added to the same reactor as in Example 1.
26 parts, 500 parts of maleic anhydride and 100 parts of water were charged and reacted at 125 ° C. for 3 hours. Next, 207 parts of propylene glycol were charged and the temperature was raised to 200 ° C. to carry out an esterification reaction. React for 8 hours, add hydroquinone to 0.1
Added 5 parts. The NK-2 cup viscosity was adjusted to 60 seconds.
The resin solids content was as high as 68%.

[Evaluation Test] 100 parts of the synthetic resins of Examples 1 and 2 and Comparative Examples 1 and 2 were added to 0.2 parts of 6% cobalt naphthenate and 130 ° F. paraffin wax 0.07.
And 1 part of 55% methyl ethyl ketone peroxide. The resin of Example 3 was similarly blended except that no paraffin wax was added. Next, the plywood having a moisture content of 12% subjected to the sealer treatment was subjected to electrostatic coating (hand REA manufactured by Ransburg Industry) using a hand gun air spray. The evaluation method is performed visually,
The results are shown in Table 1.

[0047]

[Table 1] Table 1

[Evaluation Criteria] <Atomization> A: The paint coming out of the nozzle is fine mist-like particles.

X: The paint coming out of the nozzle has large particles, and the particle diameter is not uniform. <Coatability> :: The paint is applied at 30 g / meter ² or more.

×: less than 30 g / m ^{2 of} paint. <Bubble removal property> ：: Defoams within 3 minutes after coating. X: It takes more than 3 minutes after coating. <Coating State Observation> The presence or absence of tackiness was observed by touch (4 hours in Example 3 and 1 hour after that), and the surface smoothness (1 day after) was visually observed.

[0051]

According to the present invention, the trifunctional alcohol-modified dicyclopentadiene-based unsaturated polyester resin has an atomizing property,
It is possible to obtain an unsaturated polyester resin composition for electrostatic coating, a paint, and an electrostatic coating method which are excellent in coating property, bubble removal property and coating film state.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // (C08L 67/06 C08L 91:06 91:06 101: 00 101: 00) (56) References JP-A-56-34717 (JP, a) JP Akira 63-142012 (JP, a) JP Akira 51-17920 (JP, a) JP Akira 64-65177 (JP, a) (58 ) investigated the field (Int.Cl. ⁷ , DB name) C09D 5/46 C09D 167/00-167/08 C08L 67/00-67/08 C08G 63/52-63/58

Claims (3)

(57) [Claims] 1. A difunctional compound comprising: dicyclopentadiene, an α-β unsaturated polybasic acid or its anhydride (A-1),
And glycerin and trimethylolpropane
It from a mixture of polyfunctional alcohols consisting of one or more trifunctional alcohol (A-2) from the resulting unsaturated polyester (A) is a vinyl polymerizable monomer and (B)
The resin solid content is 55% by weight to 64% by weight;
K-2 cup (made by Iwata Coating Machine) Viscosity is 50 ~ at 25 ℃
70 seconds and trifunctional alcohol in resin solids
2 to 8% by weight of the unsaturated polyester resin composition for electrostatic coating. 2. The unsaturated poly for electrostatic coating according to claim 1.
A paint obtained by blending an ester resin composition, a wax (C) and / or an air-drying imparting polymer (D). 3. An electrostatic coating method comprising using the unsaturated polyester resin composition for electrostatic coating according to claim 1.