JPS5844705B2 - Hungtai Reiyo Base - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel resin composition for powder coating bases.

More specifically, the present invention relates to a resin composition that has excellent storage stability and is easily cured simply in the presence of air without the presence of a catalyst or curing agent to provide a coating film of good quality.

It has been known that a radical catalyst and a vinyl monomer that is solid at room temperature are added to an unsaturated polyester that is solid at room temperature to prepare a resin composition for a powder coating base.

In this resin composition, the monomer in it acts as a crosslinking agent, and a highly crosslinked cured coating film is formed through a curing reaction, but it may emit a characteristic odor during baking, or
It has the disadvantage of low storage stability.

Powder coatings are generally prepared by melt-kneading base resins, pigments, spreading agents, etc., pulverizing them, and sieving them, but when a catalyst is added, the kneading is carried out at temperatures far above the decomposition temperature of the catalyst. Since it must be carried out at a low temperature, the crosstalk temperature is limited.

As a result, the polyester resins that can be used are necessarily limited to those with a low melting point, and the selection range of the types and amounts of acids and alcohols used as raw materials for producing the polyester resins is limited.

Moreover, since the powder coating itself is based on a resin with a low melting point, it is inevitable that the powder coating itself will have a low softening point, and storage stability will tend to deteriorate. It becomes impossible to use additives as ingredients.

The present inventors have solved the drawbacks of such conventional resin compositions for powder coating bases containing catalysts, and have developed a resin composition that has good storage stability, can be used in combination with substances of any melting point, and is of high quality. In order to develop a resin composition that can form a coating film, we have conducted extensive research and found that by combining an unsaturated polyester that is solid at room temperature with a polyester that has a fulbornene ring, we can create a resin composition that does not require the addition of radical catalysts or vinyl monomers. However, the present inventors have discovered that the scale can be used as a base for powder coatings, and based on this knowledge, the present invention has been completed.

That is, the present invention provides a resin composition for a powder coating base comprising (4) an unsaturated polyester that is solid at room temperature (!: (B) a polyester having a norbornene ring).

This composition has the characteristic of being air curable, and will not cure if kneaded in a closed kneader or in an inert gas atmosphere.

The unsaturated polyester used as component (4) of the present invention is an unsaturated polyester that is solid at room temperature and has an ester unit derived from α, β-ethylenically unsaturated carboxylic acid or α-ethylenically unsaturated carboxylic acid in the molecule. It is a saturated polyester.

These include, for example, unsaturated dicarboxylic acids such as maleic anhydride, fumaric acid, itaconic acid, or combinations thereof with phthalic acid, isophthalic acid, terephthalic acid, naphthalene dicarboxylic acid, adipic acid, sebacic acid, dodecanedioic acid, trimellitic acid. A mixture of aliphatic saturated dicarboxylic acids or aromatic polycarboxylic acids such as ethylene glycol, propylene glycol, chrycerin, pentaerythritol, trimethylolpropane, butanediol, diethylene glycol, bis[4-[β-hydroxypropyranophenyl] - Produced by condensation with polyols such as fluoropane, bisphenol A.

In addition to the above-mentioned condensation components, monocarboxylic acids such as benzoic acid, p-oxybenzoic acid, acrylic acid, and methacrylic acid can be used in addition.

In addition, the polyester used as component (2) has a norbornene ring represented by the formula (R in the formula is a hydrogen atom or a methyl group) in either the main chain, side chain, or terminal part, This product has, for example, the general formula (R in the formula has the same meaning as above, R' is a hydrogen atom,
a component selected from norbornene derivatives represented by methyl group or ethyl group; benzoic acid, trimellitic acid,
Components selected from carboxylic acids such as fumaric acid and maleic anhydride, ethylene glycol, propylene glycol, chrycerin, pentaerydrift, trimethylolpropane, butanediol, diethylene glycol, bis(4,-(β- It is produced by condensing hydroxypropyranophenyl]-propane with a component selected from unapolyols such as bisphenol A.

The composition of the present invention is prepared by mixing the above-mentioned components (4) and (8) at a weight ratio in the range of 9:1 to 1:9, preferably 8:2 to 2:8, by a known method. be done.

For example, as a melt mixing method, co-kneader, twin-screw kneader
It is advantageous to use

Further, a solution mixing method, a polymerization mixing method, a mechanical mixing method, etc. can also be used.

Depending on the intended use, various pigments, flow agents, softeners, fillers, etc. can be added to the composition of the present invention while it is being melted.

Since this material does not undergo gelation at all during the crosstalk operation, it has the advantage that additives can be selected from a wide range.

When the composition of the invention is applied in the form of a thin film and heated in the presence of oxygen, curing proceeds rapidly to provide a coating film with excellent physical properties and appearance.

For example, when this composition is applied to a suitable surface by a conventional technique such as fluidized dipping or electrostatic spraying and heated to a temperature of about 130°C or higher, preferably 150 to 220°C, a coating film with excellent properties can be obtained. It will be done.

The resin composition for powder coating base of the present invention has good storage stability because it does not contain a catalyst or a curing agent, and does not cause gelation or agglomeration during kneading operations at high temperatures, and can be used at any softening temperature. Since resins and additives can be used in combination, there is an advantage that there is a wide range of paint performance options.

Furthermore, since the curing reaction proceeds simply in the presence of air without using a catalyst or curing agent, it is very advantageous in terms of cost.

Next, the present invention will be explained in more detail by way of examples.

Reference Example 1 194 parts by weight of dimethyl terephthalate, 68.2 parts by weight of ethylene glycol, and 89.6 parts by weight of propylene glycol were mixed and transesterified at 210°C for 3 hours, and then 116 parts by weight of fumaric acid was added and reacted. An unsaturated polyester resin having a melting point of 80° C. was prepared by the following steps.

Reference Example 2 194 parts by weight of dimethyl terephthalate and 136 parts by weight of ethylene glycol were mixed and transesterified at 210°C for 3 hours, then 49 parts by weight of maleic anhydride was added and dehydrated at 200°C for 2 hours. Make it react.

Next, ethylene glycol was distilled off at 200°C under a reduced pressure of 0.6 MHg for 1.5 hours to increase the degree of condensation, thereby preparing an unsaturated polyester resin with a melting point of 120°C.

Reference Example 3 Bis (254 parts by weight of β-hydroxydiethynoriterephthalate, 86.4 parts by weight of naphthalene dicarboxylic acid, 29.4 parts by weight of maleic anhydride, and pentaerythritol) 13.6
After mixing parts by weight and reacting at 200°C for 2 hours, ethylene glycol was distilled off under reduced pressure to proceed with polycondensation, thereby preparing an unsaturated polyester resin with a melting point of 147°C.

Reference Example 4 194 parts by weight of dimethyl terephthalate, 30.4 parts by weight of propylene glycol, and 111 parts by weight of ethylene glycol were mixed and transesterified at 220°C for 3 hours, and then 5-norbornene 2,3-dicarboxylic anhydride was mixed. 115 parts by weight of the compound, 41.5 parts by weight of isofucric acid, and 7.3 parts by weight of adipic acid were added, and the reaction was continued for 2 hours.

Next, ethylene glycol was distilled off under reduced pressure to prepare a polyester resin with a melting point of 133°C.

Reference Example 5 194 parts by weight of dimethyl terephthalate and 136 parts by weight of ethylene glycol were mixed and transesterified at 210°C for 3 hours, and then 82 parts by weight of 5-norbornene-2,3-dicarboxylic anhydride was added. The reaction was allowed to proceed for 2 hours.

Next, ethylene glycol was distilled off under reduced pressure to prepare a polyester resin with a melting point of 153°C.

Reference Example 6 254 parts by weight of bis(β-hydroxyethyl) terephthalate, 13.4 parts by weight of trimethylolpropane, and 45.6 parts by weight of 5-norbornene-2-methyl-2-carboxylic acid were mixed and heated at 210°C. A polyester resin having a melting point of 89° C. was prepared by reacting for 3.5 hours and then distilling off ethylene glycol under reduced pressure.

Reference example 7 Bis(β-hydroxyethyl) terephthalate 559z
z part, 148 parts by weight of 5-norbornene-2,3-dicarboxylic anhydride, 11.6 parts by weight of fumaric acid, and 1 part by weight of adipic acid.
A polyester resin having a melting point of 130°C was prepared by mixing 4.5 parts by weight of the mixture and reacting at 210°C for 2.5 hours, and then distilling off ethylene glycol under reduced pressure to increase the degree of condensation.

Example 1 30 parts by weight of the polyester resin prepared in Reference Example 1, 70 parts by weight of the polyester resin prepared in Reference Example 4, 33 parts by weight of rutile titanium oxide, and 1 part by weight of Modaflow were kneaded while melting using a Busco kneader PR46. did.

After cooling, it was pulverized using a micro panthane mill (manufactured by Hoiyo Iron Works) to prepare a powder of 150 mesh passes.

The resulting powder paint was applied electrostatically using a Landsberg electrostatic handgun, and baked at 200°C for 30 minutes in a furnace.
00,91/2) A coating film of 45 cm1 and a gloss of 89 was obtained.

Examples 2 to 6 Using the same method as in Example 1, powder coatings were prepared according to the formulations (parts by weight) shown in Table 1.

A coating film having the physical properties shown in Table 2 was obtained by electrostatic coating using the same method as in Example 1 and baking and curing.

Claims (1)

[Claims] 1 (4) A resin composition for a powder coating base comprising a polyester having a norbornene ring (with an unsaturated polyester that is solid at room temperature).