DE2359538A1 - POWDER-FORM COATING COMPOUNDS AND COATING COMPOUNDS - Google Patents

Description

PATENT LAWYERS

DR.-ING. BY KREISLER DR.-ING. SCHÖNWALD DR.-ING. TH. MEYER DR. FUES DIPL-CHEjM. ALEK VON KREISLER DIPL.-CHEM. CAROLA KELLER DR.-ING. KLDPSCH DIPL-ING. SELTING

COLOGNE 1, DEICHMANNHAUS

Cologne, November 28, 1973 AvK / Ax

Nippon Paint Co., Ltd. Osaka / Japan.

Powder paints and coating compounds

The invention relates to powdered and applied as a powder Paints that have excellent shelf life, have and made of a solid resin and a polyisocyanate compound containing at least two isocyanate groups If the solid resin is one with an isocyanate group reactive active hydrogen atom, e.g. in a hydroxyl group or in a primary or secondary Amino group contains j, is that obtained in powder form? Paints are heat-curable at a lower temperature and give paint films with excellent surface properties and excellent physical properties. ·

Various attempts have recently been made to prevent the evaporation of solvents from paints into the atmosphere in order to avoid air pollution. For example, a powder spray method developed j "in which contains a powdered paint d no volatile component or only a small Men.ce a volatile component" is brought about by electrostatic spraying, by coating in the fluidized bed ο "like _o to" When Harzkomponentan in such pulverfcr-

4 0 9 8 2 3/1034

2s359538

For paints, vinyl chloride resins, epoxy resins, thermosetting acrylic resins and the like are used. Further, thermosetting polyester resins, thermosetting acrylic-modified polyester resins, urethane resins, thermoplastic acrylic resins, thermoplastic polyester resins, thermoplastic acrylic-modified polyester resins, etc. are used. During application, the powdery paint is heated so that the resin component contained therein is melted and converted into a thin liquid state, whereby a closed and smooth paint film is formed. The formation of a paint film is thus greatly influenced by the thermal thinness of the resin in the powdery paint, that is, better paints can be formed with a higher thermal thinness of the resin. However, a higher thinness of the resin generally leads to considerable sticking and caking of the powder particles when they are stored for a long time or at a high temperature, so that the use of the resin is practically impossible. \

On the other hand, the use of polyurethane resins that are crosslinkable with isocyanates and have excellent weather resistance, resistance to chemicals and mechanical Have properties, very desirable. Resins of this type are used extensively in paints of the solution type used. Because of the high reactivity of the isocyanate group, it is usually combined in one Two-component system used, d, fa. a paint in the form of a solvent and a crosslinking agent become immediately mixed before use. Or the isocyanate will be in a one-component system, i.e. all isocyanate groups are previously with a phenol or the like. blocked, and after application and after baking, the isocyanate groups are unblocked so that they complete the networking.

. 4 0S823 / 1 034 ■ ■ - ■ ·

Powder paints containing an isocyanate group-crosslinkable urethane resin which is stable at normal temperature can also be prepared in the manner described above, that is, by mixing a completely blocked isocyanate compound with a solid resin containing an active hydrogen atom and grinding the mixture . In order to form a cured paint film from such a powdery paint, it must be heated to the dissociation temperature of the blocking agent. In the case of tolylene diisocyanate blocked with phenol, the dissociation temperature is usually 180 ^° C. or more. In the case of tolylene diisocyanate * which is blocked with an alcohol, the dissociation temperature is usually 200 ° C. or more. In order to ensure a sufficient degree of crosslinking, it is therefore necessary to heat the paint film to a very high temperature. Further, the removal of a blocking agent usually gives rise to a peculiar odor which causes environmental pollution and causes discoloration, pore formation, and the like. in the formed painting film. The usual heat treatment thus leads to a significant deterioration in the surface properties of the paint films formed and counteracts the keeping of the environment, which is a desired effect in powder painting processes.

In an effort to keep up with common powder paints recognized intolerance to the thin thermal fluid and the shelf life and that using a fully blocked isocyanate compound to eliminate the disadvantage that occurs as a crosslinking agent, it was found that powder particles, by dispersing a polyisocyanate compound having an isocyanate group contains, are obtained in a solid resin, hardly stick together or stick together if stored for a long time or at high temperature. It was also found

that this polyisocyanate compound even if it is in is dispersed in solid resins containing an active hydrogen atom, is so stable that no substantial Deterioration in physical properties of the paint films formed with these paints results. Since the polyisocyanate compound used in the present invention has an extremely low vapor pressure, it reacts they so hard with the one active hydrogen atom containing solid resin that the paint formed is storage-stable and the properties of the paint formed Paints are not significantly affected by this. Furthermore, this polyisocyanate compound has a considerable lower toxicity, so that a great technical advantage is undoubtedly obtained with it. Also is it is not necessary to use paints containing the solid resin containing an active hydrogen atom and this polyisocyanate compound contain, at as high a temperature as ordinary paints, which one completely blocked isocyanate compound as a crosslinking agent, to be heated to dissociate the blocking agent. This advantage has the consequence that a sufficient degree of crosslinking can be achieved at a lower temperature and further in that no blocking agent is released, no environmental pollution and physical pollution Properties of the formed paint films are not deteriorated. The invention resides in the foregoing Determinations are based.

Accordingly, the main subject of the invention is powdery and powder-based applications. Paints that are good have shelf life, are thermosetting at low temperatures and do not cause environmental pollution and form paint films with good surface finish.

The powder paints according to the invention contain (A) a solid resin and (B) a polyisocyanate-409823/1034

compound that has an average of two or more free isocyanate groups contains in the molecule.

The solid resins (A) can be converted into (C) solid resins containing a active. Hydrogen atom "in a hydroxyl group, for example or contain a primary or secondary amino group, that is reactive with isocyanate groups, and (D) solid resins that do not contain active hydrogen atoms contain, be subdivided. '

In order to ensure good heat storage stability of the powdered paints containing the solid resin (A) and "polyisocyanate compound (B) without deterioration in fluidity", components (A) and (B) are preferably used in a weight ratio of 99-13 to 30:70 . If the amount of component (B) below 1 wt _o - $ is, the influence on the storage stability is much lower. When the amount of the component (B) is more than 70% by weight, the thin liquidity when exposed to heat is lower and a smooth paint film is difficult to obtain using the obtained paint. ^:

When the solid resin (C) is partially or exclusively as Component (A) is used, components (B) and (C) are preferably used in a proportion which corresponds to 0.2 to 2 moles of the isocyanate group in the former to • 1 mole of the active hydrogen in the latter «

As components (A), for example, acrylic resins are suitable _s polyester resins, acrylic-modified polyester resins, epoxy s polyether resins, amino resins, polyvinyl chloride resins, polyamide resins j polybutadiene and petroleum resins ", are preferably resins having a Einfriertempsratur of not less than about 5 ° C _S in particular from about 5 ° up to 15O ⁰ C (the freezing temperature is measured according to the balance method) ο

409823 / 1Q3A

Components (C) are those with a number average the molecular weight of about 400 to 30,000 and a glass transition temperature of about 5 to 80 ° C are preferred

The powder paints according to the invention show good shelf life. When they are applied to substrates and baked, they exhibit good thermal properties Thin liquid on. When the component (A) is partially or composed entirely of component (C), paint films with excellent properties are obtained on baking educated.

Component (B) must be selected depending on the type and the glass transition temperature of component (A) so that it is well compatible with component (A) when it melts and does not impart any tackiness to the powder paint containing component (A). If the glass transition temperature of component (A) is below about 5 C, the resulting paints are often sticky and difficult to grind at room temperature. If component (A) consists partially or exclusively of component (C), components (C) with a glass ^{transition temperature above about 80 0} O lead to poor thermal flow properties under conventional baking conditions, so that no smooth paint films are formed.

Specific examples of suitable acrylic resins that can be used as component (A) include the polymers obtained by polymerizing one or more of the monomers mentioned below: unsaturated monomers containing hydroxyl groups (e.g. 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate and 2-hydroxyethyl acrylate), unsaturated acid amide monomers (e.g. acrylamide, N-methylolacrylamide and methacrylamide), unsaturated monomeric carboxylic acids (e.g. acrylic acid, methacrylic acid, itaconic acid and crotonic acid), unsaturated monomeric acid anhydrides (ζ.B ₀ itaconic anhydride and maleic anhydride),

'■ ". 409823/1 034

Glycidyl moriomers (e.g. glycidyl acrylate and glycidyl methacrylate), Acrylic acid esters (e.g. ethyl acrylate, n-butyl acrylate and 2-ethylhexyl acrylate), methacrylic acid esters (e.g. methyl methacrylate, n-lauryl methacrylate and isobutyl methacrylate), Maleic acid esters (e.g. dihutyl maleate and diethyl maleate), fumaric acid esters (e.g. dibutyl fumarate and Diethyl fumarate), styrene and its derivatives (e.g. a-methylstyrene, ß-chlorostyrene ·, oc ^ -bromostyrene and p-bromostyrene) and nitriles (e.g. acrylonitrile * methacrylonitrile and ethylacrylonitrile). .

Acrylic resins which have a number average molecular weight of about 1,000 to 30,000 and contain about 1 χ 10 "^" to 30 χ 10 · ο1 active hydrogen atoms / g are preferred. If the number average molecular weight is below about 1000 or the active hydrogen atom content: below about Ί χ ΐθ ~ .Mol / g, insufficient crosslinking takes place in the paint film formed from a paint containing such an acrylic resin. Furthermore, this paint film does not have good physical properties. When the number average molecular weight is over about 3000Ό, the thermal flow properties of the paint films become poor. If the content of active hydrogen atoms is more than about 30 10 mol / g, the crosslinking proceeds excessively quickly, so that the surface quality of the paint film is greatly impaired. ^: - ·

More suitable as specific examples. Polyester resins are the reaction products of one or more types of polycarboxylic acids such as saturated aliphatic carboxylic acids (e.g. oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid and isosebacic acid) and aromatic carboxylic acids (e.g. phthalic acid, isophthalic acid and their anhydric acid and terephthalic acid) several of the following polyhydric alcohols mentioned as examples s Äthylenglykoljf 1 _S 2-Propylen-

4098 23/1034

glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,4-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, 1,3-hexanediol, 2,3-hexanediol, 2,4-hexanediol, 2,5-hexanediol, 3,4-hexanediol, 1,7-heptanediol, 1,6-heptanediol, 1,5-heptanediol, 1,4-heptanediol, 1,3-heptanediol, 2,3-heptanediol, 2,4-heptanediol, 2,5-heptanediol, 2,2-I) imetbyl-1,3-propanediol (Neopentyl glycol), 2,2-diethyl ~ 1,3-propanediol, 2-ethyl-2-bu1; yl-1,3-propanediol, 2,4-cyclohexanedimethylol, iDrimethylolpropane and glycerin.

The polyester resins can optionally be modified with customary modifying agents. Suitable modifying agents are, for example, unsaturated aliphatic carboxylic acids (e.g. maleic acid, fumaric acid, itaconic acid, citraconic acid and linoleic acid) or their anhydrides (e.g. maleic anhydride), higher unsaturated aliphatic carboxylic acids, natural oils and oils (e.g. linseed oil, sardine oil, dehydrated castor oil , soybean oil, cottonseed oil, castor oil and palm oil), synthetic oils or fats and from the hydrolysates \ these oils and fats fatty acids obtained. j

Polyester resins with a number average molecular weight of about 500 to 5000 and a hydroxyl group content of about 3 × 10 "* ⁴ " to 45 × 10 mol / g are preferred. If the number average molecular weight is less than about 500 or the hydroxyl group content is less than about 3 × 10 10 mol / g, the crosslinking of the paint film is insufficient and the physical properties are poor. If the number average molecular weight is more than about 5000, the thermal flow behavior is poor. If the hydroxyl group content is above about 45 χ 10 mol / g, the paint films have a poor surface quality,

Suitable acrylic-modified polyester resins are resins by grafting an ethylenically unsaturated monomer and / or an acrylic resin onto the polyester

T TO "98 ~ 237 H) 3Ä"

resin can be obtained in a conventional manner by polymerization, condensation, addition, chain transfer reactions and / or the like. Acrylic-modified polyester resins of this type which have a number average molecular weight of about 500 to 20,000 and about 3 χ ΙΟ " ⁴ " to 45 × 10 "" ⁴ "mol active hydrogen atoms / g are preferred, if the number average molecular weight and the content of active hydrogen atoms are within these - ranges, the formation of well crosslinked paint films with good physical properties is guaranteed.

Polycondensates, for example, are suitable as epoxy resins of bisphenol A and epichlorohydrin, polyfunctional Epoxy compounds obtained by condensation of Novolakη with epichlorohydrin, epoxy compounds with polyether chain and alicyclic epoxy compounds. Examples suitable amino resins are the urea resins, melamine resins and guanamine resins, suitable as polyether resins, for example the addition products of alkylene oxides, e.g. ethylene oxide and propylene oxide, with low molecular weight polyols, e.g. ethylene glycol, glycerine, trimethylol propane and pentaerythritol. For the advantageous production of resin compositions crosslinkable with isocyanates suitably epoxy resins with a number average molecular weight of about 400 to 4000 or polyether resins with a number average molecular weight of from about 3,000 to 3,000. These resins are used in such Amount used that the sum of the number of hydroxyl groups in one molecule of the resin and the number of free isocyanate groups in one molecule of the polyisocyanate compound are not less than 5. In the case of the amino resins, it will be useful those having a number average molecular weight of about 400 to 2000 are used in an amount such that the Sum of the number of primary and secondary amino groups and hydroxyl groups in one molecule of the resin and the number

free isocyanate groups in a molecule of the polyisocyanate compound is not less than 5.

As the component (B) are preferably Polyisocyanatver- "used compounds which are solid at room temperature (eg, 5 to 30 ⁰ C) determined to cause a reaction between the free isocyanate groups and the active hydrogens to prevent as used as component (A) solid resin .

These polyisocyanate compounds can be prepared by converting polyisocyanates, for example diisocyanates or Iriisocyanates (for example hexamethylene diisocyanate, ethylene diisooyanate, propylene diisocyanate, tetramethylene diisocyanate, decamethylene diisocyanate, triphenylmethane triisocyanate, 4 _J 4 ^I -A * tbylenebiscyclohexyl isocyanate, 4,4'-methyl-bis-cyclohexylene isocyanate, 4,4'-methyl-cyclohexylene isocyanate, bis'cyclohexylene isocyanate. COjU -'-diisocyanate-1,3-dimethylbenzene, phenylene diisocyanate, lysine diisocyanate methyl ester, isophorone diisocyanate, trimethylhexamethylene diisocyanate, diphenylmethane-4,4'-diisocyanate, 3 »3'-dimethyldiphenylmethane-4,4'-diisocyanate) into a biuret structure or an aluminum structure. The polyisocyanate compounds can also be prepared by reacting one or more of the polyisocyanates mentioned and / or the polyisocyanate compounds mentioned having a biuret or allophanate structure with one or more chain extenders to form polyisocyanate compounds with an average of two or more free isocyanate groups in the molecule. Examples of suitable chain extenders are: polyhydric alcohols and polycarboxylic acids, as used in the production of the above-mentioned polyester resins, substituted and unsubstituted diamines (e.g. ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, octamethylenediamine, decamethylenediamine, p-xylylenediamine, -Diisobutylhexamethylenediamine, Ιί, ϋί - diethy! Hexamethylenediamine, K-isobutylhexamethylenediamine and N-benzy! Hexamethylenediamine), water and amino alcohols <,

409823/1034

Preference is given to polyisocyanate compounds which are obtained by reacting the abovementioned reactants in an equivalent ratio of the free isocyanate groups to the active hydrogen atoms in the chain extender of more than 1 (expedient / at least 1.5 and not more than 10) in the presence or absence of an inert solvent (e.g. butyl acetate , Toluene and methyl ethyl ketone) with or without a suitable basic catalyst or metal catalyst (e.g. trietbylamine, N-methylmorpholine, dibutyltin dilaurate and tin (II.) Chloride) at a temperature from room temperature to 2GO ⁰ C (expediently from 50 to 160 ⁰ C) getting produced. When the chain extender contains impurities in a large amount, by-products are generated and the physical properties of the paint films produced are considerably deteriorated. For this reason, the chain extender is expediently purified beforehand in the customary manner, for example by distillation, extraction or adsorption.

The reaction product obtained in this way can iη certain cases unreacted polyisocyanates and / or Contain oligomers and as such or after removal the unreacted polyisocyanates and the oligomers in the usual way, e.g. by distillation, extraction or adsorption. After purification in the manner described, the product obtained can be used alone or used in combination.

The powder paints according to the invention which contain components (A) and (B) can be used for the production of ■ -. Sheets, foils, iOlien, artificial leather, etc. are used; however, they are particularly beneficial as Powder paints. You can do this alone or used in admixture with one or more additives commonly used in the paint field be used. Examples of such additives are called: reactive compounds (e.g. aromatic

409823/1034

Polyamines, aliphatic polyamines, polycarboxylic acids and their anhydrides, polycarboxylic acid, dicyandiamide, BF ^ -Aminkomplexverbindungen completely "blocked cyanates compounds), pigments (such as TiO _2, FeO, silica, CaCO ,, basophilic, carbon black and phthalocyanine blue), plasticizers, ( e.g. dibutyl phthalate and dioctyl phthalate), cellulose derivatives (e.g. cellulose acetobutyrate, methoxy cellulose and ethoxy cellulose), anion-active surfactants (e.g. fatty acid salts and higher alcohol sulfates), non-ionic surface-active compounds (e.g. ammoniacal ammonium), quaternary surfactants (e.g. e.g. silicone resins and acrylic resins) and crosslinking catalysts for curing at low temperatures (e.g. triethylamine and dibutyltin dilaurate)

The powder paints according to the invention can by Uniform mixing of the ingredients in the usual way, e.g. in the dry or semi-dry state or as Melt, with the formation of a uniform dispersion. This uniform dispersion will then ground to form the powder paint.

The powder paint can be applied to the surfaces to be coated by customary application methods, for example by electrostatic powder spraying or by application in a fluidized bed and subsequent baking, which generally takes place at a temperature of 140 to 240 C for a time of 5 to 60 minutes, with the formation of good paint films be applied. In resin compositions which can be crosslinked with isocyanate groups are obtained by baking at relatively low temperatures, for example below ürethanharze of 200 ⁰ C with excellent surface finish. Since no blocking agent is released during stoving, when the mixtures according to the invention are used as

Paints do not pollute the environment. . 409823/1034

Practical and currently preferred embodiments of the Invention are described in the following examples in which the parts and percentages are by weight relate. ~

example 1 1-1) Preparation of the polyisocyanate compound

444.4 parts of isophorone diisocyanate and 62 parts of ethylene glycol are placed in a flask equipped with a reflux condenser, thermometer, nitrogen inlet and stirrer. After the air has been displaced by nitrogen, the reaction is carried out for 24 hours at 90 to 100 ^° C. “The product is colorless, transparent and solid at room temperature and contains 39.5 × 10 mol of free isocyanate groups per gram. ι

1.-2) Preparation of paint ·. ·

To a mixture of 350 parts of an acrylic resin (consisting of methyl methacrylate, styrene, isobutyl methacrylate, n-butyl methacrylate, glycidyl methacrylate and 2-hydroxyethyl methacrylate; glycidyl group content 10.6 χ 10 mol / g; hydroxyl group content 2 10 mol / g; number average molecular weight 6000; glass transition temperature of 50 ⁰ C), 37.5 parts of sebacic acid, 100 parts of titanium dioxide (rutile), and 5 parts of a leveling agent ( "Modaflow", Monsanto Co _0, Ltd. "), 25 parts given in the section 1-1" polyisocyanate prepared. The mixture is mixed as a melt in an extruder, ground and passed through a sieve with a mesh size of 149 yes , a powder paint (hereinafter referred to as ^W 1-A ") being obtained. ^: "" - ■ ·.

For comparison, a mixture of the same acrylic resin is used with sebacic acid, rutile and leveling agent "Modaflow" in treated in the same manner to obtain powder paint hereinafter referred to as "V-B".

409823/1034

1-3) test . .

The powder coating material ¹ MA "and" 1-B "are applied with an electrostatic spray device iron panels and baked 30 minutes at 200 ⁰ C. The results of the tests of the paint films are shown in Table 1. Glued After storage for 7 days at 4O ⁰ C and strongly cakes the powder paint "1-B" and is then unusable for practical use, while the powder paint "1-A" remains unchanged and can be used for making paint films having substantially the same properties as the paint films that have been made with the paint before storage.

- Table 1 1-B Remarks Powder painting
middle T-A immediate
cash after
Manuf
lung Test time right away
later
position Mirror reflection
60 ° shine 89 # Well smoothness Well 20 cm DuPont Schlas Impact resistance 20 cm

hardness

strength test; Height of fall of the falling weight (500 g, 12.7 mm)

Sward swing value; .Glass plate 58; - polymethyl methacrylate plate 23.

Example 2

2-1) Preparation of a blocked polyisocyanate compound 253.2 parts of the polyisocyanate compound prepared according to Example 1 and 94 parts of phenol are reacted for 3 to 8 hours at 130 to 140 ⁰ C. After the free isocyanate groups have been blocked completely, the temperature is lowered. A yellowish brown, transparent, at

409823/1 034

Room temperature solid product is obtained / ',

2-2) Making a. Paint .

A mixture of 155 parts of the Folyisoc.yanatverbindungen produced according to Example 2-1 and 345 parts of a polyester resin (consisting of isophthalic acid, neopentylglycoT and glycerol; hydroxyl group content 17.7 x 10 mol / gj number average molecular weight 1200; freezing temperature 5O ⁰ C) is by Mixing in the molten state made in an extruder and ground. The powder is passed through a sieve of 149 -JU mesh to obtain a powder paint (hereinafter referred to as ^rt 2-A "). J

Separately from this, 200 parts of titanium dioxide (rutile) are added to the aforementioned mixture. The ingredients are melt mixed and ground to obtain a powder paint (hereinafter referred to as "2-B"). ■. . y. · ■. . - \

For comparison, a mixture of 190 parts of the blocked polyisocyanate compound prepared in Example 2-1) and 310 parts of the above polyester resin is made into a powder paint (hereinafter referred to as "2-C ^u ) in the same manner.

Separately, 200 parts of titanium dioxide (rutile) are added to the aforementioned mixture. The ingredients are melt mixed and ground to obtain a powder paint (hereinafter referred to as "2-D"). ^:

2-3) "test ;

The powder paint composition "2-A" and ^If 2-C "are respectively with an electrostatic spray device Zinnbleohe applied and 30 minutes at 16Q ° C, 180 ° C, 200 ⁰ C 220 ⁰ G ■ '-" burned. The paint films formed are extracted for 5 hours in a Soxhlet Extraktormit Acetö ^n. Which he-"-

Average proportions of the insoluble material in weight percent are shown graphically in FIG. 1 as a function of the stoving temperature. Curve 1 shows the results for powder paint "2-A" and curve 2 shows the results for powder paint ^M 2-C ". The figure shows that the paint produced according to the invention can be baked at a lower temperature than the comparative paint i

The powder paint composition "2-B" and "2-D" are applied with an electrostatic spray device iron sheets and or 30 minutes at 18O ⁰ C, 30 minutes at 200 ⁰ C baked. In addition, the powder paint "2-B" is applied to an iron plate after being stored for 6 months at room temperature under the same conditions, and then baked. The results of the tests on the paint films are shown in Table 2.

Table 2

Powder
stroked
middle· 2 B 2-e -2-D, Remarks assignment Immediately
after
Herste 1-r
lung ' To
storage
for 6
months Immediately .
after
Manuf
lung shine 88 # 90 ^ Mirror re ^ exion
60 ° Pores no no numerous Discoloration
exercise no
» no strength
Yellowing Blow
firm
speed 25 cm 25 cm 25 cm DuPont impact
fitness test;
Height of fall
weight. (500 g,
12.7 mm)

hardness

35

35

Sward swing mechanism; Glass plate 58; Polyethylene methacrylate sheet 23

In acetone
more insoluble
Proportion 95.0

92.0 93.5

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ches material

As Table 2 shows, the paint according to the invention has good storage stability, and that formed therewith Paint films have excellent gloss, durability against discoloration and no pores. .

. Example 3

3-1) Preparation of the polyisocyanate compound: 212 parts of lysine diisocyanate methyl ester and 114 parts of purified bisphenol A are placed in a flask. The reaction is carried out under the conditions mentioned in Example 1. The product obtained is a pale yellow, transparent resin that is solid at room temperature,

-4 that has a content of free isocyanate groups of 30.7x10

Mol / g has. ·.

3-2) Preparation of the paint In the manner described in Example 2, a powder paint of 183.5 parts of the according to. Example 3-1) prepared polyisocyanate compound, 316.5 parts of the same polyester resin as in Example 2 and 175 parts of titanium dioxide (rutile). .

3-3) test

The according to Example 3-2) powder paint prepared is applied with an electrostatic spray device on an iron plate and baked for 30 minutes at 180 ⁰ C, with one-porous elastic paint film is obtained with excellent gloss. The results of the tests on the paint film are shown in Table 3.

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Table 3

assignment Immediately after Her
position After storage ^ for
3 months shine $ 86 $ 87 Pores no no Discoloration no no Impact resistant
speed 25 cm 25 cm hardness 34 34 In ^A ceton un
soluble at
part 88.0 # 87.5 $

The tests were based on those described in Example 2 " Way made.

Example 4

4-1) Preparation of the polyisocyanate compound In a flask are placed 250.2 parts of dipnenylmethane-4,4'-diisocyanate, 31 parts of purified ethylene glycol and 281.2 parts of butyl acetate. After displacing the air with nitrogen, the reaction is carried out for 24 hours at 120 ⁰ C 100'bis. If the butyl acetate is removed from the reaction mixture under reduced pressure, a white powdery substance is obtained which has a content of free isocyanate groups of 35.6 10 mol / g "

4-2) Preparation of the paint In the manner described in Example 2, a powder paint is made from 166.5 parts of the polyisocyanate compound prepared according to Example 4-1), 333.5 parts of the same polyester resin as in Example 2 and 175 parts of titanium dioxide (rutile) manufactured.

4-3) test

The according to Example 4-2) powder paint prepared is applied with an electrostatic spray device on an iron plate and baked for 30 minutes at 180 ⁰ C, wherein a non-porous elastic paint film

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excellent gloss and excellent color stability is obtained. Even after storage for 3 months at room temperature can make good paint films with the powder paint getting produced.

■ Example 5 5-i) Preparation of the paint

In the manner described in Example 1, a powder paint (hereinafter referred to as "5-A") of 126.6 parts of the polyisocyanate compound prepared according to Example 1 and 400 parts of acrylic resin ¹ (consisting of methyl methacrylate, styrene, n-butyl acrylate and 2 -Hydroxy-

—4 / ethyl methacrylate; Hydroxyl group content 12.5 x 10 mol / g; Number average molecular weight 5000; Freezing temperature 55 ° C). '- ".: -

Separately from this are 131.6 parts of lithium dioxide (rutile) added to the above mixture. The parts will be as. Melt mixed. The mixture is ground, being a powder paint (hereinafter referred to as "5-B" designated) is obtained.

For comparison, a powder paint (hereinafter referred to as "5-C") from 173.6 parts of the example 2 (2-1) prepared blocked polyisocyanate compound and 400 parts of the above-mentioned acrylic resin. . .. ...

Separately from this, 131.6 parts of 5-titanium dioxide are added. (Rutile) added to the above mixture. The ingredients will mixed as a melt. The mixture is ground, whereby a powder paint (hereinafter referred to as "5-D") is obtained. . ;

5-2) test ^; '-

The powder paint "5-A" and "5-C" are applied with an electrostatic spray device Zinnbleche and 30 minutes at 160 ⁰ C 180 ⁰ C, 200 C ^{0 0} C bzw.220

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The paint films formed are baked for 5 hours extracted in a Soxhlet extractor with acetone. The determined proportions of the insoluble material in wt .- ^ are shown graphically in Fig. 2 as a function of the burn-in time. Curve 3 represents the results for the powder paint "5-A" and the curve 4 the result Be for the powder paint "5-C". Fig.2 shows that the paint according to the invention is baked at a lower temperature than the comparative paint can be.

The powder paint "5-B" and "5-D" are applied with an electrostatic spray device iron panels and baked 30 minutes at 180 ⁰ C and 30 minutes at 200 ⁰ C. Furthermore, after storage for 3 months at room temperature under the same conditions, the powder paint "5-B" is applied to an iron plate and then baked ^{at 180 ° C. for 30 minutes.} The results of the tests on the paint films are shown in Table 4 below.

Table 4 5-C 5-d; Powder painting
middle 5-B According to location
tion for
3 months Immediately
later
position assignment Immediately
later
position $ 84 $ 86 shine $ 86 no _, numerous Pores no no strength
Yellowing Discoloration no 25 cm 20 cm Impact resistance 20 cm 35 34 hardness 34

Part insoluble in acetone 92,

92.75t

The tests were carried out in the manner described in Example 2.

409823 / 10ΓΑ

Claims (1)

Claims 1. Powder-like paints, consisting of at least one solid resin and at least one polyisocyanate compound, which contains on average at least two isocyanate groups in the molecule. 2. Powdered paints according to claim 1, characterized characterized in that the weight ratio of solid resin to polyisocyanate compound is in the range of 99: 1 to 30:70 lies. 3. Powdered paints according to claims 1 and 2, characterized in that the solid resin has a glass transition temperature ^{of not less than about 5 ° C.} 4. Powder paint according to claim 1 to 3, characterized in that the solid resin has a glass transition temperature of ⁰ C to 150 j5. ' 5 * Powdered paints according to claims 1 to 4, characterized in that the polyisocyanate compound is solid at room temperature. · 6..Powder-like paints according to claim 1 to 5, characterized in that, as the polyisocyanate compound, it is an addition product of a diisocyanate or triisocyanate with a chain extender that has two or more contains active hydrogen atoms. 7. Powdered paints according to claim 1 to 5, characterized in that it is used as a polyisocyanate compound a polyisocyanate compound derived from a diisocyanate or triisocyanate and having a biuret or allophanate structure contain. 409-823 / 1 034 8. Powdered paints according to claim 1 to 6, characterized in that they are used as a polyisocyanate compound an addition product of a polyisocyanate compound derived from a diisocyanate or triisocyanate with a biuret or allophanate structure with a chain extender containing two or more active hydrogen atoms contain. 9. Powdery paints according to claim 1 to 6, characterized in that they contain as the polyisocyanate compound the product obtained by reacting a Diisocyanate or triisocyanate or a polyisocyanate compound derived therefrom with a biuret or allophanate structure with a chain extender containing two or more active hydrogen atoms in an equivalent ratio the free isocyanate groups of the former reactant to the active hydrogen atoms in the latter reactant produced by more than 1 has been. 10. Powdered paints according to claim 9, characterized in that the reaction to form the polyisocyanate compound with an equivalent ratio of the free isocyanate groups to the active hydrogen atoms from 1.5 * 1 to 10: 1 has been carried out. 11. Powdered paints according to claim 1, characterized in that they contain solid resins which a contain active hydrogen atom. 12. Powdered paints according to claim 1 and 11, characterized in that they are solid resins with a Freezing temperature of about 5 to 8o ° C included. 15. Powder-shaped paints according to claim 1, 11 and 12, characterized in that they are solid resins acrylic resins having a number average molecular weight of 1000 to 50,000 and / or a content of active hydrogen atoms -4 -4 from 1 χ 10 to JO χ 10 mol / g. 409823/1034. j ■ ■ - 23 - j 14. Powdered paints according to claim 1, 11 and 12, j ■ characterized in that they are polyester resins as solid resins. resins with a number average molecular weight of 500 to 5000 and / or a content of active hydrogen _4 _4 - ■■ "■■■ Atoms from 3 χ 10 to 45 χ 10 mol / g contain. 15. Powdered paints according to claim 1, 11 and 12, characterized in that it modified acrylic as solid resins Polyester resins having a number average molecular weight of 500 to 20,000 and / or a content -k - _li of active hydrogen atoms from 3 χ 10 to .45 χ 10 MOl / g contain * 16 * Powdery paints according to claims i, 11, 12 and 15 characterized in that they are used as solid resins Acrylic modified polyester resins that have been prepared by polyester resins containing at least contain at least one active group in the molecule, and / one ethylenic unsaturated polymerizable compound and / or an acrylic resin of the additive polymerization *, condensation, Subjected to addition or chain transfer reaction will. '■ 17. Powdered paints according to claim 1, 11 and 12, characterized in that they are used as solid resins, epoxy resins, Affiino resins or polyether resins contain. L e r s e i t e