DE2528250B2 - THERMAL POWDER COATING COMPOUNDS - Google Patents

Description

characterized in that (A) is a graft copolymer

a) 10 to 40% by weight of a linear polyester with a numerical average molecular weight of 600 to 3000 and an ethylenically unsaturated double bond only at one end of the molecule,

b) 5 to 30% by weight of at least one glycidyl ester of the form!

5. Thermosetting powder coating composition according to claim 1 ois 4, characterized in that the graft copolymer contains the glycidyl ester in the range from 10 to 25% by weight

6. Thermosetting powder coating composition according to claim 1 to 5, characterized in that the graft copolymer furthermore at least one compound from the group of acrylonitrile, Methacrylonitrile and styrenes of the formula

\ -CH = CH,

wherein Re is a hydrogen atom or an alkyl radical with 1 to 4 carbon atoms means, in an amount up to 40 wt .-% contains

7. Thermosetting powder coating composition according to claim 6, characterized in that the Compound is contained in an amount of 5 to 30% by weight.

CH ₂ = C-COOCH ₂ -CH CH ₂

wherein Ri denotes a hydrogen atom or a methyl radical and
c) 10 to 85% by weight of at least one acrylic compound of the formula

CH ₂ = CCOOR ₃

wherein R _{2 is} a hydrogen atom or a methyl radical and R _{3 is} an alkyl radical having 1 to 14 carbon atoms, a cyclohexyl or hydroxyalkyl radical of the formula

-CH ₂ -CHOH

wherein R _{4 is} a hydrogen atom or an alkyl radical having 1 to 2 carbon atoms, the graft copolymer having a softening point of 70 to 110 ° C. and a number average molecular weight of 2,000 to 30,000

and that (B) is present in an amount of 0.6 to 1.2 mol in terms of carboxyl group per mole the glycidyl group contained in the graft copolymer.

2. Thermosetting powder coating composition according to claim 1, characterized in that the linear polyester has a numerical average molecular weight of 1,000 to 2,000.

3. Heat-curable powder coating composition according to claim 1 or 2, characterized in that that the graft copolymer has a number average molecular weight from 4000 to 20,000.

4. Thermosetting powder coating composition according to claim 1 to 3, characterized in that the graft copolymer has the linear polyester in the range of 15 to 30% by weight.

25 The invention relates to thermosetting powder coating compositions.
With the increasing severity of pollution of air, water and the like are

Powder coating compounds have been put into use with almost no pollution problems cause.

At present, epoxy resin or vinyl chloride resin is mainly used as a resin component of powder coating compositions However, powder coating compositions are used because of poor weather resistance of the epoxy resin type cannot be used outdoors, while those of the vinyl chloride resin type which are thermoplastic, have poor resistance to heat and solvents and therefore can only be used to a limited extent.

In order to overcome these problems, various powder coating compositions have recently been disclosed Acrylic type resins have been proposed which contain glycicyl groups as a functional group.

With such an acrylic resin type powder coating composition containing glycidyl functional groups, Efforts have been made to improve the thermal fluidity, crosslinking reaction rate and to sensibly maintain the softening point of the resin in equilibrium with each other, so that the mass shows good storability and gives smooth coatings, the high solvent resistance exhibit.

To establish this equilibrium, it is necessary to precisely determine the type of acrylate or methacrylate to be used, the amount thereof, the degree of polymerization and the amount of the monomer containing the functional group to be used. However, even with an optimal combination of these factors, the coating compound tends to block if it is applied or stored in an environment in which the outside temperature is likely to exceed ^{35 ° C.} The term "blocking" means the phenomenon in which particles of the coating composition cling to one another during storage. This disadvantage can be avoided if the bulk

ϊο is adapted to have an increased softening point at the expense of the smoothness of the coating to be produced therefrom, or by adding a cooling arrangement for the containers for storage and recovery of the coating material is provided. in the In the former case, the thermosetting acrylic resin type powder coating is no longer for decorative Surface finish coatings applicable for which the coating compositions are mainly used should, whereas the latter case entails higher equipment costs and operating costs and is unfavorable

Furthermore, powder coating compositions of the acrylic resin type require baking at high temperatures of at least 180 ⁰ C if a coating with superior mechanical properties, such as impact resistance, Erichsen test and flexural strength is desired, because low baking temperatures not only affect the mechanical properties of the coating, but also reduce their resistance to weathering, solvents and heat.

For use in decorative ceiling coatings, powder coating compounds should be used like conventional coating compounds solvent-type may be coatable to a small thickness of about 25 to 50 microns for economy, but conventional Acrylic resin type thermosetting powder coatings present difficulties in the Making thin coatings with them because they have high melt viscosity when used for Coating become coatable and exhibit poor flowability when heated to melt. Although such coating compositions can be adapted to form thin coatings by their Hardenability is reduced in order to make it more flowable in the molten state, this is not desirable, because the resulting coatings inferior in physical properties, solvent resistance etc are. On the other hand, the coating compound can be used to form thin coatings are made by lowering their softening point and thereby lowering their melt viscosity, however, the mass then has the disadvantage that the particles are connected during storage, what leads to decreased blocking resistance. Such a mass is therefore equally undesirable.

Accordingly, it is an object of the invention to provide an improved powder coating composition which is free from the above disadvantages of the known acrylic powder coating composition. Furthermore, the Mass be able to give coatings which have excellent mechanical strengths and has physical properties even when the masses are fired at low temperatures. In addition, the masses should be able to produce smooth, glossy coatings for decorative purposes to result in no undesired blocking, even if the mass is in a hot one Environment is applied or stored. The powder coating composition according to the invention should also be a have low melt viscosity and good flowability and thus be able to get smooth, shiny and yet easy to form thin coatings.

The invention relates to a thermosetting powder coating composition, consisting of:

A) a polymer with a glycidyl group,

B) at least one polycarboxylic acid or its anhydride and

C) usual additives,

characterized in that (A) is a graft copolymer is off

a) 10 to 40% by weight of a linear polyester having a numerical average molecular weight from 600 to 3000 and one ethylenically unsaturated double bond only at one end of the molecule,

b) 5 to 30% by weight of at least one glycidyl ester of the formula

R ₁ O

CH ₂ = C-COOCH ₂ -CH CH ₂

wherein Ri is a hydrogen atom or a Methyl radical means and

c) 10 to 85% by weight of at least one acrylic compound the formula

CH ₂ = CCOOR ₃

wherein R _{2 is} a hydrogen atom or a methyl radical and R3 is an alkyl radical having 1 to 14 carbon atoms, a cyclohexyl or hydroxyalkyl radical of the formula

-CH ₂ -CHOH

wherein R ₄ is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, mean, wherein the graft copolymers having a softening point of 70 to 110 ⁰ C and a numerical average molecular weight 2000-30000

and that (B) is present in an amount of 0.6 to 1.2 moles in terms of the carboxyl group per mole of the in that Graft copolymers containing glycidyl group.

The first advantage of the coating composition of the invention is that, when fired for 30 minutes at a temperature of 15O ⁰ C, so much lower than in the case of the conventional acrylic powder coating compositions give a coating, the mechanical properties such as impact resistance, Erichsen test and has flexural strength comparable to that resulting from epoxy resin powder coating compositions, which are the most excellent of the powder coating compositions currently available. In addition, the coatings produced from the present composition are in no way inferior to the usual powder coating compositions of the thermosetting acrylic resin type in terms of resistance to weathering, solvents and heat.

The second advantage of the coating composition of the invention is that that used herein Above mentioned graft copolymers of polyester and acrylic resin: the mass enables in the form of fine Particles to remain without blockage, so that they to

electrostatic coating or fluidized bed coating, even under severe operating conditions of 35 to 40 ^° C., such as when used in summer, can be applied, with the result that the composition can provide smooth and glossy surface coatings.

It is surprising that the above-mentioned graft copolymers of linear polyester and Acrylic polymer, although there are 10 to 40 Gev /.- o / o au / das Polymers containing grafted polyester, almost such ι ο raised softening point like ungrafted acrylic polymer and has a greatly reduced melt viscosity when heated

Due to the high softening point, the coating compound is less prone to it during storage or to block the coating process, so that the mass has high resistance to blocking and has good adaptability to the coating process

On the other hand, the low melt viscosity of the composition, when applied for coating, ensures good thermal flowability and provides a smooth top coat.

The third advantage of the coating composition of the invention is that the composition because of the low melt viscosity and good thermal flowability during the formation of the coating in is able to give smooth and glossy charges that are as thin as 25 to 50 microns have, while they have the desired hardenability and Maintain blocking resistance.

Thus, the various advantages of the invention are of using the listed graft copolymer Made of acrylic polymer and linear polyester.

According to the invention, the polyester constituting the above copolymer must be numerical Have an average molecular weight of 600 to 3000 and an ethylenically unsaturated one Only contain double bond at one end of the molecule. With a numerical average In molecular weight less than 600, the polyester has poor plasticizability and is ineffective in greatly reducing melt viscosity, thereby reducing smoothness and physical appearance Properties of the resulting coating are adversely affected. With a numerical average The molecular weight of more than 3000, the coating composition has a greatly reduced Softening point and poor blocking resistance. The preferred numerical average Molecular weight ranges from 1000 to 2000.

The process for producing the linear polyester having an ethylenically unsaturated double bond at one end of the molecule is in no way limiting to the invention, it merely has secondary importance. However, the polyester is most advantageously made by condensing a monohydroxy monocarboxylic acid or a mixture of the acid and monocarboxylic acid made to produce a linear To obtain polyester which has a free terminal carboxyl group and with Glycidylacrylai and / or glycidyl methacrylate reacts with the polyester. Usable monohydroxy monocarboxylic acids, which have a carboxyl group at the end of the molecule and a hydroxyl group in the molecule, are aliphatic monohydroxymonocarboxylic acids with 2 to 18 carbon atoms. Preferred examples are

12-hydroxystearic acid, ricinoleic acid, lactic acid etc., among which 12-hydroxystearic acid and ricinoleic acid are particularly preferred. The monohydroxy monocarboxylic acids can be used alone or in admixture with one another. Monocarboxylic acids can be used in Mixture with the monohydroxymonocarboxylic acid, if desired, can be used to increase the molecular weight of the resulting linear polyester. Usable monocarboxylic acids are aliphatic monocarboxylic acids with 1 to 18 carbon atoms and aromatic monocarboxylic acids of formula

COOH

where R ₅ denotes an alkyl radical having 1 to 4 carbon atoms and π 0 or an integer of 1 or 2. Preferred examples of the former are acetic acid, caproic acid, capyric acid, carpic acid, lauric acid, myristic acid, palmitic acid, stearic acid, etc. Preferred examples of the latter are benzoic acid. p-tert-butylbenzoic acid etc. Particularly preferred monocarboxylic acids are palmitic acid, stearic acid and p-tert-butylbenzoic acid. One or more of the monocarboxylic acids can be used. The hydroxymonocarboxylic acid alone or mixed with the monocarboxylic acid is subjected to the condensation reaction. If the monocarboxylic acid is used, its amount is up to 20 mol%, preferably 10 to 20 mol%, based on the hydroxymonocarboxylic acid.

The condensation reaction is carried out in the usual manner with or without a catalyst and with heating. Suitable catalysts are, for. B. sulfuric acid, dimethylsulfuric acid, methanesulfonic acid, etc. In general, the condensation temperature is about 130 to about 170 ^° C. The condensation reaction results in a linear polyester which has a carboxyl group at the end of the molecule

In order to introduce an ethylenically unsaturated double bond into the polyester at the end of the molecule, the polyester is then reacted with glycidyl acrylate and / or glycidyl methacrylate. An equivalent or an excess of glycidyl acrylate and / or methacrylate, based on the carboxyl group of the polyester, is used for this reaction. The excess glycidyl ester serves as the other monomer component A- (b) to finally obtain the desired graft copolymer. The reaction is advantageously carried out in the presence of catalysts such as trimethylamine, triethylamine, dimethylaminoethanol, dimethyl coconut amine or the like tertiary amine, or tetraethylammonium bromide, trimethylbenzylammonium chloride or the like quaternary ammonium salts. The reaction is usually carried out at a temperature of from 110 to 150 ^° C., preferably until the acid number of the product is reduced to a value of not more than 5.

Another component A- (b) of the graft copolymer is a glycidyl ester of the formula

R ₁ O

CH ₂ = C-COOCH ₂ -CH CH ₂

wherein Ri is a hydrogen atom or a methyl radical. Such esters are glycidyl acrylate and glycidyl methacrylate.

Another component A- (c) of the graft copolymer is an acrylic compound of the formula

CH ₂ = C-COOR ₃

wherein R _{2 is} a hydrogen atom or a methyl radical, R3 is an alkyl radical having 1 to 14 carbon atoms, a cyclohexyl radical or the grouping

R4
-CH ₂ -CHOH

mean, wherein R4 is a hydrogen atom or a Is an alkyl radical having 1 to 2 carbon atoms. Examples of such compounds are esters of acrylic acid and Methacrylic acid. These esters include

Methyl acrylate, ethyl acrylate, propyl acrylate,
n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate,
2-ethylhexyl acrylate, lauryl acrylate,
Methyl methacrylate, ethyl methacrylate,
Propyl methacrylate, n-butyl methacrylate,
Isobutyl methacrylate, tert-butyl methacrylate,
2-ethylhexyl methacrylate, lauryl methacrylate and the like alkyl esters; Cyclohexyl acrylate and
Cyclohexyl methacrylate and 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,
2- hydroxypropyl acrylate,
2-hydroxypropyl methacrylate and the like
Hydroxyalkyl esters.

Preferred acrylic compounds are

Methyl acrylate, ethyl acrylate, cyclohexyl acrylate
Methyl methacrylate, ethyl methacrylate,
n-butyl methacrylate, isobutyl methacrylate,
2-ethylhexyl methacrylate,
2-hydroxyethyl methacrylate and
Lauryl methacrylate.

These can be used alone or in admixture with one another.

The graft copolymer to be used in the invention is obtained by adding the above three components, namely linear polyester A- (a) having an ethylenically unsaturated double bond at the end of the molecule, glycidyl ester A- (b) and acrylic compounds A- (c) of Be subjected to graft copolymerization. The graft copolymers must have a softening point of up to 30000 7Ö to 110 ⁰ C and a numerical average molecular weight in 2000. When the softening point is below 70 ^° C., the blocking resistance of the resulting coating composition becomes poor. When the softening point is higher than 110 ^° C., the resulting coating has poor surface smoothness. If the graft table polymer has a numerical average molecular weight of less than 2000, the resulting coating has low mechanical strength and solvent resistance, while the coating composition has poor resistance to blocking coating, but increases the melt viscosity of the coating composition, making it impossible to obtain a smooth coating. Preferably the number average molecular weight of the graft copolymer is from 4,000 to 20,000.

The proportions of components A- (a), A- (b) and A- (c) which are to be copolymerized in the graft copolymer are critical and must be 10 to 40% by weight of linear polyester A- (a), 5 to 30% by weight of glycidyl ester A- (b) and 10 to 85% by weight of acrylic compound A- (c). When the amount of linear polyester is less than 10% by weight, it is impossible to fully obtain the effect intended by the invention.

More specific is like the one in the later example indicated mass No. 6 here before, a graft copolymer (GP-6), which is about. 5% by weight of the polyester contains, not particularly distinguishable from ungrafted copolymers, whereas those containing contain at least 10% by weight polyester, give an excellent effect.

This appears from the undermentioned Table 1, which shows the softening points and melting viscosities of the copolymers at 14O ⁰ C containing various amounts of polyester.

Table 1

Share of Enamel Softening Polyester im viscosity Point Mixed polymers (% By weight) (Poise) ( ⁰ C) 0 82 5 5300 87 10 1500 89 40 1300 82 50 1250 66

Comment:

The copolymers are prepared in the same way as the graft copolymers-4 given below, except that the amount of polyester-4 is varied

45 The table clearly shows that the use of 10 to 40% by weight of polyester for the graft copolymerization markedly reduces the melt viscosity without a marked reduction in the softening point. It can also be seen from the table that the use of more than 40% by weight polyester is not appreciably effective in reducing the melt viscosity while reducing the softening point

ss is noticeably lowered in order to reduce the blocking resistance of the coating compound (see compound No. 10 in the example given later). The proportion of polyester to be copolymerized is preferably about 15 to 30% by weight.

Less when the content of glycidyl ester of A- {b) 5 wt .-% ah is, there is insufficient cross-linking, unc it of the formed coating may be given a satisfactory solvent resistance and mechanical strength {see mass no. 13 in following Betspiel), whereas shares of flour than 30% by weight the course of the crosslinking reaction in excess during that forming the coating Operation enables, which leads to lower FBeBf!

709607/471

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ability during this work step and no longer makes the coating smooth (see Mass no. 14 in the following example). 10 to 25% by weight of glycidyl esters are preferably copolymerized.

The acrylic compound A- (c), another component of the graft copolymer and represented by formula

CH ₂ = C-COOR ₃

(where R2 and Rj are defined as above) should be in a Amount of at least 10% by weight can be used to ensure adhesion of the resulting coating the base (see dimensions no. 22 in the following example).

In addition to the above three ingredients, the graft copolymer useful in the invention further contains as copolymerizable monomer A- (d) up to 40% by weight of at least one of the compounds acrylonitrile, Methacrylonitrile and styrenes of form!

CH = CH ₂

wherein Rt is a hydrogen atom or an alkyliest having 1 to 4 carbon atoms. The styrenes of the above formula include styrene, vinyl toluene, etc. They are used alone or in admixture with one another.

When it contains the above monomer, the obtained dope shows better durability against blocking. The proportion of the additional monomer must be and is up to 40% by weight usually 5 to 30 weight percent. At a content of more than 40% by weight of the additional monomer the coating provides poor surface smoothness.

The graft copolymer is made by block polymerization, solution polymerization, suspension polymerization, Emulsion polymerization, etc., with solution polymerization being the most preferred

In the solution polymerization, various organic solvents are usable, such as aliphatic hydrocarbons, aromatic hydrocarbons, etc. Solution polymerization can be carried out in the presence of polymerization initiators. Examples of this are organic Peroxides, such as benzoyl peroxide, lauroyl peroxide, tert-butyl hydroperoxide, tert-butyl peroxyoctate, Isobutanoyl peroxide etc. and azo compounds such as for example azobisisobutyronitrile azobisisovaleronitrile etc The solution polymerization reaction is usually carried out at reflux temperature

The powder coating composition of the invention contains the above-described graft copolymer and at least one polycarboxylic acid or its anhydride Usable polycarboxylic acids are aliphatic, alicyclic and aromatic polycarboxylic acids, which as Curing agents for acrylic resins that contain a glycidyl functional group are known to be more specific Examples of polycarboxylic acids are aliphatic polycarboxylic acids such as adipic acid, Azelaic acid, sebacic acid, dodecanedicarboxylic acid, fu-

marsic acid, maleic acid, succinic acid, tricarballylic acid, etc .; alicyclic polycarboxylic acids such as Tetrahydrophthalic acid, hexahydrophthalic acid, etc. and aromatic polycarboxylic acids such as Phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, Pyromellitic acid, etc. The anhydrides of such polycarboxylic acids are equally useful. The polycarboxylic acids and their anhydrides are used alone or at least two of them are in Mixture usable.

To produce the powder coating composition according to the invention, at least one of the above is used Polycarboxylic acids and their anhydrides in an amount of 0.6 to 1.2 mol in terms of carboxyl group per Mole of glycidyl group contained in the graft copolymer is used. Lead smaller amounts insufficient curing and therefore lower mechanical strength and solvent resistance the resulting coating (see dimensions

No. 19 in the example below), while excess amounts result in reduced surface smoothness and poor physical properties of the coating (see Compound No. 20 in the example).
The powder coating composition of the invention contains

also organic and inorganic pigments, flow agents, curing catalysts, antistatic agents, etc. which are generally used for coating compositions. Can be used as curing catalysts are z. B. tert-amines, quaternary ammonium salt,

organic tin compounds such as triphenyl tin chloride and dibutyl tin laurate and titanium compounds such as tetraisopropyl titanate

The powder coating can be carried out by any conventional method, z. B. by mixing the ingredients in the molten state or by formulating the ingredients hi a solution and then removing the solvent.

To illustrate the invention, the following examples for the production of linear polyester (A) -a, Graft copolymers (A) and coating compositions indicated.

40 Manufacture of polyester

1. Polyester-1 (PE-I)

A 3000 g amount of 12-hydroxystearic acid, 150 g

Of toluene and 5 g of methanesulfonic acid, which serves as a catalyst are introduced into a vessel equipped with a thermometer, a water trap and a stirrer 5-1 reaction vessel, and the mixture is subjected to dehydration condensation at 150 ⁰ C 4Stan-

subjected to the production of a polyester in the form of a viscous liquid, which is an acid anzafol of 32 and has a molecular weight of about 1750 The polyester is referred to below as "Polyester-1 '" or "PE-1'"

A 1000 g portion of the polyester J ', 140 g glycidyl methacrylate, 0.5 g of hydroquinone and 1000 g of toluene are poured into a with a counter-magneto, a Place a 5-1 reaction vessel equipped with a thermometer and a stirrer, and the mixture is

at 130 ° C under reflux for 10 hours to obtain a Polyester (similar to »Polyester-1« or »PE -! * referred to) implemented, which has an acid number of 0.2 peat has a molecular weight of about 1890

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2. Polyester-2 (PE-2)

Exactly the same procedure as in the case of the polyester! ' is obeyed, except that the Dehydration condensation is carried out for 1.5 hours to obtain a polyester (hereinafter referred to as »Polyester ^ '« or »PE-2'«) in the form of a viscous liquid with an acid number of 56 and a molecular weight of about 1000.

The polyester 2 'and those in the following Table II listed compound in the specified amount are processed in the same manner as in the case of the Polyester-1 to obtain a polyester (hereinafter referred to as "Polyester-2" or "PE-2"), the properties given in the same table having.

4. Polyester-4 (PE-4)

5. Polyester-5 (PE-5)

which has an acid number of 80 and a molecular weight of 700.

The polyester 5 'and those in the following Table II listed compound in the specified amount are produced in the same manner as in the case of polyester-1 to obtain a polyester (hereinafter referred to as "Polyester-5" or "PE-5") implemented which has the properties listed in the same table.

3.Polyester-3 (PE-3)

Exactly the same procedure as in the case of polyester Γ is followed except that the dehydration condensation is carried out for 10 hours a polyester (hereinafter referred to as "polyester-3 '" or "PE-3'") in the form of a viscous liquid which has an acid number of 20 and a molecular weight of about 2,800.

The polyester 3 'and the compound listed in the following Table II in the specified amount are processed in the same manner as in the case of polyester-1 to obtain a polyester (hereinafter referred to as »Polyester-3« or »PE-3 called), which has the properties specified in the same table having.

6. Polyester-6 (PE-6)

Exactly the same procedure as in the case of polyester Γ is followed except that the dehydration condensation is 3.5 hours using of 2500 g of 12-hydroxystearic acid and 400 g of coconut oil fatty acid is designed to produce a polyester (hereinafter referred to as "Polyester-6 '" or "PE-6'") in the form of a viscous liquid that has an acid number of 35 and a molecular weight of about 1600 has.

The polyester 6 'and those in the following Table II listed compound in the specified amount are produced in the same manner as in the case of polyester-1 to obtain a polyester (hereinafter referred to as "Polyester-6" or "PE-6") implemented which has the properties given in the same table.

Exactly the same procedure as in the case of polyester Γ is followed except that the Dehydration condensation for 3 hours using 2800 g of ricinoleic acid and 200 g of tert-butylbenzoic acid instead of 3000 g of 12-hydroxystearic acid, a polyester (hereinafter referred to as "Polyester-4 '" or "PE-4'") in the form of a viscous liquid that has an acid number of 37.4 and a molecular weight of about 1,500.

The polyester 4 'and those listed in Table II below listed compound in the specified amount are processed in the same manner as in the case of the Polyester-1 to obtain a polyester (hereinafter referred to as "Polyester-4" or "PE-4") implemented which has the properties listed in the same table

7. Polyester-7 (PE-7)

Exactly the same procedure as in the case of polyester Γ is followed except that the dehydration condensation is 1.5 hours using from 1500 g of L? -hydroxystearic acid and 1500 g of lactic acid is carried out to produce a polyester (hereinafter referred to as "Polyester-7 '" or "PE-7'") in the form of a viscous liquid that has a Has an acid number of 150 and a molecular weight of about 375.

The polyester 7 'and the compounds listed in the following Table II, in each case in the listed Amount are reacted in the same manner as in the case of polyester-1 to form a polyester (hereinafter referred to as "Polyester-7" or "PE-7"), the one specified in the same table Has properties.

60

Exactly the same procedure as in the case of polyester Γ is followed except that the Dehydration condensation for 2 hours using 2500 g of 12-hydroxystearin saturation and 500 g Lactic acid is carried out to produce a polyester (hereinafter referred to as "Polyester-5 '" or "PE-5'")

8. Polyester-8 (PE-8)

Exactly the same procedure as in the case of polyester-1 'is followed except that the dehydration condensation is carried out for 5 hours a polyester (hereinafter referred to as "Polyester-8 '" odei »PE-8 '«) in the form of a viscous liquid to obtain which has an acid number of 15 and a molecular weight of about 3740

The polyester-8 'and the compound listed in the following table I in the specified amount are converted in the same way as fan Fai of the polyester-J to a polyester (hereinafter referred to as "polyester-8" or "PE-8") ) which has the property given in the same table

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Table Il

Received GMA GA Ver solvent catalyst Polymerization Reak acid Molecular polyester turned inhibitor ions number weight polyester Time (G) (G) (G) (G) (G) (G) (Hours)

PE-2 200 70 PE-2 '
1000 toluene
1000 Dimethyl
coconut amine
1.0 Hydroquinone
monoäthvläther
0.5 6.5 0.5 1140 PE-3 " - PE-3 '
1000 Ethyl acetate
1000 Tetraethyl
ammonium-
bromide 1.0 Hydroquinone
0.5 12th 0.2 2930 PE-4 110 - PE-4 '
1000 toluene
1000 the same the same 5 0.2 1640 PE-5 280 110 PE-5 '
1000 Butyl acetate
1000 - the same 7th 0.3 840 PE-6 - - PE-6 '
1000 toluene
1000 Triethylamine
1.0 the same 5 0.2 1730 PE-7 450 - PE-7 '
1000 toluene
1000 the same the same 7th 0.5 515 PE-8 56 PE-8 '
1000 toluene
1000 the same the same 6th 0.3 3880

Remarks:

»GMA« = glycidyl methacrylate,

"GA" = glycidyl acrylate.

Production of graft copolymers
1. Graft Copolymer-1

A 1000 g amount of toluene is placed in a 5-1 four-necked flask equipped with a reflux condenser, stirrer and dropping funnel and is heated to reflux temperature in a nitrogen atmosphere. A mixture of 700 g of polyester-1, 150 g of methyl methacrylate, 150 g of n-butyl methacrylate, 200 g of styrene, 150 g of glycidyl methacrylate and 30 g of azobisisobutyronitrile, placed in a dropping funnel, is added dropwise to the toluene kept at the same temperature over a period of 3 hours added. Further, at the same temperature, a mixture of 3 g of azobisisobutyronitrile and 30 g of ethyl acetate is added dropwise to the resulting solution three times with an interval of 1 hour. (The catalyst thus added is hereinafter referred to as an "additional catalyst") After the mixture has been refluxed for 2 hours, the condenser is replaced by a cocurrent condenser, and there; Mixture is slowly heated to 15O ⁰ C, while as: can proceed solvent and the unreacted monomers from the flask. After about 60 ° / c of the introduced solvent has been withdrawn, the inside of the flask is kept at 170 ° C. under a reduced pressure of 30 mmHg for 20 minutes, and then the contents are placed in a stainless steel container and solidified by a cooler to produce a graft copolymer-1 (PE-I).

2.-19. Graft copolymers-1 to-19

In exactly the same manner as above, graft copolymers -2 to -19 (GP-2 to GP-19) are divided Using the specified amounts of the materials listed in Table III. Table IV there the masses and properties of the graft copolymers obtained.

Table III

Received Solution polyester component Away) component A- (C) component Poly Additional Graft middle A-Cd) merization licher mixed poly initiator catalyst meres <g) te) (G) (G) fe) Cg)

GP-2 Totaol PE-2

100Θ 250

Glycidyl methacrylate 50

2-hydroxyethyl methacrylate 50

2-ethylhexyl acrylate 150

Cyclohexyl methacrylate 400

Styrene 150

Vinyl tolaol
150

Beazoy ^ eroxide 20

Benzoyl peroxad 3

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q ¹ GP-12 GP-15 1 G 15th _x 25 28 250 component 16 80 tert-butyl Additional To continue Solution ? alyester A- (d) Poly peroxyoctate licher Received j middle Component A- (b) Component A- (c) merization 30th catalyst P drop i GP-13 initiator tert-butyl mixed poly GP-16 'GP-17 (G) peroxyoctate (G) meres j j (G) (G) 70 ⁱ GP-14 j (G) (G) i Lauryl meth- Styrene 200 acrylate 150 tert-butyl Benzoyl ethyl PE-3 Benzoyl peroxyoctate peroxide 3 GP-3 acetate 1000 500 Glycidyl meth- Methylmeth- Acrylonitrile peroxide 8 25th acrylate 170 acrylate 150 the same n-butyl acrylate Styrene 290 tert-butyl toluene PE-4 150 the same peroxy GP-4 1000 400 Glycidyl acrylate 2-ethylhexyl- octate 3 250 acrylate 150 Styrene 500 the same tert-butyl Butyl PE-5 peroxy GP-5 acetate 600 Glycidyl meth- n-butyl acrylate octate 6 1000 acrylate 250 175 the same Ethyl meth - the same tert.-ButyJ- toluene PE-6 acrylate 600 peroxy GP-6 1000 100 Glycidyl meth- the same octate 3 acrylate 230 n-butyl meth- - tert-butyl the same toluene PE-6 acrylate 140 peroxyoctate I GP-7 1000 400 Glycidyl meth- Ethyl methacrylate - 25th the same toluene PE-6 acrylate 200 600 j GP-8 1000 600 Glycidyl meth- Ethyl methacrylate - the same the same toluene PE-6 acrylate 200 500 j GP-9 1000 770 Glycidyl meth- Ethyl methacrylate tert-butyl acrylate 200 410 - peroxyoctate the same toluene
1000 PE-6
1000 Ethyl methacrylate 100 j GP-IO Glycidyl meth-
acrylate 200 200
Methylmeth- - the same toluene PE-7 acrylate 100 GP-Il 1000 400 Glycidyl meth- Ethyl methacrylate - the same toluene PE-8 acrylate 200 600 tert-butyl 1000 400 Glycidyl meth- Ethyl methacrylate peroxyoctate tert-butyl acrylate 200 600 4th peroxy toluene PE-6 Ethyl methacrylate octate 3 1000 400 Glycidyl meth- bOO teri.-butyl- acrylate 20 2-hydroxyethyl - peroxyoctate the same toluene PE-6 methacrylate 150 25th 1000 400 Glycidyl meth- Ethyl methacrylate tert-butyl acrylate 400 400 peroxy toluene PE-6 Ethyl methacrylate octate 10 1000 400 Glycidyl meth- 400 acrylate 200 Methylmeth- acrylate 200 ethyl PE-6 Ethyl methacrylate - tert-butyl acetate 400 Glycidyl 400 peroxy 1000 methacrylate 200 n-butyl octate 3 methacrylate 200 - tert-butyl toluene PE-6 Ethyl methacrylate peroxy 1000 400 Glycidyl 300 ' octate 3 methacrylate 200 n-butyl meth- acrylate 300

continuation

Solvent-graft agent obtained
mixed polymer

Polyester component A- (b) component A- (c)

(G)

(G)

(G)

component Poly- Additional A- (d) merisaüons- licher initiator catalyst (ε) (E) (S) tert-butyl tert-butyl peroxyoctate peroxy 25th octate 3 f tert-ButyJ- I styrene 200 tert-butyl tert-butyl ] Vinyl toluene peroxyoctate peroxy 1160 25th octate 3

GP-18 toluene PE-6 glycidyl methyl meth-

1000 400 methacrylate 200 acrylate

GP-19 toluene PE-6 glycidyl n-butyl acrylate

1000 770 methacrylate 200

Table IV

Graft copolymer

Polyester component A- (a)

Component Mb)

Component A- (C) component
A- (d)

(% By weight) (% by weight) (% by weight) (% by weight)

Molecular weight softening point

GP-I 32.8 17.0 30.1 20.1 5,500 87 GP-2 ii, 9 5.3 55.2 27.6 8,300 89 GP-3 2i, a 15.1 38.9 24.2 25,000 105 GP-4 23.0 28.1 16.7 32.2 5,200 81 GP-5 25.1 21.4 13.9 39.6 2,600 72 GP-6 5.0 22.6 72.4 - 6,300 87 GP-7 20.3 20.3 59.4 - 6 600 87 GP-8 30.2 20.5 49.3 _ 6 700 83 GP-9 38.9 20.7 40.4 6,800 82 GPlO 49.9 20.9 29.2 6 950 66 GP-Il 21.6 20.5 57.9 6,300 84 GP-12 20.1 20.3 59.6 6 700 65 GP-13 20.9 2.6 76.5 - 6 650 92 GP-14 20.3 40.1 39.6 _ 6 700 83 GP-15 20.3 20.3 69.7 1600 73 GP-16 20.3 20.3 69.7 35,000 101 GP-17 20.3 20.3 69.7 - 6 650 63 GP-18 20.3 20.3 69.7 - 6 750 124 GP-19 38.9 20.7 5.2 35.2 7 200 75

Production of powder coating compounds

Powder coating wipes are made using the methods listed in Table V below Quantities of the specified ingredients.

The masses No. 1 to 7, 7 to 9 and 21 are compositions according to the invention. The other compositions are made for comparison.

The constituents are kneaded with hot rollers at HO ⁰ C for 20 minutes, and the mixture is solidified by cooling, coarsely comminuted, then

Table V

pulverized and sieved to obtain fine particles that pass through a sieve with sieve openings of 104 μm. The fine powder is then applied electrostatically to a 0.8 mm thick mild steel sheet which has been treated with zinc phosphate, and the coated sheet is ^{heated at 150 °} C. for 30 minutes to produce a test panel. The coating was 40 ± 5 microns thick.

Graft copolymer

(G)

Dicarboxylic acid (g)

Carboxyl / gly catalyst

cidyl

(Molar ratio) (g) additive
(G)

pigment
(G)

1 GP-I 1000 Adipic acid 68 0.78 Triphenyl tin j benzoin 3.0 5 Polylauryl acrylate 10 rutile-like chloride 5 \ Superplasticizer * ') 5.0 Titanium dioxide 300 2 GP-2 1000 Adipic acid 30 1.10 the same - the same 3 GP-3 1000 Sebacic acid 91 0.90 the same - the same 4th GP-4 1000 Sebacic acid 129 0.65 - _ the same 5 GP-5 1000 Sebacic acid 136 0.90 Trimethylbenzyl Polylauryl acrylate 10 the same ammonium chloride 6th GP-6 Dodecanoic acid
181 0.90 the same the same

/in

19th

Mass graft mix
No polymeres (G) Dicarboxylic acid Carboxyl / gly-
cidyl catalyst additive pigment GP-7 1000 (ε) (Molar ratio) (G) (S) (G) 7th Dodecandioin 0.75 Trimethylbenzyl epoxy resin * ² ) 20 rutile-like acid 135 ammonium chloride 5 Ilieminel 5 Titanium dioxide GP-8 1000 300 8th Dodecandioin 0.90 desgL Superplasticizer 10 Phthalo acid 164 cyanine blue GF-9 1000 300 9 Azelaic acid 136 0.90 Dibutyl tin the same desgL GP-IO 1000 laurylate 7 10 Adipic acid 106 0.90 the same the same rutile-like
^J l'itQnrlitftYtH GP-Il 1000 I llallUlvJAlU
300 11th GP-12 1000 Sebacic acid 130 0.90 the same the same the same 12th GP-13 1000 Sebacic acid 129 0.90 the same the same the same 13th GP-14 1000 Sebacic acid 22 1.0 the same the same the same 14th GP-15 1000 Sebacic acid 251 0.8 the same the same the same 15th GP-16 1000 Sebacic acid 143 0.9 the same the same the same 16 GP-17 1000 the same 0.9 the same the same the same 17th GP-18 1000 the same 0.9 the same the same the same 18th GP-I 1000 the same 0.9 the same the same the same 19th GP-I 1000 Sebacic acid 54 0.45 the same the same the same 20th GP-7 1000 Sebacic acid 159 1.32 the same the same the same 21 Dodecandioin 0.75 the same the same the same GP-19 1000 acid 135 22nd Comment:
ι) polyacrylate. Azelaic acid 136 0.90 the same the same the same Condensation polymer made from epichlorohydride ι and bisphenol A.

The coating compositions are examined with the results given in Tables VI and VII.

Table Vl

Mass Blocking Resistance No.

30 ° C 40 ° C

resistance
against gasoline

5 10

12th

15th
17th

Well

partially

blocked

partially

blocked

blocked

blocked

Well
blocked

blocked

blocked
blocked

2H-HB
HB

H-2B

H-2B
HB-6B

The results show that while the composition of the invention (composition No. 5) has good blocking resistance

d 17 h idi

Molecular weight of the graft copolymer (No. 15) and the exceptionally low softening point Di l i M id

exercises, the masses No. 10, 12, 15 and 17 have very low 55 tes (No. 17). The latter four are masses

··· 'of resistance to gasoline

Blocking resistance due to the excess polyester content (No. 10), the high molecular weight the polyester (No. 12), the extremely small

Table VU

also with regard to
inferior.

Dimensions
No.

resistance
against gasoline

60 °

Mirrors-

gianz

Impact resistance

(! SOO g χ 13 mm 0)

Erichsen test flexural strength

(mm)

Surface smoothness, blocking resistance

(40 ° C, 7 days)

H-HB
H-HB

> 50 50

> 7

Well
Well

Well
Well

good Good

continuation resistance 60 ° Blow Erichsen test Flexural strength Surface smoothness Blocking Dimensions against gasoline Mirrors-
pi a Π7 strength resistance No, (500gx (mm) (40 ⁰ C, 7 days) 13mm0) 2H-H 50 7th Well Well Well 3 2H-H - 50 7th Well Well Well 4th 2H-HB - 50 7th Well Well Well 5 2H-H - 10 1.5 bad pretty good Well 6th 2H-H - 50 7th Well Well Well 7th 2H-H - 50 7th Well Well Well 8th H-HB - > 50 7th Well Well Well 9 2H-H - 15th 2.5 bad bad Well 11th HB- <6B 10 1.0 bad Well Well 13th 3H-H - 35 3.5 bad bad Well 14th H-2B - 20th 2.0 bad Well bad 15th 3H-H - 50 7th Well bad Well 16 3H-H - 20th 2.5 bad bad Well 18th H- <6B - 15th 1.0 bad Well Well 19th 2H-H - 20th 1.5 bad bad Well 20th 2H-H 98 50 7th Well Well Well . 21 The coatings
P _ ι _ ... ι τ · ".1 Ii mti are examined with the in the 6. Adhesion

Table VIII Flexural strength adhesion Mass no. Well
bad
Experimental procedure Well
bad 9
22nd

1. Blocking resistance

The mass is kept at 40 ± 0.5 ° C. or 30 ± 0.5 ° C. for 7 days while it is subjected to a load of 30 g / cm ² and then viewed. If the sample proves to be unchanged and free from blockage, it is rated as "good".

2. Resistance to gasoline

The test plate is immersed in gasoline at 20 ° C for 24 hours and the immersed part becomes then examined for pencil hardness according to JIS method K 5400,6,14. The result is expressed as a change in hardness before immersion to hardness after immersion, e.g. B. as »2H— HB«, specified. The smaller the change, the better the resistance to gasoline.

3. Mirror finish

Determined in accordance with JIS K 5400,6,7.
4. Flexural strength

The test plate is placed with the coated surface facing upwards over a round rod of 10 mm Diameter bent over an angle of 90 ° in one second, and the coating is checked for cracks examined. If the coating cracks, the sample is rated "poor". The investigation is at 20 ° C.

The test plate is immersed in boiling water for 2 hours, then stand in air at 20 ° C. for 1 hour left, and the coating becomes the surface of the

Base cut crosswise. A cellophane tape is on glued the cross-cut part and then quickly peeled it off. When the coating is peeled off, the mass is rated as "bad".

7. Softening point

Determined by the ring and ball method (JIS K 2513).

8. Impact resistance

After a coated plate was left to stand in a constant temperature and constant humidity chamber at a temperature of 20 ± 1 ° C and a humidity of 75% for 1 hour, the following test is carried out in the same chamber. A carrier and a center of percussion of prescribed sizes (13 mm diameter) are fitted to a Du Pont impact examination apparatus, and the plate is pushed in between, ^wobe: the coated surface of the panel is turned upward. The prescribed weight (500 g) is dropped on the center of the blow from the prescribed height, and the plate is taken out, and after standing in the room for 1 hour, the damage to the surface is observed. The greatest height (cm) that does not cause damage to the coating is determined.

9. Erichsen test

The coated plate is kept in a constant temperature and humidity chamber for 1 hour 20 ° C and a humidity of 75%. The plate is then placed on an Erichsen examination device brought with the coating applied on the outside. A punch that has a radius of 10 mm is a predetermined distance in contact with the rear surface of the plate

23 24

to determine the most uniform possible speed of (mm) of the punch stroke, the none

about 0.1 mm / sec. pushed outwards. Which causes changes on the coating, ejected part of the plate is unarmed with

Keep an eye out for cracks or peeling immediately after the ^ia surface finish

Pushing out examined to the maximum distance 5 Determined with the naked eye.

803 «·

Claims (1)

Patent claims: L Thermosetting powder coating compound, consisting of: S A) a polymer with a glycidyl group, B) at least one polycarboxylic acid or its anhydride and C) usual additives,