CN1425048A - Carboxyl-functional polyester epoxy resin powder coatings based on 1,3-propanediol - Google Patents

Abstract

A polyester powder coating composition formed by reacting: a) a polyester resin formed by reacting one or more aliphatic glycols and one or more polycarboxylic acids and/or anhydrides, wherein the aliphatic glycol is comprised of 5 to 90% 1,3-propanediol on a molar basis, in the presence of an esterification catalyst and then endcapping the polyester with an endcapping agent to ensure that the polyester has carboxyl chain ends; and b) an epoxy resin crosslinking agent.

Description

Based on 1, the carboxyl-functional polyester epoxy resin powder coatings of ammediol

Invention field

The present invention relates to the polyester powder coating of cross linking of epoxy resin.More particularly, the present invention relates to 1, and ammediol (1,3-PDO) make in carboxyl-functional polyester-epoxy coating polyester modification commonly used improve snappiness and shock-resistance significantly, other key property is very wide by 1, and is constant in the 3-PDO concentration range.In addition, described 1, the melt viscosity of the polyester of 3-PDO modification is lower than the polyester for preparing with 100% neopentyl glycol.

Background of invention

The exploitation of powder coating in recent years increases day by day.Powder coating does not discharge hazardous solvent in coating process, can under the situation of no waste almost, be coated with in very effective mode, thereby friendly and economical especially to environment.The available powder coating can obtain with curable epoxy powder coating.Commercially available many epoxy powder coatings comprise the solid polyester polyvalent alcohol with epoxy resin cure at present.

The polymkeric substance that is used to produce powder coating roughly is divided into thermosetting or thermoplastic.Thermosetting coating generally than thermoplastic compounds deutero-coating toughness better, more anti-solvent and washing composition, better with the bonding of metal matrix and softening when being subjected to high temperature.But being solidificated in of thermosetting coating obtains also can throw into question in good slickness and flexible coating are arranged except that above-mentioned ideal performance.

Thermosetting powder coating(s) can be divided into epoxy, epoxy-polyester, polyester-polyurethane, TGIC polyester and acrylic acid or the like.Epoxy-polyester coating has than better tint retention of epoxide powder coating and UV patience.This type of coating is widely used for housed device such as refrigerator, freezing plant, washing machine, stove and other galley equipment, art metal furniture, construction industry top ceiling, Shower cabinet, auto parts, farm equipment, reaches machinery, engineering and electronic component.

By thermosetting coating compositions deutero-coating good shock strength, hardness, snappiness and anti-solvent and chemical moral character should be arranged.For example, be used for being coated with will be with various angles the curved or folding metal sheet powder paint compositions that forms the used steel plate of goods (circle) that is used to produce various home appliances and automobile good snappiness is arranged is necessary.

Based on carboxy(l)polyester such as neopentyl glycol base carboxy(l)polyester and trimeric cyanamide-, benzoguanamine-and the powder coating system of urea-aldehyde cross-linking agent be used for coatings industry.Referring to for example those described in the US-A-5 739204.EP-A-0008344 discloses a kind of similar system, mentions and uses 1,3-PDO.

Neopentyl glycol itself or its mixture usually and terephthalic acid and m-phthalic acid one be used from the preparation polyester powder coating, use a small amount of TriMethylolPropane(TMP) branching alternatively.Typically make in this type of powder coating used polyester modification when improving snappiness, shock-resistance and toughness, then sacrifice other performance very important described coating.Other possible properties-correcting agent comprises hexanodioic acid, 1,4-butyleneglycol and 2-methyl isophthalic acid, ammediol.

As if in the polyester epoxy resin powder coatings composition of carboxyl-functional, mix 1 without any the reference suggestion in the prior art, ammediol is to improve shock-resistance and snappiness under the situation of not losing other key property, and described 1, the polyester melt viscosity of 3-PDO modification is lower than the polyester for preparing with 100% neopentyl glycol.

Summary of the invention

Based on above-mentioned situation, the present invention includes a kind of polyester powder coating composition, form by following substance reaction:

A) one or more aliphatic diol and one or more polycarboxylic acid and/or acid anhydride react in the presence of esterifying catalyst then and make the vibrin of described polyester end-blocking to guarantee that described polyester has the carboxyl chain end to form with end-capping reagent, wherein said aliphatic diol comprises 5 to 90% (moles) 1, ammediol; With

B) epoxy resin cross-linking agent.

Now prove: by with 1, ammediol partly replaces described neopentyl glycol, described formula table reveals the shock-resistance and the snappiness of improvement, and other key property is very wide by 1, constant substantially in the ammediol concentration range, and described 1, the polyester of 3-PDO modification has than the lower melt viscosity of polyester with the preparation of 100% neopentyl glycol.

According to the present invention, a kind of polyester powder coating composition also is provided, form by following substance reaction:

A) wherein 1, ammediol accounts for the neopentyl glycol and 1 of 5 to 90% (moles), and terephthalic acid and the mixture of m-phthalic acid of the ratio of the mixture of ammediol and terephthalic acid wherein and m-phthalic acid in 90/10 to 50/50 scope reacts in the presence of dibutyl tin oxide and add the vibrin that trimellitic acid 1,2-anhydride forms described polyester end-blocking then; With

B) epoxy resin cross-linking agent, it be with bisphenol-a reaction and weight/epoxy be 450 to 900 2, the diglycidyl ether of two (4-hydroxyphenyl) propane of 2-.

The present invention also provides any coated product with powder paint compositions preparation of the present invention.

The accompanying drawing summary

Pass through case description the present invention below in conjunction with accompanying drawing, wherein:

Fig. 1 illustrates the second-order transition temperature of various prescriptions;

Fig. 2 illustrates differential scanning calorimetry (DSC) curve of carboxyl polyester resin;

Fig. 3 illustrates differential scanning calorimetry (DSC) curve of polyester/epoxy hybrid powder coatings; With

Fig. 4 illustrates the gloss of transparent and colored polyester/epoxide powder coating.

Detailed Description Of The Invention

Found with 5 to 90% among the present invention, preferred 10 to 50% (moles) 1, ammediol (1,3-PDO) the replacement preferred neopentyl glycol of described aliphatic diol (NPG) can improve resistance to impact and the pliability of the polyester powder coating of cross linking of epoxy resin significantly, and other performance is basic identical with the contrast coating with 100%NPG; And described 1, the polyester of 3-PDO modification has than the lower melt viscosity of polyester with the preparation of 100% neopentyl glycol. The performance of polyester of the carboxy blocking of examination be before carboxyl equivalent, acid number, the grinding color, glass transition temperature (Tg), processability, storage stability, just/reverse side impact, powder flowbility, powdered reaction, hardness, viscosity, the two frictions of MEK, chemical resistance and stain resistance.

The polyester of preferred carboxy blocking is characterised in that: acid number is 30 to 120mg KOH/g, preferred 40 to 110mg KOH/g, and Tg is greater than 40 ℃. Described acid number=56 100/ equivalents (56 100 is weight mg of every mole of KOH). Low or the acid number of equivalent is high to cause crosslink density and fragility high, causes crosslink density low and equivalent height or acid number are low, thereby poor performance such as anti-MEK and solvent resistance are low etc. Described Tg scope is that good storage stability is required.

The initiation material of polyester of the present invention is that aliphatic diol comprises 1,3-PDO, aromatic polycarboxylic acid or acid anhydride, esterification catalyst and optional branching agent. Being used for the coating material solidified initiation material of the present invention is described polyester, one or more epoxy resin, crosslinking catalyst and optional conditioner, auxiliary agent and the additive that comprises 1,3-PDO.

Applicable aliphatic diol has 62 to 500 number-average molecular weight, optionally comprises ether, ester group and/or carbonate group. Applicable aliphatic diol includes but not limited to ethylene glycol, 1,2-propane diols, 2-methyl isophthalic acid, ammediol, 1,3-and BDO, 1,6-hexylene glycol, diethylene glycol (DEG), DPG, neopentyl glycol, and the mixture of these glycol. Other applicable glycol comprises that triethylene glycol, tetraethylene glycol, tripropylene glycol, four propane diols, hydroxyl value are the mixture of about PCDL of 56 to 168, dimerization fatty alcohol and these glycol. Described reactive hydroxyl component (carboxyl, acid amides) can be simple monomeric unit or oligomeric unit or low-molecular-weight polymeric unit. Preferred glycol is aliphatic diol such as 1,3-BDO or BDO; Ethylene glycol and propane diols; And neopentyl glycol. Neopentyl glycol is most preferred, uses neopentyl glycol among the embodiment of this paper. As hereinafter described, a small amount of ternary or higher alcohol are also applicable.

Applicable acid comprises saturated, unsaturated, aliphatic or aromatic polycarboxylic acid and/or acid anhydride such as phthalic acid, M-phthalic acid, terephthalic acid (TPA), decanedioic acid, maleic acid, fumaric acid, butanedioic acid, adipic acid, azelaic acid, malonic acid, dodecanedioic acid, trimellitic acid, PMA and similar polybasic carboxylic acid or its mixture. Preferred polybasic carboxylic acid and/or acid anhydride are M-phthalic acid, terephthalic acid (TPA) and the trimellitic acids that is used alone or as a mixture among the present invention. Preferably use the described acid that in this reactions steps, forms. Most preferably mol ratio is 90/10 to 50/50 terephthalic acid (TPA) and the mixture of M-phthalic acid.

Branching agent also can use, for example a small amount of triol or higher alcohol. Applicable branching agent includes but not limited to trimethylolethane, trimethylolpropane or pentaerythrite. Trimethylolpropane preferably.

The polyester of carboxyl-functional of the present invention can pass through two step synthesis. This is an esterification. The first step makes the reaction under the temperature in 150 to 250 ℃, preferred 170 to 230 ℃ of scopes of binary acid such as terephthalic acid (TPA) (TPA), M-phthalic acid (IPA), polyalcohol such as NPG and PDO glycol and optional branching agent such as trimethylolpropane form hydroxy-end capped prepolymer.

Second step makes described hydroxy-end capped formation acid polyester with carboxylic acid or its acid anhydride. The consumption of end-capping reagent depends on the hydroxyl value of described polyester. General all the chain end end-blockings required stoichiometric 80 to 100% that make described polyester that add. Spendable end-capping reagent generally is the acid or anhydride that comprises a plurality of carboxylic acid groups, i.e. per molecule two or more carboxyl. Applicable acid comprises saturated, unsaturated, aliphatic or aromatic dicarboxylic acid such as phthalic acid, M-phthalic acid, terephthalic acid (TPA), decanedioic acid, maleic acid, fumaric acid, butanedioic acid, adipic acid, azelaic acid, malonic acid, dodecanedioic acid, trimellitic acid, PMA or its mixture. Terephthalic acid (TPA) is preferred, it is most preferred that M-phthalic acid. These sour acid anhydrides (if any) also can be used as end-capping reagent and are preferred, comprise the acid anhydride of above-mentioned acid, especially comprise phthalic anhydride, trimellitic anhydride and succinyl oxide, and wherein trimellitic anhydride is preferred. Described end-capping reagent adds in the described prepolymer, and described esterification continues to the acid number that obtains requirement. Total reaction time is about 10 to 15 hours.

Can use the traditional catalyst such as the dibutyl tin oxide that are used to promote esterification of the catalytic amount of 0.01 to 1% (weight).Described catalyzer can add in the first step or in second step.Can be used for described catalyst for esterification and comprise tin, antimony, titanium and zirconium compounds, comprise pure titanium and derivative thereof, as metatitanic acid four (2-ethylhexyl), metatitanic acid four stearyl, diisopropoxy-two (methyl ethyl diketone) titanium, two n-butoxies-two (trolamine closes) titanium, monoacylphosphine metatitanic acid tri-n-butyl, monoacylphosphine metatitanic acid three isopropyl esters and four titanium benzoate acid esters; The title complex of the complex salt of titanium such as the oxalate of alkaline titanium and malonate, hexafluoro potassium titanate and titanium and hydroxycarboxylic acid such as tartrate, citric acid or lactic acid, catalyzer such as titania/silica co-precipitation and hydration contain alkali titanium dioxide; With corresponding zirconium compounds.

Before beginning, described reaction can add dimethylbenzene/water so that remove the water that generates in the reaction process.Among the embodiment, the mole increment with 0,15,30,50 and 100% is with 1, and ammediol replaces neopentyl glycol.

Multiple mode of carrying out described reaction is arranged, it will be apparent to those skilled in the art that.Dimethylbenzene/water may be seldom used in plant-scale reaction, should be with ester such as dimethyl terephthalate (DMT) (DMT) or dimethyl isophthalate (DMI) beginning.Also can use chloride of acid.

1 of available epoxy linking agent, flow control additive and crosslinking catalyst preparation, ammediol deutero-polyester manufacture powder coating.Can also comprise in the described prescription conventional coloured material (pigment or dyestuff) as titanium dioxide so that as described in coating substrate have the color of requirement.

The Resins, epoxy that is applicable to the present composition generally is at room temperature to be solid-state any Resins, epoxy.Weight in average/the epoxide of described Resins, epoxy (WPE) is in 400 to 1400 scope, and number-average molecular weight is in 800 to 5000 scope.More preferably the WPE of described Resins, epoxy is 500 to 1000, and number-average molecular weight is 1000 to 2000.Described resin can use higher WPE and molecular weight, as long as can and can be processed in blend under the processing temperature in high shear mixer or melt blended machine.

Usually, 1 of described Resins, epoxy, 2-epoxy equivalent (weight) is greater than 1, and preferred about 2 or bigger.Described Resins, epoxy can be saturated or undersaturated, aliphatic, alicyclic, aromatics or heterocycle family.The example that is applicable to Resins, epoxy of the present invention comprises polyglycidyl ether, brominated oxide compound, epoxy-line style phenolic aldehyde or similar polyphenol resin, glycol or the polyglycidyl ether of polyoxyethylene glycol of polyol, polycarboxylic many glycidyl esters.Preferred described Resins, epoxy is the polyglycidyl ether of polyphenol.The polyglycidyl ether of polyphenol can react production by for example epihalohydrin and polyphenol in the presence of alkali.The example of the polyphenol that is suitable for comprises: 2, and two (4-hydroxyphenyl) propane (bisphenol-A) of 2-; 2, two (4-hydroxyl-tert-butyl-phenyl) propane of 2-; 1, two (4-hydroxyphenyl) ethane of 1-; 1, two (4-hydroxyphenyl) Trimethylmethanes of 1-; 2, two (the 4-hydroxyl tert-butyl-phenyl) propane of 2-; Two (2-hydroxyl naphthyl) methane; 1, the 5-dihydroxy naphthlene; With 1, two (4-hydroxyl-3-alkyl phenyl) ethane of 1-.Preferred polyphenol is a bisphenol-A.Preferred Resins, epoxy be with bisphenol-a reaction and weight/epoxy be 450 to 900 2, the diglycidyl ether of two (4-hydroxyphenyl) propane of 2-.The example of the Resins, epoxy that is suitable for comprises senior EPON (trade mark) Resin 828, the product of ShellChemical Company, it be molecular-weight average be 380 and also weight/epoxy in 180 to 195 scopes 2, the diglycidyl ether of two (4-hydroxyphenyl) propane of 2-.Preferred cross-linking agents is EPON Resins 1001F, 1002F and 2002, and they are and senior EPON 828 resins of bisphenol-a reaction that weight/epoxy is 450 to 900.

Mixing mobile control or even paint ideally in described formulation for coating material helps to make the thermosetting coating of coating even.This flow control additive typically comprises acrylic polymers, and is commercially available, promptly available from the MODAFLOW of Monsanto Company, available from the BYK 360P of BYK Mallinkrodt with available from the ACRONAL of BASF.The suitable concentration range of mixing the described flow control additive in the described coating is 0.25 to 2.0% based on the weight of described resin solid, preferably in 0.60 to 1.5% scope.

Can under the situation of not using catalyzer, make described powder coating solidification or crosslinked.But in fact found needs to comprise that catalyzer promotes the crosslinking reaction of described Resins, epoxy and described polyester.Found the process that bakes set up in the too slow and incompatible industry of uncatalyzed speed of reaction.The catalyzer that is fit to comprises the compound that contains amine, as metal-salt, tin and the zn cpds of acid amides, imide, imidazoles, quaternary ammonium salt, microcosmic salt, acid and lipid acid.The specific examples of these catalyzer is TBAC tetrabutylammonium chloride and choline chloride 60.These catalyzer can be used singly or in combination.In addition, because the kind of catalyst system therefor and amount can must carefully be selected the performance to meet the demands with kind and the amount and the condition of cure change of described resin.The suitable concentration range of mixing the described catalyzer in the described coating is 0.01 to 1% based on the weight of described resin solid, preferably in 0.05 to 0.5% scope.

Embodiment

Synthesizing of the polyester of carboxyl-functional

Polyester with the synthetic carboxyl-functional of two-step approach.In the 1st step, make terephthalic acid (TPA), m-phthalic acid (IPA), NPG and PDO in 1 liter of round-bottomed flask, under nitrogen, react the formation prepolymer under 170 to 230 ℃.The 2nd step added trimellitic acid 1,2-anhydride (TMA), and making described esterification continue to acid number is 100 to 110.Total reaction time is about 10 to 15 hours.Make catalyzer with dibutyl tin oxide (0.4%), add dimethylbenzene/water so that remove the water that generates in the reaction process.PDO with 0 to 100% (mole) replaces the composition of the polyester of NPG to be shown in Table 1.

Table 1

The mole of the vibrin of described carboxyl-functional is formed

Group	??CPE00	??CPE15	??CPE30	??CPE50	??CPE100
						NPG/PDO(mol)	??100/0	??85/15	??70/30	??50/50	??0/100
Terephthalic acid (TPA)	??1.376	??1.397	??1.426	??1.461	??1.556
						M-phthalic acid (ITA)	??0.344	??0.349	??0.357	??0.365	??0.349
Neopentyl glycol (NPG)	??1.894	??1.670	??1.369	??1.000	??0.000
						1, ammediol (PDO)	??0.000	??0.251	??0.587	??1.000	??2.116
Trimellitic acid 1,2-anhydride (TMA)	??0.349	??0.348	??0.346	??0.346	??0.343

The preparation of powder coating

Equivalent by carboxyl/epoxy group(ing) is prepared described PDO deutero-polyester manufacture polyester/epoxy hybrid powder coatings with Resins, epoxy.With equivalent be 525-550 from the EPON 1001F resin of Shell ChemicalCompany linking agent as described polyester.EPON 1001F resin has extremely low equivalent in the Resins, epoxy that is purchased.Choline chloride 60 with 0.2% (from Synthron, the Actiron CC-6 of Inc.) is made catalyzer.Also mix in the described coating flow control additive (Modaflow Powder III, Monsanto) and air release agent-bitter almond oil camphor (Uraflow-B, GCA Chemical Corporation).Use R-960 TiO ₂(DuPont) ratio with the pigment/binder of 0.7/1 (weight) prepares coloured powder coating.The composition of final powder coating is shown in Table 2.

Make all the components premix in high-speed mixer make described solid be broken into granule then to guarantee uniform mixing in 2 minutes earlier.Handle the uniform viscous melt of gained intimate mixing deposits yields by twin screw extruder continuously then.Make the extrusion temperature in the 1st district remain on 75 ℃ under 50rpm, the 2nd district remains on 80 ℃.Make the fused extrudate produce frangible product by a pair of water-cooled extrusion roll.Under the situation of described grinding chamber supply liquid nitrogen, described product is pulverized lentamente then with beater grinder.

Final electrostatic powder spraying on the cold-rolled steel sheet (Q Panel QD-36 and S-36) of ground connection, is solidified the performances of the 15 minutes described coating of postevaluation under 190 ℃.Described curing is undertaken by steel plate is placed in the hot air drying oven.

Table 2

The powder coating prescription

Group	??CPE00	??CPE30	??CPE50	???P-CPE00	?P-CPE30
						CPE00	????48.65	????--	????--	????28.55	????--
CPE30	????--	????49.38	????--	????--	????28.98
						CPE50	????--	????--	????49.38	????--	????--
EPON?1001F?Resin	????49.48	????48.75	????48.75	????29.04	????28.61
						DuPont?R-960?TiO 2	????--	????--	????--	????40.31	????40.31
Choline chloride 60	????0.20	????0.20	????0.20	????0.20	????0.20
						ModaflowPowder?III	????1.18	????1.18	????1.18	????1.15	????1.15
Bitter almond oil camphor	????0.49	????0.49	????0.49	????0.75	????0.75
						Total amount	????100	????100	????100	????100	????100

The characteristic of vibrin

Provide and those resin similar performance (table 3) by the vibrin of PDO deutero-carboxyl-functional based on NPG.The second-order transition temperature of described polyester (Tg) is along with the increase of PDO content descend (Fig. 1).For example, described Tg value at 67 ℃ of described NPG polyester to 55 ℃ scope of described 50%PDO polyester.The second-order transition temperature of the polyester of described carboxyl-functional is higher 6 to 8 ℃ than the polyester of corresponding hydroxyl-functional.Estimate that this characteristic of described carboxy(l)polyester improves the stability in storage of corresponding powder coating.The Tg of described polyester by differential scanning calorimetry (DSC) with the scanning speed of 10 ℃/min at reporting for second heating period.Related to described second heating period before measuring described Tg sample is heated to fusion, make described resin cooling then.

By no crystallization or melting peak on the DSC curve of NPG or described NPG/PDO mixture deutero-polyester, expression amorphous polyester (Fig. 2).But by pure PDO deutero-polyester is semi-crystalline polymer, and crystallization and melt temperature are respectively about 112 and 180 ℃.Thereby, partly replace NPG to produce the amorphous polyester that is applicable to application of paints with maximum 50% (mole) PDO.Should notice that described carboxy(l)polyester and described hydroxyl polyester are similar aspect the non-crystalline state characteristic.

Table 3

The character of the polyester of carboxyl-functional

Group	??CPE00	??CPE15	??CPE30	??CPE50	??CPE100
						NPG/PDO(mol)	????100/0	????85/15	????70/30	????50/50	????0/100
Carboxyl equivalent	????529	????534	????545	????545	????530
						Acid number	????106	????105	????103	????103	????105
Mn	????2464	????2579	????2580	????2238	????--
						Polymolecularity	????1.68	????1.85	????1.88	????1.85	????--
Color before grinding	Little Huang	Little Huang	Little Huang	Little Huang	Little Huang

Processibility

Behind the premix, process described homogeneous powdered mixture by twin screw extruder continuously and form uniform viscous melt.Make the extrusion temperature in the 1st district remain on 75 ℃ under 50rpm, the 2nd district remains on 80 ℃.All powdered mixture that formed by NPG and PDO polyester all are easy to by described forcing machine processing (table 4).

Table 4

The processibility of polyester powder coating

Group	????C00	????C30	????C50	????P00	????P30
						Moment of torsion	????73％	????66％	????60％	????79％	????74％
Temperature, the 1st district (℃)	????75	????75	????75	????75	????75
						Temperature, the 2nd district (℃)	????80	????80	????80	????80	????80
Processibility	Good	Good	Good	Good	Good

Stability in storage

The second-order transition temperature that is used for the vibrin of powder coating should be enough high to obtain good preservation stability.What be used for polyester/epoxy hybrid powder coatings is purchased typically have an appointment 50 to 60 ℃ Tg value of polyester.As estimating that using up to 50%PDO deutero-carboxy(l)polyester powder formulated coating has fabulous stability in storage,, they surpass 55 ℃ Tg value because having.

Powder was carried out storage stability test in 10 days in 40 ℃ of following placements in the jar of adding a cover.Examine or check the free-flowing property of described powder or not breakable agglomerate then every day.All samples all have free-flowing property after 10 days.

Swash plate flows

Pressing PCI standard method measurement swash plate flows.It is the indication of the powder coated liquidity that takes place during partly solidified.It is relevant with the zero melt viscosity of cutting of basic resin that described swash plate flows, and influenced by the reactivity of linking agent and described vibrin.Obviously the increase of PDO concentration and increase (table 5) in 175 and 190 ℃ described swash plates flow all along with the PDO/NPG mixture down.For example, for pure NPG, 30% and 50%PDO for, described swash plate flows and to be respectively 50,68 and 79mm.Thereby, mix the flowability that PDO improves described powder coating.The swash plate of described powder is flowing in 175 ℃ down than high under 190 ℃, because temperature is high more, speed of reaction is high more.

The gelation time reactivity

The gelation time reactivity is that powder advances to the gelatinized required time by liquid phase under specified temperature.By on hot plate, carrying out described test until producing solid gel with the tip of the wooden coating machine bar described powder coating that rubs.Press the PCI standard method 180 ℃ of gelation times of measuring polyester powder coating down.As shown in table 5, described coating all has similar gelation time, and is consistent with DSC research.

Table 5

Swash plate flow test result

Group	??C00	??C30	??C50	???P00	????P30
						PDO％	????0	????30	????50	????0	????30
Flow (mm) under 175 ℃	????64	????85	????104	????22	????23
						Flow (mm) under 190 ℃	????50	????68	????79	????13	????15
Gelation time under 180 ℃ (sec)	????280	????270	????290	????340	????320

The reactivity of powder

Scanning speed with 10 ℃/min is studied the polyester polymers of described carboxyl-functional and the reactivity of epoxy resin cross-linking agent by differential scanning calorimetry (DSC).Described DSC curve is shown among Fig. 3, and test-results shown in the table 6 represents that the solidified of these powder coating begins, exothermic peak and enthalpy are very approaching.Therefore, reactive similar based on the polyester of NPG and PDO/NPG mixture and described linking agent.

Table 6

Reactive DSC result of powder

Group	????C00	????C30	????C50
				PDO％	????0	????30	????50
Starting temperature (℃)	????110	????108	????111
				The peak (℃)	????178	????180	????180
Enthalpy (J/g)	????61.61	????60.36	????62.34

Shock-resistance

Measure the pros and cons shock-resistance of described powder coating by ASTM D2794 standard method.Result in the table 7 shows that PDO improves the snappiness of transparent and coloured polyester/epoxy hybrid powder coatings significantly.For example, shock-resistance increases to the 78.08/18.08m.N (160/160in-lbs) of 50%PDO deutero-polyester from the 11.30/7.91m.N (100/70in-lbs) that increases to 30%PDO based on the 5.65/3.39m.N (50/30in-lbs) of the powder coating of pure NPG polyester (just/reverse side) under the thickness of about 0.064mm (2.5mil).In addition, described shock-resistance depends primarily on thickness, and film is thick more, and snappiness is low more.

Table 7

Polyester/epoxy hybrid powder coatings just/the reverse side shock-resistance

Thickness mm (mil)	????C00 m.N(in.lb.)	????C30 ??m.N(in.lb.)	????C50 ??m.N(in.lb.)	????P00 ??m.N(in.lb.)	????P30 ??m.N(in.lb.)
						????0.028-0.030 ????(1.1-1.2)	??--	??--	??--	??5.65/1.36 ??(50/12)	??9.04/3.39 ??(80/30)
????0.038-0.041 ????(1.5-1.6)	??12.43/10.17 ??(110/90)	??16.95/14.69 ??(150/130)	??18.08/18.08 ??(160/160)	??--	??--
						????0.043-0.046 ????(1.7-1.8)	??--	??--	??--	??3.16/0.68 ??(28/6)	??5.65/1.58 ??(50/14)
????0.061-0.064 ????(2.4-2.5)	??5.65/3.39 ??(50/30)	??11.30/7.91 ??(100/70)	??18.08/18.08 ??(160/160)	??--	??--

Gloss

20 ° of described transparent and coloured polyester/epoxide powder coating and 60 ° of gloss are shown among Fig. 4.For Clear paint, mix PDO and obtain the gloss better slightly than pure NPG.The Color paint that contains 30%PDO and 100%NPG polyester has similar gloss number.

The two frictional properties of hardness, viscosity and anti-MEK

All coating of estimating all have fabulous viscosity (table 8) with cold-rolled steel matrix.They are by netted (crosshatch) adhesive tape adhesion test according to ASTM D-3359-92, and test value is 5B, i.e. not failure.Replace NPG to influence final pencil hardness hardly with PDO.Aspect the two frictional properties of anti-MEK, 50%PDO obtains than described 30%PDO and the low slightly value of pure NPG.Thereby, make good hardness of film, impact snappiness and high gloss and fabulous viscosity combines based on the coating of PDO/NPG mixture.

Table 8

The two frictional properties of hardness, viscosity and anti-MEK

Performance	??C00	??C30	??C50	??P00	??P30
						Thickness, mm (mil)	????0.038 ????(1.5)	????0.038 ????(1.5)	????0.041 ????(1.6)	????0.038 ????(1.5)	????0.036 ????(1.4)
Pencil hardness	????HB	????HB	????HB	????2H	????2H
						Viscosity	????5B	????5B	????5B	????5B	????5B
The two frictions of MEK	????50	????50	????46	????75	????75

Chemical resistant properties and stain resistance

Compare with controlled trial and to contact 10%HCl, 10%NaOH, gasoline and 24 hours coating of mustard fabulous acidproof and alkali resistance is arranged.It is minimum to contact after 24 hours the effect of gasoline.All coating all show fabulous anti-mustard contaminative.It seems that described stain resistance is not only relevant with chemical resistant properties, and relevant with the hardness of coating.Soft resin is than the easier pollution of hardened resin.It is very little to pencil hardness and chemical resistant properties influence to observe PDO deutero-coating, thereby does not influence described stain resistance (table 9).Described data provide with the form of rated value, and 10 expressions do not have influence, and 1 expression destroys the most serious.

Table 9

The chemical resistant properties of powder coating and stain resistance

	????C00	????C30	????C50	????P00	????P30
						10％HCl	????10	????10	????10	????10	????10
10％NaOH	????10	????10	????10	????10	????10
						Mustard	????10	????10	????10	????10	????10
Gasoline	????9	????9	????9	????9	????9

Crooked and the T shape pliability test of snappiness-tapering spindle

Carry out the tapering spindle pliability test by in 3 seconds time cycle, going up crooked described coated panel at tapering spindle tester (Gardher Laboratory, Inc.3.2mm (1/8 ") diameter).Test-results is shown in Table 10.All transparent coated panels are all by described test, i.e. leakless.But occur the crack of about 6mm when the bent spindle with the Color paint of pure NPG polyester preparation, and 30%PDO deutero-polyester coatings formulated is by described test.

The snappiness of measuring by described T type pliability test shows that mixing 30%PDO forms 1T coating, and pure NPG obtains the 3T value.The coating that contains 50%PDO has fabulous snappiness, and the OT value is arranged.Under the situation of Color paint, pure NPG obtains the 5T value, obtains the 3T value and mix 30%PDO.Thereby these result datas prove that further PDO improves the flexible contribution of powder coating.

Table 10

Crooked and the T type pliability test result of tapering spindle

	????C00	????C30	????C50	????P00	????P30
						PDO％	??0	??30	??50	??0	??50
Thickness, mm (mil)	??0.038(1.5)	??0.038(1.5)	??0.041(1.6)	??0.038(1.5)	??0.041(1.6)
						1/8 " tapering spindle bending	By	By	By	The 6mm crack	By
The bending of T shape	??3T	??1T	??0T	??5T	??3T

Claims (10)

1. polyester powder coating composition forms by following substance reaction:

A) one or more aliphatic diol and one or more polycarboxylic acid and/or acid anhydride react in the presence of esterifying catalyst then and make the vibrin of described polyester end-blocking to guarantee that described polyester has the carboxyl chain end to form with end-capping reagent, wherein said aliphatic diol comprises 5 to 90 moles of %1, ammediol; With

B) epoxy resin cross-linking agent.

2. the powder paint compositions of claim 1, wherein said 1, ammediol accounts for 10 to 50% of described aliphatic diol.

3. claim 1 or 2 powder paint compositions, the number-average molecular weight of wherein said aliphatic diol is 62 to 500.

4. claim 1,2 or 3 powder paint compositions, wherein said aliphatic diol is selected from 1,3-butyleneglycol, 1,4-butyleneglycol, ethylene glycol, glycol ether, 1,2-propylene glycol, 1,6-hexylene glycol, triglycol, Tetraglycol 99, tripropylene glycol, four propylene glycol, dipropylene glycol, 2-methyl isophthalic acid, ammediol, hydroxyl value are 56 to 168 polycarbonate diol, dimerization Fatty Alcohol(C12-C14 and C12-C18) and neopentyl glycol.

5. the powder paint compositions of claim 4, wherein said aliphatic diol is a neopentyl glycol.

6. arbitrary powder paint compositions of aforesaid right requirement also comprises a spot of branching agent that is selected from TriMethylolPropane(TMP), trimethylolethane and tetramethylolmethane.

7. arbitrary powder paint compositions of aforesaid right requirement, wherein said polycarboxylic acid and/or acid anhydride are selected from saturated, unsaturated, aliphatic and aromatic polycarboxylic acid and/or acid anhydride.

8. the powder paint compositions of claim 7 comprises the polycarboxylic acid and/or acid anhydride or its mixture that are selected from phthalic acid, m-phthalic acid, terephthalic acid, sebacic acid, toxilic acid, fumaric acid, succsinic acid, hexanodioic acid, nonane diacid, propanedioic acid, dodecanedioic acid, trimellitic acid, pyromellitic acid.

9. the powder paint compositions of claim 8 comprises the polycarboxylic acid and/or acid anhydride or its mixture that are selected from m-phthalic acid, terephthalic acid and trimellitic acid.

10. polyester powder coating composition forms by following substance reaction:

A) wherein 1, ammediol accounts for the neopentyl glycol and 1 of 5 to 90% (moles), and terephthalic acid and the mixture of m-phthalic acid of the ratio of the mixture of ammediol and terephthalic acid wherein and m-phthalic acid in 90/10 to 50/50 scope reacts in the presence of dibutyl tin oxide and add the vibrin that trimellitic acid 1,2-anhydride forms described polyester end-blocking then; With

B) epoxy resin cross-linking agent, it be with bisphenol-a reaction and weight/epoxy be 450 to 900 2, the diglycidyl ether of two (4-hydroxyphenyl) propane of 2-.

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