CA1187083A - Blocked polyisocyanate compounds and polyurethane heat-curing coatings containing said compounds - Google Patents
Blocked polyisocyanate compounds and polyurethane heat-curing coatings containing said compoundsInfo
- Publication number
- CA1187083A CA1187083A CA000429843A CA429843A CA1187083A CA 1187083 A CA1187083 A CA 1187083A CA 000429843 A CA000429843 A CA 000429843A CA 429843 A CA429843 A CA 429843A CA 1187083 A CA1187083 A CA 1187083A
- Authority
- CA
- Canada
- Prior art keywords
- radical
- coating material
- polyurethane
- compound
- polyisocyanate compound
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G18/00—Polymeric products of isocyanates or isothiocyanates
- C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
- C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
- C08G18/72—Polyisocyanates or polyisothiocyanates
- C08G18/80—Masked polyisocyanates
- C08G18/8061—Masked polyisocyanates masked with compounds having only one group containing active hydrogen
- C08G18/807—Masked polyisocyanates masked with compounds having only one group containing active hydrogen with nitrogen containing compounds
- C08G18/808—Monoamines
Abstract
ABSTRACT OF THE DISCLOSURE
A polyurethane one-component heat-curing coating material which is stable in storage and is hardened above a temper-ature of about 120°C, comprising a polyol compound having a low glass transition temperature, and a blocked polyisocyanate com-pound, wherein the blocked polyisocyanate compound is the reaction product of a polyisocyanate compound and a secondary amine com-pound having the formula:
A polyurethane one-component heat-curing coating material which is stable in storage and is hardened above a temper-ature of about 120°C, comprising a polyol compound having a low glass transition temperature, and a blocked polyisocyanate com-pound, wherein the blocked polyisocyanate compound is the reaction product of a polyisocyanate compound and a secondary amine com-pound having the formula:
Description
~37~83 This invention relates to the use of specially blocked polyisocyanates having a latent isocyanate (NCO) content as a hardener of polyols.
Blocked polyisocyanates axe used in the production of thermosetting l-K-PUR baking systems which are stable in storage at room temperature. A mixture of a polyisocyanate and a polyol is only stable in storage at room temperature and is only workable at a higher temperature with pigments and other additives if the reactive NCO groups are blocked and, hence, are unable to react.
In the hardening stage, the blocking agents must, of course, be able to split off.
The masking or blocking of polyisocyanates is a procedure which has long been known for the temporary protection of NCO groups. The production of such masked isocyanates, is described, for example, in Houben Weyl, "Methods of Organic Chemistry"~ XIV/2, pages 61-70. The literature cites various blocking agents, for example, tertiary alcohols, phenols, aceto-~cetic ester, ethyl malonate, acetyl acetone, phthalimide, imidazole, hydrochloric acidr and hydrocyanic acid. Also described are ~-caprolactam and phenol, which have achieved technical importance. Such isocyanates blocked with -caprolactam and phenol are described in DE-OS 21 66 423. The masked isocyanates have the property of reacting like isocyanates at an elevated temperature. The greater the acidity of the hydrogen atom of the masking group, the easier the blocking agent will split o~f.
However, a serious disadvantage in the use of phenols `;~
37~13 or ~-caprolactam as blocking agents is, for a number of applica-tions, the relatively high temperature required for spl.itting off. Fox most polyisocyanates, the splitting temperature required when using these two blocking agents is at least 140C or more.
There is great interes~ in polyisocyanates which deblock at lower temperatures.
It is an object of the present invention to provide a polyurethane one-component heat-curing coating material made of a polyol and a blocked polyisocyanate, which is stable in storage, but which may be hardened at temperature above 120 C.
Accordingly the present invention provides a poly-urethane heat-curing coating material which is stable in storage and is hardened above a temperature of about 120C, which comprises a polyol compound having a low glass transi-tion temperature, and a blocked polyisocyanate compound, wherein said blocked polyisocyanate compound is the reaction product o:E a polyisocyanate compound and a secondary amine compound having the formula:
H~
wherein R is selected from the group consisting of hydrogen atom, C3-Cg alkyl radical, unsubstituted cycloalkyl radical, cycloalkyl radical substituted by Cl-C4 alkyl radicals, heteroatom-containing cycloalkyl radical, unsubstituted aralkyl radical, aralkyl radical substituted by Cl-C4 alkyl radicals, or heteroatom-containing aralkyl radical, wherein each R is identical ~8~7~83 to or different from each other; Rl is selected from the group consisting of alkyl radical, cycloalkyl radical, or aralkyl radical, wherein each Rl is identical to or different from each other; or R and Rl are chemically bonded therebetween, thereby forming a ring structure.
The coating material can be applied as one component.
Surprisingly, it has now been discovered that it is possible to produce r in a simple manner, blocked polyisocyanates that may be deblocked at considerably lower temperatures than the isocyanates masked with the customary blocking agents, if certain secondary amines are used for the production of the blocked polyisocyanates. The polyurethane one-component heat-curing coating material of the present invention is made of a polyol and a blocked polyisocyanate, wherein the blocked polyisocyanate is a reaction product of a polyisocyanate and a secondary amine having the formula:
HN /
\ CR3 wherein R may be a hydrogen atom, C3-Cg alkyl, unsubstituted cycloalkyl, cycloalkyl substltuted by Cl-C4 alkyl, heteroatom-containing cycloalkyl, unsubstituted aralkyl, aralkyl substitutedby Cl-C4 alkyl or heteroatom-containing aralkyl radicals, wherein each R may be identical to or different from each other; Rl is an alkyl, cycloalkyl, or aralkyl radical, wherein each Rl may be identical to or different from each other; and R and Rl may form a common ring structure. In forming the blocked polyisocyanates ~8'7d~83 of the present invention, 0.5 to 1 mole of secondary amine may be used for one isocyanate group; however, it is preferable to use 0.8 to 1 mole of secondary amine for one isocyanate group.
It is surprising that amines, secondary as well as primary, have not been described as blocking agents for polyisocyanates in the literature. There are a n~ber of United States patents wherein ureas derived from mono- and diisocyanates and primary or secondary amines are described as epoxy resin hardeners, for example United States Patents 3,227,679, 3,317,612;
3,321,549; 3,789,071; 3,407,175; and 3,956,237. In this process, the hardening takes place for the most part through a reaction of the urea group with the epoxide group, with an oxaæolidinone ring being formed. However, there are no references in the literature, at splitting temperatures below 200C, pertaining to ureas derived from polyisocyanates and secondary amines as heat-curing hardeners or polyols. It must be stressed that not all secondary amines are suitable for the production of the compounds appropriate to the invention. The amines that may be used according to the invention must provide steric hindrance; thus, for example, di-n-propylamine, in contrast to di-isopropylamine, is not suitable as a blocking agent because -the polyurethanes produced with di-n-propylamine are too stable. The greater the steric hindrance of the secondary amine -- more precisely, the steric shielding of the H atom bound to the N -- the lower the splitting temperature of the polyisocyanate blocked therewith.
The following are suitable as initial compounds ~hich may be blocked with the secondary amines according to the present ~B7~83 in~ention: polyisocyanates, especially diisocyanates such as aliphatic, cycloaliphatic, araliphatic, aryl-substituted aliphatic and/or aromatic diisocyanates, as they are described, ~or example, in Houben-Weyl~ "Methods of Organic Chemistry", Volume XIV/2, pages 61-70, and in the article o~ W. Sie~ken in "Justus Liebigs Annalen der Chemie" 562, pages 75-136, including such compounds such as 1,2-ethylene diisocyanate, 1,4-tetra-methylene diisocyanate, 1,6-hexamethylene diisocyanate, ~,2,4- or
Blocked polyisocyanates axe used in the production of thermosetting l-K-PUR baking systems which are stable in storage at room temperature. A mixture of a polyisocyanate and a polyol is only stable in storage at room temperature and is only workable at a higher temperature with pigments and other additives if the reactive NCO groups are blocked and, hence, are unable to react.
In the hardening stage, the blocking agents must, of course, be able to split off.
The masking or blocking of polyisocyanates is a procedure which has long been known for the temporary protection of NCO groups. The production of such masked isocyanates, is described, for example, in Houben Weyl, "Methods of Organic Chemistry"~ XIV/2, pages 61-70. The literature cites various blocking agents, for example, tertiary alcohols, phenols, aceto-~cetic ester, ethyl malonate, acetyl acetone, phthalimide, imidazole, hydrochloric acidr and hydrocyanic acid. Also described are ~-caprolactam and phenol, which have achieved technical importance. Such isocyanates blocked with -caprolactam and phenol are described in DE-OS 21 66 423. The masked isocyanates have the property of reacting like isocyanates at an elevated temperature. The greater the acidity of the hydrogen atom of the masking group, the easier the blocking agent will split o~f.
However, a serious disadvantage in the use of phenols `;~
37~13 or ~-caprolactam as blocking agents is, for a number of applica-tions, the relatively high temperature required for spl.itting off. Fox most polyisocyanates, the splitting temperature required when using these two blocking agents is at least 140C or more.
There is great interes~ in polyisocyanates which deblock at lower temperatures.
It is an object of the present invention to provide a polyurethane one-component heat-curing coating material made of a polyol and a blocked polyisocyanate, which is stable in storage, but which may be hardened at temperature above 120 C.
Accordingly the present invention provides a poly-urethane heat-curing coating material which is stable in storage and is hardened above a temperature of about 120C, which comprises a polyol compound having a low glass transi-tion temperature, and a blocked polyisocyanate compound, wherein said blocked polyisocyanate compound is the reaction product o:E a polyisocyanate compound and a secondary amine compound having the formula:
H~
wherein R is selected from the group consisting of hydrogen atom, C3-Cg alkyl radical, unsubstituted cycloalkyl radical, cycloalkyl radical substituted by Cl-C4 alkyl radicals, heteroatom-containing cycloalkyl radical, unsubstituted aralkyl radical, aralkyl radical substituted by Cl-C4 alkyl radicals, or heteroatom-containing aralkyl radical, wherein each R is identical ~8~7~83 to or different from each other; Rl is selected from the group consisting of alkyl radical, cycloalkyl radical, or aralkyl radical, wherein each Rl is identical to or different from each other; or R and Rl are chemically bonded therebetween, thereby forming a ring structure.
The coating material can be applied as one component.
Surprisingly, it has now been discovered that it is possible to produce r in a simple manner, blocked polyisocyanates that may be deblocked at considerably lower temperatures than the isocyanates masked with the customary blocking agents, if certain secondary amines are used for the production of the blocked polyisocyanates. The polyurethane one-component heat-curing coating material of the present invention is made of a polyol and a blocked polyisocyanate, wherein the blocked polyisocyanate is a reaction product of a polyisocyanate and a secondary amine having the formula:
HN /
\ CR3 wherein R may be a hydrogen atom, C3-Cg alkyl, unsubstituted cycloalkyl, cycloalkyl substltuted by Cl-C4 alkyl, heteroatom-containing cycloalkyl, unsubstituted aralkyl, aralkyl substitutedby Cl-C4 alkyl or heteroatom-containing aralkyl radicals, wherein each R may be identical to or different from each other; Rl is an alkyl, cycloalkyl, or aralkyl radical, wherein each Rl may be identical to or different from each other; and R and Rl may form a common ring structure. In forming the blocked polyisocyanates ~8'7d~83 of the present invention, 0.5 to 1 mole of secondary amine may be used for one isocyanate group; however, it is preferable to use 0.8 to 1 mole of secondary amine for one isocyanate group.
It is surprising that amines, secondary as well as primary, have not been described as blocking agents for polyisocyanates in the literature. There are a n~ber of United States patents wherein ureas derived from mono- and diisocyanates and primary or secondary amines are described as epoxy resin hardeners, for example United States Patents 3,227,679, 3,317,612;
3,321,549; 3,789,071; 3,407,175; and 3,956,237. In this process, the hardening takes place for the most part through a reaction of the urea group with the epoxide group, with an oxaæolidinone ring being formed. However, there are no references in the literature, at splitting temperatures below 200C, pertaining to ureas derived from polyisocyanates and secondary amines as heat-curing hardeners or polyols. It must be stressed that not all secondary amines are suitable for the production of the compounds appropriate to the invention. The amines that may be used according to the invention must provide steric hindrance; thus, for example, di-n-propylamine, in contrast to di-isopropylamine, is not suitable as a blocking agent because -the polyurethanes produced with di-n-propylamine are too stable. The greater the steric hindrance of the secondary amine -- more precisely, the steric shielding of the H atom bound to the N -- the lower the splitting temperature of the polyisocyanate blocked therewith.
The following are suitable as initial compounds ~hich may be blocked with the secondary amines according to the present ~B7~83 in~ention: polyisocyanates, especially diisocyanates such as aliphatic, cycloaliphatic, araliphatic, aryl-substituted aliphatic and/or aromatic diisocyanates, as they are described, ~or example, in Houben-Weyl~ "Methods of Organic Chemistry", Volume XIV/2, pages 61-70, and in the article o~ W. Sie~ken in "Justus Liebigs Annalen der Chemie" 562, pages 75-136, including such compounds such as 1,2-ethylene diisocyanate, 1,4-tetra-methylene diisocyanate, 1,6-hexamethylene diisocyanate, ~,2,4- or
2,4,4-trimethyl-1,6-hexamethylene diisocyanate (TMDI), 1,12-dodecane diisocyanate, W,Wl-diisocyanate dipropylether, cyclobutane-l, 3-diisocyanate, cyclohexane-1,3- and 1,4-diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, which is also called isophorone diisocyanate and is also abbreviated as IPDI, decahydro-8-methyl-(1,4-me-thano-naphthalene-2 (or 3) 5-ylene dimethylene diisocyanate, decahydro-4,7-metha-no-inda 1 (or 2) 5 (or 6)-ylene dimethylene diiso-cyanate, hexahydro-4-7-methane indan-l (or 2) 5 (or 6)-ylene diisocyanate, hexahydro-1,3- or 1,4-phenylene diisocyanate, 2,4-and 2,6-hexahydrotoluene diisocyanate, perhydro-2,4l-and/or-4,4'-diphenyl methane diisocyanate, W,~l-diisocyanate-1,4-diethyl benzene, 1,4-phenylene diisocyanate, 4,4'-diisocyanate diphenyl, 4,4'-diisocyana-te-3,3'-dichlorodiphenyl, 4,4'-diisocyanate-3,3'-dimethoxyd-phenyl, 4,4'-diisocyanate-3,3'-dimethyldiphenyl, 4,4' diisocyanate-3,3'-diphenyldiphenyl, 4,4'-diisocyanate-diphenylmethane, naphthylene-1,5-diisocyanate, toluene diisocyanate, toluylene-2,4- or 2,6-diisocyanate, N,N'-(4,4'-dimethyl-3,3'-diisocyanate diphenyl)-uretdione, m-xylylene ~87i~83 diisocyanate, but also the triisocyanates such as 2,4,4-tri-isocyanate diphenylether, 4,4',~"-triisocyanatetriphenylmethane, tris(4-isocyanate phenyl~-thi.ophosphate. Additional suitable isocyanates are described in the above-mentioned article in the "Annalen" on page 122 ff.
Particularly preferred are the commercially a~ailable aliphatic, cycloaliphatic and aromatic diisocyanates and especiall~ 3-isocyanatomethyl-3,5,5-trimeth~lcyclohexylisocyanate and toluene diisocyanate and their isomer mixturesO
In addition to the monomer polyisocyanates, the dimer and trimer forms of the polyisocyanates, such as uretdiones and isocyanurates can, o~ course/ also be used. The latter two can be produced according to well-known methods.
The polyisocyanates which may be used according to this invention also include those which prior to blocking with the secondary amines are subjected to a reaction to increase the size of the molecule with so-called chain extending agents customary in isocyanate chemistry, such as, for example, polyols, whereby the bi- or trifunctional chain extending agents, that is, those with groups capable of reacting with isocyanate groups, such as, for example, hydroxyl-group-bearing compounds, are used in such quantities that the resulting new isocyanate carries at least two isocyanate groups.
Suitable polyols which may be used as chain extending agents, are, for example, diols and triols, such as ethylene glycol, propylene glycol, 1,2- and 1,3-propane diol and 2,2-dimethy].propane diol-(1,3); butanediols, such as butanediol-(1,4~;
~8~33 hexanediols, such as hexanediol-(1,6), 2,2,4-trimethylhexanedio-(1,6), 2,4,4-trimethylhexanediol-(1,6); and heptanediol-(1,7), octadecene-9, 10-diol-(1,12), thiodiglycol, octadecanediol-(1,18), 2,4-dimethyl-2-propylheptanediol~ ), butene- or butinediol-(1,~), diethylene glycol, triethylene glycol, trans- and cis-1,4-cyclohexanedimethanol, l,~-cyclohexanediols, glycerin, hexanetriol-1,2,6), l,l,l-trimethylolpropane, and l,l,l-trimethyl-olethane. Mixtures of the above-mentioned compounds may also be used.
The reaction of the polyisocyanates, prior to blocking, with the mentioned chain extending agents in the cited proportions can be carried out at temperatures ranging from 0 to 150C, preferably at 80-120C.
Suitable secondary amines which may be used according to this invention which are in accordance with the formula described earlier are, for example, diisopropylamine, isopropyl--tert.-butylamine,-dicyclohexylamine, di~(3,5,5-trimethylcyclo-hexyl) amine, 2,6-dimethylpiperidine, 2,5-dime-thylpyrrolidine, 2,2,6~6-tetramethylpiperidine, 2,2,4,6-tetramethylpiperidine, isopropylcyclohexylamine, and others. Mixtures of the secondary amines appropriate to the invention may also be used.
The reaction of the polyisocyanates with secondary amines may be performed with solvents as well as by melting. If a solvent is used, the amount of the secondary amine added to the polyisocyanate heated to 70-120C is such that the temperature of the reaction mixture does not exceed 130C. After all of the blocking agent has been added, the reaction mixture continues to 7~83 be heated for about another hour at about 100-120C to complete the reaction.
While the blocking may be carried out using solvents, the solvents must not react with polyisocyanates. Examples of such solvents are ketones, such as acetone, methylethylketone, methylisobutyl~etone~ cyclopentanone, cyclohexanone; aromatics, such as benzene, toluol, cyclols, chlorobenzene, nitrobenzene;
cyclic ethers, such as tetrahydrofuran, dioxane; chlorinated hydrocarbons, such as chloroform, carbon tetrachloride; and aprotic solvents, such as dimethylformamide, dimethylacetamide, and dimethylsulfoxide.
The adducts thus obtained, in general, are compounds having a molecular weight of 300-2500~ preferably 300-1000. The process products have a melting temperature range of 30-220C, preferably 80-160C. The polyisocyanates blocked with the secondary amines are further characterized by containing isocyanate groups in final blocked form (calculated as NCO) of 4-25~ by weight, preferably 10 21% by weight~
The process products are especially suitable as hardeners for higher functional compounds having Zerewitinoff-active hydrogen atoms~ In combination with compounds having Zerewi-tinoff-active hydrogen atoms, the process products form, above 120C, preferably 130-200C, systems hardenable into high-~rade plastics.
The most important field of application for the compounds according to this invention is their use as a bonding agent for solvent-containing l-K-PUR coating.
7~83 Suitable reactants with the process products for the production of such heat~hardenable systems are compounds contain-in~ at least two hydroxyl or amino groups. The use of polyhydroxyl compounds, especially those with a molecular weight o~ 400-2000, is preferred. These O~-containing compounds are polyesters, polyethers, polyacetals, polyesteramides, and polyepoxides, preferably containing 2-6 hydroxyl groups.
The hydroxyl-containing polyesters according to the invention must have a low glass transition temperature; it should be below 20C and above -25C. Significant component polyesters are:
1~ Cyclic polycarboxylic acids and their esters and anhydrides, for example, phthalic acid, isophthalic acid, terephthalic acid, benzene, 1,2,4-tricarboxylic acid, trimellitic acid anhydride, dimethylterephthalate (DMT) and their hydrogena-tion products.
2) Diols, for example, ethylene glycol, 1,2-propanediol, 1,2- or 1,3- or 1,4-bu-tanediol, 2,2-dimethylpropanediol, 3-methyl-pentanediol-1,5, hydroxypivalic acid neopentyl glycol ester, hexanediol-1,6, cyclohexane diol, 4~4-dihydroxydicyclohexyl propane-2,2, 1,4-dihydroxymethylcyclohexane, diethelene ~1YCQ1, and triethylene glycol.
Particularly preferred are the commercially a~ailable aliphatic, cycloaliphatic and aromatic diisocyanates and especiall~ 3-isocyanatomethyl-3,5,5-trimeth~lcyclohexylisocyanate and toluene diisocyanate and their isomer mixturesO
In addition to the monomer polyisocyanates, the dimer and trimer forms of the polyisocyanates, such as uretdiones and isocyanurates can, o~ course/ also be used. The latter two can be produced according to well-known methods.
The polyisocyanates which may be used according to this invention also include those which prior to blocking with the secondary amines are subjected to a reaction to increase the size of the molecule with so-called chain extending agents customary in isocyanate chemistry, such as, for example, polyols, whereby the bi- or trifunctional chain extending agents, that is, those with groups capable of reacting with isocyanate groups, such as, for example, hydroxyl-group-bearing compounds, are used in such quantities that the resulting new isocyanate carries at least two isocyanate groups.
Suitable polyols which may be used as chain extending agents, are, for example, diols and triols, such as ethylene glycol, propylene glycol, 1,2- and 1,3-propane diol and 2,2-dimethy].propane diol-(1,3); butanediols, such as butanediol-(1,4~;
~8~33 hexanediols, such as hexanediol-(1,6), 2,2,4-trimethylhexanedio-(1,6), 2,4,4-trimethylhexanediol-(1,6); and heptanediol-(1,7), octadecene-9, 10-diol-(1,12), thiodiglycol, octadecanediol-(1,18), 2,4-dimethyl-2-propylheptanediol~ ), butene- or butinediol-(1,~), diethylene glycol, triethylene glycol, trans- and cis-1,4-cyclohexanedimethanol, l,~-cyclohexanediols, glycerin, hexanetriol-1,2,6), l,l,l-trimethylolpropane, and l,l,l-trimethyl-olethane. Mixtures of the above-mentioned compounds may also be used.
The reaction of the polyisocyanates, prior to blocking, with the mentioned chain extending agents in the cited proportions can be carried out at temperatures ranging from 0 to 150C, preferably at 80-120C.
Suitable secondary amines which may be used according to this invention which are in accordance with the formula described earlier are, for example, diisopropylamine, isopropyl--tert.-butylamine,-dicyclohexylamine, di~(3,5,5-trimethylcyclo-hexyl) amine, 2,6-dimethylpiperidine, 2,5-dime-thylpyrrolidine, 2,2,6~6-tetramethylpiperidine, 2,2,4,6-tetramethylpiperidine, isopropylcyclohexylamine, and others. Mixtures of the secondary amines appropriate to the invention may also be used.
The reaction of the polyisocyanates with secondary amines may be performed with solvents as well as by melting. If a solvent is used, the amount of the secondary amine added to the polyisocyanate heated to 70-120C is such that the temperature of the reaction mixture does not exceed 130C. After all of the blocking agent has been added, the reaction mixture continues to 7~83 be heated for about another hour at about 100-120C to complete the reaction.
While the blocking may be carried out using solvents, the solvents must not react with polyisocyanates. Examples of such solvents are ketones, such as acetone, methylethylketone, methylisobutyl~etone~ cyclopentanone, cyclohexanone; aromatics, such as benzene, toluol, cyclols, chlorobenzene, nitrobenzene;
cyclic ethers, such as tetrahydrofuran, dioxane; chlorinated hydrocarbons, such as chloroform, carbon tetrachloride; and aprotic solvents, such as dimethylformamide, dimethylacetamide, and dimethylsulfoxide.
The adducts thus obtained, in general, are compounds having a molecular weight of 300-2500~ preferably 300-1000. The process products have a melting temperature range of 30-220C, preferably 80-160C. The polyisocyanates blocked with the secondary amines are further characterized by containing isocyanate groups in final blocked form (calculated as NCO) of 4-25~ by weight, preferably 10 21% by weight~
The process products are especially suitable as hardeners for higher functional compounds having Zerewitinoff-active hydrogen atoms~ In combination with compounds having Zerewi-tinoff-active hydrogen atoms, the process products form, above 120C, preferably 130-200C, systems hardenable into high-~rade plastics.
The most important field of application for the compounds according to this invention is their use as a bonding agent for solvent-containing l-K-PUR coating.
7~83 Suitable reactants with the process products for the production of such heat~hardenable systems are compounds contain-in~ at least two hydroxyl or amino groups. The use of polyhydroxyl compounds, especially those with a molecular weight o~ 400-2000, is preferred. These O~-containing compounds are polyesters, polyethers, polyacetals, polyesteramides, and polyepoxides, preferably containing 2-6 hydroxyl groups.
The hydroxyl-containing polyesters according to the invention must have a low glass transition temperature; it should be below 20C and above -25C. Significant component polyesters are:
1~ Cyclic polycarboxylic acids and their esters and anhydrides, for example, phthalic acid, isophthalic acid, terephthalic acid, benzene, 1,2,4-tricarboxylic acid, trimellitic acid anhydride, dimethylterephthalate (DMT) and their hydrogena-tion products.
2) Diols, for example, ethylene glycol, 1,2-propanediol, 1,2- or 1,3- or 1,4-bu-tanediol, 2,2-dimethylpropanediol, 3-methyl-pentanediol-1,5, hydroxypivalic acid neopentyl glycol ester, hexanediol-1,6, cyclohexane diol, 4~4-dihydroxydicyclohexyl propane-2,2, 1,4-dihydroxymethylcyclohexane, diethelene ~1YCQ1, and triethylene glycol.
3) Polyols, such as glycerin, hexanetriol, penta-erythrite, trimethylolpropane, and trimethylolethane.
Proportionately, the polyesters may also contain monofunctional carboxylic acids, for example, benzoic acid, as well as acyclic polycarboxylic acids such as adipic acid, 2,2,4-(2,4,4) trimethyladipic acid, sebacic acid or dodecane 9 _ ,~., ~37~83 dicarboxylic acid. The polyesters are produced in the well-known manner by esterification or interchange of ester radicals possibly in the presence o~ the usual catalysts. Through the appropriate choice of the COOH/OH ratio~ end products are attained whose hydroxyl number is between 40 and 240, but preferably between 70 and 150.
Solvents whose lower boiling point is approximately 100C are suitable for use with the one-component heat-curing coating material according to the present invention. The upper limit of the boiling point o~ the solvent intended for use depends on the prevailing baking conditions. If the baking is done at higher temperatures, then the boiling points of the solvents to be used must lie at higher temperatures. The following compounds, ~mony others, may be used as solvents: hydrocarbons, such as toluol, xylol, solvesso 150 la Shell solvent mixture), tetralin, cumene; ketones, such as methyl isobutyl ketone, diisobutyl ketone, isophorone; and esters, such as acetic acid-n-hexylester, acetic acid butylester, ethylene glycol acetate (EGA), and butyl glycol acetate. The above-mentioned compounds may also be used in mixtures. The concentration of the resin (oxyester)/hardener mixture in the mentioned solvents lies between ~0 and 70% by weight.
The one-component heat-curing coating material according to this invention may be produced in suitable mixing aggregates, for example in vessels having a stirrer, by simply mixing the three lacquer components (high-boiling-point solvent, polyester, and blocked polyisocyanate~ at 80-100 C.
`:
~8~7~83 Further customary additives, such as pigments, flow improvers, gloss improvers, antioxidants and heat stabilizers may also be added to the coating solution. The one-component coating materials are especially suitable for application to metal surfaces; however, they can also be applied to objects made of other materials~ such as glass or plastics. The coating materials according to this invention are primarily applicable to the coil-coating industry for outdoors weather-resisting one-and-two-layer coatings.
The hardening of the coating material according to this invention occurs, depending on applica~ion, in a temperature range of 1~0-350C t preferably between 130 and 300C during a period from 30 minutes to 30 seconds. The hardened coatings have excellent coating properties.
It is known that the hardening of PUR coatings in the presence of amines ~eads to yellowing. Therefore, it is surprising that no ~iscolouration occurs during the hardening of the heat-curing coating of the present invention.
The present invention will be further illustrated by certain examples and references which are provided for purposes of illustration only and are not intended to limit the present invention.
I. Production of Bloc~ed Polyisocyanates -Example 1 724 parts by weight of dicyclohexylamine were added drop-by-drop to 444 parts by weight of isophorone diisocyanate (IPDI) at 120C, so that the temperature of the reaction mixture 1~7~83 did not exceed 140C. After the dicyclohexylamine had been added, heating at 130C was continued for about one hour to complete the reaction.
~ he reaction product had a melting point of 105-110 C
and a 14.38% content of blocked NCO; free amine was no longer detectable.
Example 2 In a manner similar to the process described in Example 1, 226 parts by weight of 2,6-dimethylpiperidine were added to 222 parts by weight IPDI at 130C. After the 2,6-dimethylpiperidine had been added, hea~ing at 130C was continued for about another hour to complete the reaction.
The reaction product had a melting point of 99-103C
and an 18.7% content of blocked NCO; free amine was no longer detectable.
Example 3 101 parts by weight of diisopropylamine were added drop-by-drop at room temperature over approximately 2 hours to 111 parts by weight of IPDI that had been dissolved in 500 parts by weight of anhydrous acetone. After the diisopropylamine had been added, heating at 50C was continued for 2 hours. There-after, the acetone was removed by distillation; the last traces of acetone ~ere removed in the vacuum drier at 60C and 1 torr.
The reaction product had a melting point of 65-74C and a 19.8%
content of blocked NCO.
Example 4 530 parts by weight of di-(3,5,5-trimethyl~-cyclohexyl-amine were added drop-by-drop over a period of about 2 hours to . ~
:
~3~8'7~83 222 parts by weight of IPDI. After all the amine had been added,heatin~ of the reaction mixture was continued at 130C for another 2 hours. The reaction product had a melting point of 84-91C and an 11.1% content of blocked NCO.
Example 5 2S2 parts by weight o~ 2,2,4,6-tetramethylpiperidine were added drop-by-drop over a period of approximately 2 hours to 222 parts by weight of IPDI at 130 C. After the 2,2,4,6-tetramethylpiperidine had been added, heating of thQ reaction mixture at 130C was continued for approximately 1 hour.
The reaction product had a melting point of 120-125C
and a 16.6% content of b~ocked NCO. In contrast to the compounds in Examples 1-4, the amine used for blocking was quantitat.ively detected within about 2 hours, by titration with aqueous ~Cl.
Thus the IPDI hlocked with 2,2,4,6-tetramethylpiperidine is not hydrolysis resistant.
Example 6 202 parts by weight of diisopropylamine were added drop-by-drop within 2 hours to 168 parts by weight of hexamethyl-ene diisocyanate at 130C. After all the diisopropylamine hadbeen added, heating of the reaction mixture at 130C was continued for about 1 hour~ The reaction product had a melting point o~ 130-140C and a 22.7% content of blocked NCO.
Example _ 41.~ parts by weight of diisopropylamine were added at 100C over about 3 hours to 100 parts ~y weight of IPDI-T
1890 (trimer IPDI; product of the Chemische Werke Huels~ with a 17.2% NCO content that had been dissolved in 100 parts by weight of xylol/ethyl glycol acetate (weight ratio: 2:1). Thereafter, heating was continued for 2 hours. The solution thus obtained had a viscosi~y of 261 mPas at room temperature. The content of blocked NCO was 7.1%.
II. Reactivity of the Compounds To examine the reactivity of a polyisocyanate, blocked with an amine, with a polyol, the polyisocyanate was kneaded in a kneading chamber with a polyol at a ratio of (NCOblock:OH = 1:1) at various temperatures and the resistance to kneading was followed as a function of time. The resistance to kneading increased to the same extent as the reaction occurred. When cross-linking occurred, the resistance to kneading rose sharply followed by an abrupt drop. The cross-linked product was finely ground and then offered only slight resistance. The polyiso-cyanate used was a diisocyanate. The results are shown in Table 1.
.
~8~7~3 Table J
Hardeners _neading Behaviour of Hardenrs/Oxyester P 1137 (NCO : OH = 1 : 1) at 120 C 160 C 1~0 C
IPDI blocked with piperidine - no cross- -linking IPDI blocked with 2,6 dimethylpiperidine cross-linked cross-linked after 10 after 4 minutes minutes IPDI blocked with 2,2,4,6-tetramethyl-piperidine immediately cross-linked IPDI blocked with caprolactam cross-linked after 18 minutes P 1137: Oxyester with an OH number of 106-114 and a melting range of from 70-90C (product of the Chemische Werke Huels) III. Appllcation Examples Application Example 1 A) Polyester containing hydroxyl groups (production) 7 moles of isophthalic acid (1.163 g~/ 6 moles of hexanediol-1,6 (709 g) and 2 moles of l,l,l-trimethylolpropane (268 g) were esterified in a 4-liter glass flask with the admixture of 0.1% by weight of n-dibutyltin oxide. With rising temperature, a homogenous batch developed. At about 195C, the first separation of water occurred. Within 8 hours, -the tempera-ture was raised to 220C and at this temperature the ester;fication was completed during the subsequent 6 hours. The :~8'7~83 acid number was smaller than 1 mg KOH/g. After the polyester batch had been cooled down to 200C, the volatile components were removed in a vacuum of 20-30 mm Hg during 30-45 minutes.
During the entire reaction, a weak N2-flow was directed through the xeaction systemO
Chemical and physical characteristics data of the polyester:
OH number 105 mg KOH/g Acid number <1 mg KOH/g Mole weight 2400 Glass transition temperature -12C to +5C
B) Blocked isocyanate components The polyisocyanate described in production Example 3 was used.
C) PUR heat-curing coating -100 g of the polyester obtained in part A of this application example are mixed and dissolved with 398 g of the blocked polyisocyanate of production Example 3, in 466 g n-butylacetate and 446 g xylol solvents at 40-50C to form a resin solution. In the customary fashion, a heat-hardening white coating was formulated according to the following composi-tion 65% by weight of the above-described resin solution;
3% by weight of n-butyl glycol acetate;
2% by weight of iosphorone;
2808% by weight of a white pigment (Tio2);
2% by weight of a 10% solution of a soluble flow ~87~83 improver in ethylglycol acetate; on the basis of an organo-functional silicone oil, and 0.2% by weight dibutyltin dilaurate.
An aluminum sheet was coated with the described coating and hardening was undertaken under varying conditions.
The test results are presented in Table 2.
Table 2 .
E~ardening Condition Coating Testing .
_ PE~ ET GS G20 G45 G60 MEK Test Yellowing min 110C 40 153 0.5 1 90 60 96 60 none min 120C 30 179 7.8 0 87 56 96 >200 none min 1400C 35 181 6.5 0 90 55 94 >200 none 0.75 min 300 C 25 174 8.5 0 69 56 92 >200 none Explanation of symbols:
SD: coating thickness in llm PH: Koenig pendulum hardness, DIN 53 157 ET: Erichsen cupping, DIN 53 156 GS: Cross-cut adhesion test, DIN 53 151 G: gloss according to Gardner ASTMD 523 The test data shown in Table 2 illustrate that quantitative cross-linking/hardening is possible with the above-described coating material starting from about 120C.
Surprisingly, no yellowing occurs d~spite the aminic blocking agent.
1~8~
Application Example 2 A) Polyester containing hydroxyl groups (production) Analogously to the process described in application Example lA, a polyester containing hydroxyl groups was produced.
The following raw materials were used:
moles isophthalic acid (1661 g) 5~5 moles hexanediol-1,6 (650 g) 2.0 moles diethylene glycol (212 g)
Proportionately, the polyesters may also contain monofunctional carboxylic acids, for example, benzoic acid, as well as acyclic polycarboxylic acids such as adipic acid, 2,2,4-(2,4,4) trimethyladipic acid, sebacic acid or dodecane 9 _ ,~., ~37~83 dicarboxylic acid. The polyesters are produced in the well-known manner by esterification or interchange of ester radicals possibly in the presence o~ the usual catalysts. Through the appropriate choice of the COOH/OH ratio~ end products are attained whose hydroxyl number is between 40 and 240, but preferably between 70 and 150.
Solvents whose lower boiling point is approximately 100C are suitable for use with the one-component heat-curing coating material according to the present invention. The upper limit of the boiling point o~ the solvent intended for use depends on the prevailing baking conditions. If the baking is done at higher temperatures, then the boiling points of the solvents to be used must lie at higher temperatures. The following compounds, ~mony others, may be used as solvents: hydrocarbons, such as toluol, xylol, solvesso 150 la Shell solvent mixture), tetralin, cumene; ketones, such as methyl isobutyl ketone, diisobutyl ketone, isophorone; and esters, such as acetic acid-n-hexylester, acetic acid butylester, ethylene glycol acetate (EGA), and butyl glycol acetate. The above-mentioned compounds may also be used in mixtures. The concentration of the resin (oxyester)/hardener mixture in the mentioned solvents lies between ~0 and 70% by weight.
The one-component heat-curing coating material according to this invention may be produced in suitable mixing aggregates, for example in vessels having a stirrer, by simply mixing the three lacquer components (high-boiling-point solvent, polyester, and blocked polyisocyanate~ at 80-100 C.
`:
~8~7~83 Further customary additives, such as pigments, flow improvers, gloss improvers, antioxidants and heat stabilizers may also be added to the coating solution. The one-component coating materials are especially suitable for application to metal surfaces; however, they can also be applied to objects made of other materials~ such as glass or plastics. The coating materials according to this invention are primarily applicable to the coil-coating industry for outdoors weather-resisting one-and-two-layer coatings.
The hardening of the coating material according to this invention occurs, depending on applica~ion, in a temperature range of 1~0-350C t preferably between 130 and 300C during a period from 30 minutes to 30 seconds. The hardened coatings have excellent coating properties.
It is known that the hardening of PUR coatings in the presence of amines ~eads to yellowing. Therefore, it is surprising that no ~iscolouration occurs during the hardening of the heat-curing coating of the present invention.
The present invention will be further illustrated by certain examples and references which are provided for purposes of illustration only and are not intended to limit the present invention.
I. Production of Bloc~ed Polyisocyanates -Example 1 724 parts by weight of dicyclohexylamine were added drop-by-drop to 444 parts by weight of isophorone diisocyanate (IPDI) at 120C, so that the temperature of the reaction mixture 1~7~83 did not exceed 140C. After the dicyclohexylamine had been added, heating at 130C was continued for about one hour to complete the reaction.
~ he reaction product had a melting point of 105-110 C
and a 14.38% content of blocked NCO; free amine was no longer detectable.
Example 2 In a manner similar to the process described in Example 1, 226 parts by weight of 2,6-dimethylpiperidine were added to 222 parts by weight IPDI at 130C. After the 2,6-dimethylpiperidine had been added, hea~ing at 130C was continued for about another hour to complete the reaction.
The reaction product had a melting point of 99-103C
and an 18.7% content of blocked NCO; free amine was no longer detectable.
Example 3 101 parts by weight of diisopropylamine were added drop-by-drop at room temperature over approximately 2 hours to 111 parts by weight of IPDI that had been dissolved in 500 parts by weight of anhydrous acetone. After the diisopropylamine had been added, heating at 50C was continued for 2 hours. There-after, the acetone was removed by distillation; the last traces of acetone ~ere removed in the vacuum drier at 60C and 1 torr.
The reaction product had a melting point of 65-74C and a 19.8%
content of blocked NCO.
Example 4 530 parts by weight of di-(3,5,5-trimethyl~-cyclohexyl-amine were added drop-by-drop over a period of about 2 hours to . ~
:
~3~8'7~83 222 parts by weight of IPDI. After all the amine had been added,heatin~ of the reaction mixture was continued at 130C for another 2 hours. The reaction product had a melting point of 84-91C and an 11.1% content of blocked NCO.
Example 5 2S2 parts by weight o~ 2,2,4,6-tetramethylpiperidine were added drop-by-drop over a period of approximately 2 hours to 222 parts by weight of IPDI at 130 C. After the 2,2,4,6-tetramethylpiperidine had been added, heating of thQ reaction mixture at 130C was continued for approximately 1 hour.
The reaction product had a melting point of 120-125C
and a 16.6% content of b~ocked NCO. In contrast to the compounds in Examples 1-4, the amine used for blocking was quantitat.ively detected within about 2 hours, by titration with aqueous ~Cl.
Thus the IPDI hlocked with 2,2,4,6-tetramethylpiperidine is not hydrolysis resistant.
Example 6 202 parts by weight of diisopropylamine were added drop-by-drop within 2 hours to 168 parts by weight of hexamethyl-ene diisocyanate at 130C. After all the diisopropylamine hadbeen added, heating of the reaction mixture at 130C was continued for about 1 hour~ The reaction product had a melting point o~ 130-140C and a 22.7% content of blocked NCO.
Example _ 41.~ parts by weight of diisopropylamine were added at 100C over about 3 hours to 100 parts ~y weight of IPDI-T
1890 (trimer IPDI; product of the Chemische Werke Huels~ with a 17.2% NCO content that had been dissolved in 100 parts by weight of xylol/ethyl glycol acetate (weight ratio: 2:1). Thereafter, heating was continued for 2 hours. The solution thus obtained had a viscosi~y of 261 mPas at room temperature. The content of blocked NCO was 7.1%.
II. Reactivity of the Compounds To examine the reactivity of a polyisocyanate, blocked with an amine, with a polyol, the polyisocyanate was kneaded in a kneading chamber with a polyol at a ratio of (NCOblock:OH = 1:1) at various temperatures and the resistance to kneading was followed as a function of time. The resistance to kneading increased to the same extent as the reaction occurred. When cross-linking occurred, the resistance to kneading rose sharply followed by an abrupt drop. The cross-linked product was finely ground and then offered only slight resistance. The polyiso-cyanate used was a diisocyanate. The results are shown in Table 1.
.
~8~7~3 Table J
Hardeners _neading Behaviour of Hardenrs/Oxyester P 1137 (NCO : OH = 1 : 1) at 120 C 160 C 1~0 C
IPDI blocked with piperidine - no cross- -linking IPDI blocked with 2,6 dimethylpiperidine cross-linked cross-linked after 10 after 4 minutes minutes IPDI blocked with 2,2,4,6-tetramethyl-piperidine immediately cross-linked IPDI blocked with caprolactam cross-linked after 18 minutes P 1137: Oxyester with an OH number of 106-114 and a melting range of from 70-90C (product of the Chemische Werke Huels) III. Appllcation Examples Application Example 1 A) Polyester containing hydroxyl groups (production) 7 moles of isophthalic acid (1.163 g~/ 6 moles of hexanediol-1,6 (709 g) and 2 moles of l,l,l-trimethylolpropane (268 g) were esterified in a 4-liter glass flask with the admixture of 0.1% by weight of n-dibutyltin oxide. With rising temperature, a homogenous batch developed. At about 195C, the first separation of water occurred. Within 8 hours, -the tempera-ture was raised to 220C and at this temperature the ester;fication was completed during the subsequent 6 hours. The :~8'7~83 acid number was smaller than 1 mg KOH/g. After the polyester batch had been cooled down to 200C, the volatile components were removed in a vacuum of 20-30 mm Hg during 30-45 minutes.
During the entire reaction, a weak N2-flow was directed through the xeaction systemO
Chemical and physical characteristics data of the polyester:
OH number 105 mg KOH/g Acid number <1 mg KOH/g Mole weight 2400 Glass transition temperature -12C to +5C
B) Blocked isocyanate components The polyisocyanate described in production Example 3 was used.
C) PUR heat-curing coating -100 g of the polyester obtained in part A of this application example are mixed and dissolved with 398 g of the blocked polyisocyanate of production Example 3, in 466 g n-butylacetate and 446 g xylol solvents at 40-50C to form a resin solution. In the customary fashion, a heat-hardening white coating was formulated according to the following composi-tion 65% by weight of the above-described resin solution;
3% by weight of n-butyl glycol acetate;
2% by weight of iosphorone;
2808% by weight of a white pigment (Tio2);
2% by weight of a 10% solution of a soluble flow ~87~83 improver in ethylglycol acetate; on the basis of an organo-functional silicone oil, and 0.2% by weight dibutyltin dilaurate.
An aluminum sheet was coated with the described coating and hardening was undertaken under varying conditions.
The test results are presented in Table 2.
Table 2 .
E~ardening Condition Coating Testing .
_ PE~ ET GS G20 G45 G60 MEK Test Yellowing min 110C 40 153 0.5 1 90 60 96 60 none min 120C 30 179 7.8 0 87 56 96 >200 none min 1400C 35 181 6.5 0 90 55 94 >200 none 0.75 min 300 C 25 174 8.5 0 69 56 92 >200 none Explanation of symbols:
SD: coating thickness in llm PH: Koenig pendulum hardness, DIN 53 157 ET: Erichsen cupping, DIN 53 156 GS: Cross-cut adhesion test, DIN 53 151 G: gloss according to Gardner ASTMD 523 The test data shown in Table 2 illustrate that quantitative cross-linking/hardening is possible with the above-described coating material starting from about 120C.
Surprisingly, no yellowing occurs d~spite the aminic blocking agent.
1~8~
Application Example 2 A) Polyester containing hydroxyl groups (production) Analogously to the process described in application Example lA, a polyester containing hydroxyl groups was produced.
The following raw materials were used:
moles isophthalic acid (1661 g) 5~5 moles hexanediol-1,6 (650 g) 2.0 moles diethylene glycol (212 g)
4.0 moles trimethylolpropane (537 g) Characteristic values of the polyester:
OH number 132 mg KOH/g Acid number 2 mg KOH/g The polyester was dissolved in n-butylacetate/xylol solvent (1:1).
The solid substance content of the solution was 60% by weight.
B) Blocked isocyanate components -The blocked polyisocyanate described in production Example 7 was used.
G) PUR heat-curing coating A clear coating was formulated according to the following composition:
49.3~ solution of the polyester obtained in part A
of this application example;
41.5~ solution of the blocked polyisocyanate produced in production example 7;
3.0% butylglycol acetate;
2.0~ isophorone;
~17~1~3 1.0~ of a 10~ solution of a flo~ improver in ethylglycol acetate on the basis of an organofunctional silicone oil;
0.2~ dibutyl tin dilaurate.
An aluminum sheet was coated with the above-described coating material and was hardened under various conditions.
The test results are shown in Table 3.
Table 3 Hardening 10Condition COATING TESTING
SD P~I ET GS MEK-Test Yellowing 25 min 1300C 35 186 7.0 0 >200 none 7 min 160 C 40 193 7.8 0 >200 none 4 min 180C 40 186 8.1 0 >200 none ~ . .
Explanation of symbols:
SD: coating thickness in ~m PH: Koen.Lg pendulum hardness, DIN 53 157 ET: Erichsen cupping, DIN 53 156 GS Cross-cut adhesion test, DIN 53 151 G: gloss according to Gardner ASTMD 523 The test data shown in Table 3 illustrates that cross-linking/hardening of the above-described coating yields results at a temperature of 130C which are comparable to those ob-tained at a temperature of 180C.
8~33 Having now fully described this invention, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention as set forth herein.
OH number 132 mg KOH/g Acid number 2 mg KOH/g The polyester was dissolved in n-butylacetate/xylol solvent (1:1).
The solid substance content of the solution was 60% by weight.
B) Blocked isocyanate components -The blocked polyisocyanate described in production Example 7 was used.
G) PUR heat-curing coating A clear coating was formulated according to the following composition:
49.3~ solution of the polyester obtained in part A
of this application example;
41.5~ solution of the blocked polyisocyanate produced in production example 7;
3.0% butylglycol acetate;
2.0~ isophorone;
~17~1~3 1.0~ of a 10~ solution of a flo~ improver in ethylglycol acetate on the basis of an organofunctional silicone oil;
0.2~ dibutyl tin dilaurate.
An aluminum sheet was coated with the above-described coating material and was hardened under various conditions.
The test results are shown in Table 3.
Table 3 Hardening 10Condition COATING TESTING
SD P~I ET GS MEK-Test Yellowing 25 min 1300C 35 186 7.0 0 >200 none 7 min 160 C 40 193 7.8 0 >200 none 4 min 180C 40 186 8.1 0 >200 none ~ . .
Explanation of symbols:
SD: coating thickness in ~m PH: Koen.Lg pendulum hardness, DIN 53 157 ET: Erichsen cupping, DIN 53 156 GS Cross-cut adhesion test, DIN 53 151 G: gloss according to Gardner ASTMD 523 The test data shown in Table 3 illustrates that cross-linking/hardening of the above-described coating yields results at a temperature of 130C which are comparable to those ob-tained at a temperature of 180C.
8~33 Having now fully described this invention, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention as set forth herein.
Claims (15)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A polyurethane heat-curing coating material which is stable in storage and is hardened above a temperature of about 120°C, which comprises a polyol compound having a low glass transition temperature, and a blocked polyisocyanate compound, wherein said blocked polyisocyanate compound is the reaction product of a polyisocyanate compound and a secondary amine com-pound having the formula:
wherein R is selected from the group consisting of hydrogen atom, C3-C9 alkyl radical, unsubstituted cycloalkyl radical, cyclo-alkyl radical, cycloalkyl radical substituted by C1-C4 alkyl radicals, heteroatom-containing cycloalkyl radical, unsubstituted aralkyl radical, aralkyl radical substituted by C1-C4 alkyl radicals, or heteroatom-containing aralkyl radical, wherein each R
is identical to or different from each other; R1 is selected from the group consisting of alkyl radical, cycloalkyl radical, or aralkyl radical, wherein each R1 is identical to or different from each other; or R and R1 are chemically bonded therebetween, thereby forming a ring structure.
wherein R is selected from the group consisting of hydrogen atom, C3-C9 alkyl radical, unsubstituted cycloalkyl radical, cyclo-alkyl radical, cycloalkyl radical substituted by C1-C4 alkyl radicals, heteroatom-containing cycloalkyl radical, unsubstituted aralkyl radical, aralkyl radical substituted by C1-C4 alkyl radicals, or heteroatom-containing aralkyl radical, wherein each R
is identical to or different from each other; R1 is selected from the group consisting of alkyl radical, cycloalkyl radical, or aralkyl radical, wherein each R1 is identical to or different from each other; or R and R1 are chemically bonded therebetween, thereby forming a ring structure.
2. A polyurethane one-component heat-curing coating material according to claim 1, wherein said polyisocyanate compound is a monomeric, dimeric or trimeric polyisocyanate compound.
3. A polyurethane one-component heat-curing coating material according to claim 1, wherein said polyisocyanate compound is a chain-extending polyisocyanate compound.
4. A polyurethane one-component heat-curing coating material according to claim 2, wherein said monomeric polyisocyanate is selected from the group consisting of aliphatic, cycloaliphatic, araliphatic, aryl-substituted aliphatic and aromatic diisocyanates and aromatic triisocyanates.
5. A polyurethane one-component heat-curing coating material according to claim 4, wherein said monomeric polyisocyanate is 3-isocyanato-methyl-3,5,5-trimethylcyclohexylisocyanate.
6. A polyurethane one-component heat-curing coating material according to claim 4, wherein said monomeric polyisocyanate is toluene diisocyanate and isomer mixtures thereof.
7. A polyurethane one-component heat-curing coating material according to claim 1, 2 or 3, wherein said secondary amine com-pound is selected from the group consisting of diisopropylamine, isopropyl-tert-butylamine, dicyclohexylamine, di-(3,5,5-trimethylcyclohexyl)amine, 2,6-dimethylpiperidine, 2,5-dimethylpyrrolidine, 2,2,6,6-tetramethylpiperidine, 2,2,4,6-tetramethylpiperidine, and isopropylcyclohexylamine or a mixture thereof.
8. A polyurethane one-component heat-curing coating material according to claim 1, wherein said polyol compound is selected from the group of polyesters, polyethers, polyacetals, polyesteramides, and polyepoxides.
9. A polyurethane one-component heat-curing coating material according to claim 8, wherein said polyol has 2 to 6 hydroxyl groups and a molecular weight of about 400 to 2000.
10. A polyurethane one-component heat-curing coating material according to claim 1, 2 or 3, wherein the reaction product of said polyisocyanate compound and said secondary amine comprises a compound having a molecular weight in the range of 300 to 2500 with a melting temperature in the range of 30° to 220°C.
11. A method for producing a polyurethane one-component heat-curing coating material according to claim 1 which comprises mixing a polyester compound, a blocked polyisocyanate compound and a high-boiling inert organic solvent in a reaction vessel at 80° to 100°C.
12. A method according to claim 11, wherein said blocked polyisocyanate compound is prepared by mixing said polyisocyanate compound with a high-boiling inert organic solvent, heating the mixture of said polyisocyanate compound and said organic solvent to a temperature of about 70° to 120°C, adding said secondary amine compound to the heated mixture such that the temperature of the reaction mixture does not exceed about 130°C, and heating said reaction mixture at about 100° to 120°C for a period of about an hour.
13. A method according to claim 11, wherein the total con-centration of said polyester compound and said blocked polyiso-cyanate compound in the high-boiling inert organic solvent is about 40 to 70% by weight.
14. A method of coating a high quality object made of metal, glass, or plastic which comprises applying a polyurethane one-component heat-curing coating material according to claim 1 to a surface of said object, and heating said object coated with said coating material to a temperature in the range of 120° to 350°C
for a period of about 30 minutes to 30 seconds, thereby hardening said coating material to form a coating on the surface of said object.
for a period of about 30 minutes to 30 seconds, thereby hardening said coating material to form a coating on the surface of said object.
15. A blocked polyisocyanate compound which is the reaction product of a polyisocyanate compound and a secondary amine compound having the formula:
wherein R is selected from the group consisting of hydrogen atom, C3-C9 alkyl radical, unsubstituted cycloalkyl radical, cycloalkyl radical substituted by C1-C4 alkyl radicals, heteroatom-containing cycloalkyl radical, unsubstituted aralkyl radical, aralkyl radical substituted by C1-C4 alkyl radicals, or heteroatom-containing aralkyl radical, wherein each R is identical to or different from each other; R1 is selected from the group consisting of alkyl radical, cycloalkyl radical, or aralkyl radical, wherein each is identical to or different from each other; or R and R1 are chemically bonded therebetween, thereby forming a ring structure.
wherein R is selected from the group consisting of hydrogen atom, C3-C9 alkyl radical, unsubstituted cycloalkyl radical, cycloalkyl radical substituted by C1-C4 alkyl radicals, heteroatom-containing cycloalkyl radical, unsubstituted aralkyl radical, aralkyl radical substituted by C1-C4 alkyl radicals, or heteroatom-containing aralkyl radical, wherein each R is identical to or different from each other; R1 is selected from the group consisting of alkyl radical, cycloalkyl radical, or aralkyl radical, wherein each is identical to or different from each other; or R and R1 are chemically bonded therebetween, thereby forming a ring structure.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3221558.4 | 1982-06-08 | ||
| DE19823221558 DE3221558A1 (en) | 1982-06-08 | 1982-06-08 | STORAGE POLYURETHANE COMPONENT BURNING VARNISHES |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1187083A true CA1187083A (en) | 1985-05-14 |
Family
ID=6165601
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000429843A Expired CA1187083A (en) | 1982-06-08 | 1983-06-07 | Blocked polyisocyanate compounds and polyurethane heat-curing coatings containing said compounds |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0096210B1 (en) |
| JP (1) | JPS594658A (en) |
| CA (1) | CA1187083A (en) |
| DE (2) | DE3221558A1 (en) |
| ZA (1) | ZA834167B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6784243B2 (en) | 2002-06-17 | 2004-08-31 | Bayer Aktiengesellschaft | Polyurethane-polyurea dispersions |
| US7074852B2 (en) | 2003-06-27 | 2006-07-11 | Bayer Materialscience Ag | Blocked polyisocyanates |
| US7087676B2 (en) | 2003-06-27 | 2006-08-08 | Bayer Materialscience Ag | Blocked polyisocyanates |
| US10604673B2 (en) | 2015-09-11 | 2020-03-31 | Asahi Kasei Kabushiki Kaisha | Blocked polyisocyanate composition, one-component coating composition, coating film, and coated article |
Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3311516A1 (en) * | 1983-03-30 | 1984-10-04 | Basf Farben + Fasern Ag, 2000 Hamburg | HEAT-CURABLE COATING AGENTS AND THEIR USE |
| DE3434881A1 (en) * | 1984-09-22 | 1986-04-03 | Hüls AG, 4370 Marl | STORAGE POLYURETHANE POWDER VARNISH |
| GB8623971D0 (en) * | 1986-10-06 | 1986-11-12 | Ici Plc | Urea-modified isocyanates |
| DE3724555A1 (en) * | 1987-07-24 | 1989-02-02 | Basf Ag | VISCOSITY-REGULATING SUBSTANCES FOR SINGLE-COMPONENT POLYURETHANE SYSTEMS |
| DE3922767A1 (en) * | 1989-07-11 | 1991-01-17 | Bayer Ag | HEAT-CREAMABLE MIXTURES AND THEIR USE FOR THE PRODUCTION OF COATINGS ON HEAT-RESISTANT SUBSTRATES |
| DE4028288A1 (en) * | 1990-09-06 | 1992-03-12 | Huels Chemische Werke Ag | COLD-HARDENING, SOLVENT-FREE, DUROPLASTIC POLYURETHANE-POLYHANE MATERIALS |
| DE4028284A1 (en) * | 1990-09-06 | 1992-03-12 | Huels Chemische Werke Ag | LIGHT-RESISTANT, REACTIVE 2-C PUR LACQUERS THAT HARD AT ROOM TEMPERATURE |
| DE4028285A1 (en) * | 1990-09-06 | 1992-03-12 | Huels Chemische Werke Ag | BLOCKED (CYCLO) -ALIPHATIC POLYISOCYANATES AND A METHOD FOR THE PRODUCTION THEREOF |
| DE4240480A1 (en) * | 1992-12-02 | 1994-08-25 | Bayer Ag | Organic polyisocyanates with at least partially blocked isocyanate groups |
| DE19631993A1 (en) * | 1996-08-08 | 1998-02-12 | Huels Chemische Werke Ag | New moisture-curing PUR hot melt adhesives |
| DE10134238A1 (en) * | 2001-07-13 | 2003-01-23 | Bayer Ag | An aqueous and/or water dilutible blocked polyisocyanate crosslinking agent, useful for preparation of stoving enamels and automobile finishing, comprises polyisocyante, diisopropylamine, hydrophilizing agent and chain lengthening agent |
| DE10226931A1 (en) * | 2002-06-17 | 2003-12-24 | Bayer Ag | Polyurethane-polyurea dispersions |
| DE10226927A1 (en) * | 2002-06-17 | 2003-12-24 | Bayer Ag | Blocked polyisocyanates |
| DE10226925A1 (en) * | 2002-06-17 | 2003-12-24 | Bayer Ag | Blocked polyisocyanates |
| BR112012019717A2 (en) | 2010-02-08 | 2023-11-21 | Asahi Kasei Chemicals Corp | BLOCKED POLYISOCYANATE COMPOSITION, COATING COMPOSITION, COATING FILM, AND, METHOD FOR PRODUCING A BLOCKED POLYISOCYANATE COMPOSITION |
| WO2017169559A1 (en) | 2016-03-29 | 2017-10-05 | 旭化成株式会社 | Block polyisocyanate composition, one-part coating composition, coating film, and coated article |
| EP3643733A1 (en) | 2018-10-24 | 2020-04-29 | Basf Se | Blocking agents for isocyanates |
| EP4282893A1 (en) | 2022-05-25 | 2023-11-29 | Covestro Deutschland AG | Blocked polyisocyanates |
| EP4282894A1 (en) | 2022-05-25 | 2023-11-29 | Covestro Deutschland AG | Single-component stoving system |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3947426A (en) * | 1974-04-12 | 1976-03-30 | Story Chemical Corporation | Solid particle-form polymerizable polymeric material and compositions, structures and methods of employing and producing the same |
| DE2744782A1 (en) * | 1977-10-05 | 1979-04-12 | Veba Chemie Ag | STORAGE-STABLE STOVE ENAMELS |
| GB2066275B (en) * | 1979-12-21 | 1983-06-02 | Takeda Chemical Industries Ltd | Precoated metal and its production |
| JPS58160311A (en) * | 1982-03-18 | 1983-09-22 | Asahi Chem Ind Co Ltd | New resin composition, paint therefrom, crosslinked product thereof and paint film formation therewith |
-
1982
- 1982-06-08 DE DE19823221558 patent/DE3221558A1/en not_active Withdrawn
-
1983
- 1983-04-28 DE DE8383104156T patent/DE3362063D1/en not_active Expired
- 1983-04-28 EP EP83104156A patent/EP0096210B1/en not_active Expired
- 1983-06-07 CA CA000429843A patent/CA1187083A/en not_active Expired
- 1983-06-07 JP JP58100372A patent/JPS594658A/en active Granted
- 1983-06-08 ZA ZA834167A patent/ZA834167B/en unknown
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6784243B2 (en) | 2002-06-17 | 2004-08-31 | Bayer Aktiengesellschaft | Polyurethane-polyurea dispersions |
| US7074852B2 (en) | 2003-06-27 | 2006-07-11 | Bayer Materialscience Ag | Blocked polyisocyanates |
| US7087676B2 (en) | 2003-06-27 | 2006-08-08 | Bayer Materialscience Ag | Blocked polyisocyanates |
| US10604673B2 (en) | 2015-09-11 | 2020-03-31 | Asahi Kasei Kabushiki Kaisha | Blocked polyisocyanate composition, one-component coating composition, coating film, and coated article |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS594658A (en) | 1984-01-11 |
| EP0096210B1 (en) | 1986-02-05 |
| DE3221558A1 (en) | 1983-12-08 |
| ZA834167B (en) | 1984-03-28 |
| DE3362063D1 (en) | 1986-03-20 |
| JPH039948B2 (en) | 1991-02-12 |
| EP0096210A1 (en) | 1983-12-21 |
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