CA1327664C - Epoxy resin powder coating composition - Google Patents
Epoxy resin powder coating compositionInfo
- Publication number
- CA1327664C CA1327664C CA000577239A CA577239A CA1327664C CA 1327664 C CA1327664 C CA 1327664C CA 000577239 A CA000577239 A CA 000577239A CA 577239 A CA577239 A CA 577239A CA 1327664 C CA1327664 C CA 1327664C
- Authority
- CA
- Canada
- Prior art keywords
- epoxy resin
- coating composition
- powder coating
- resin powder
- weight
- 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 - Fee Related
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D163/00—Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
-
- 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
- C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
- C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
- C08G59/20—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the epoxy compounds used
- C08G59/22—Di-epoxy compounds
- C08G59/226—Mixtures of di-epoxy compounds
-
- 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
- C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
- C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
- C08G59/20—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the epoxy compounds used
- C08G59/32—Epoxy compounds containing three or more epoxy groups
- C08G59/38—Epoxy compounds containing three or more epoxy groups together with di-epoxy compounds
-
- 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
- C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
- C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
- C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
- C08G59/50—Amines
- C08G59/5046—Amines heterocyclic
- C08G59/5053—Amines heterocyclic containing only nitrogen as a heteroatom
- C08G59/5073—Amines heterocyclic containing only nitrogen as a heteroatom having two nitrogen atoms in the ring
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L21/00—Compositions of unspecified rubbers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
Abstract
ABSTRACT OF THE DISCLOSURE
An epoxy resin powder coating composition which comprises:
(A) an epoxy resin comprising mainly of a bisphenol A type epoxy resin mixture of (a) a bisphenol A
type epoxy resin having a number average molecular weight of from 2,500 to 8,000 and (b) a bisphenol A type epoxy resin having a number average molecular weight of from 350 to 1,700, said mixture having a number average molecular weight of from 1,700 to 4,500;
(B) rubber powder in an amount of 2 to 30 parts by weight per 100 parts by weight of said epoxy resin (A);
(C) at least one hardener; and (D) a filler.
The coating composition is particularly useful for the insulation of slots for motor rotors, exhibiting excellent thermal resistance, adhesiveness, impact resistance and coverage.
An epoxy resin powder coating composition which comprises:
(A) an epoxy resin comprising mainly of a bisphenol A type epoxy resin mixture of (a) a bisphenol A
type epoxy resin having a number average molecular weight of from 2,500 to 8,000 and (b) a bisphenol A type epoxy resin having a number average molecular weight of from 350 to 1,700, said mixture having a number average molecular weight of from 1,700 to 4,500;
(B) rubber powder in an amount of 2 to 30 parts by weight per 100 parts by weight of said epoxy resin (A);
(C) at least one hardener; and (D) a filler.
The coating composition is particularly useful for the insulation of slots for motor rotors, exhibiting excellent thermal resistance, adhesiveness, impact resistance and coverage.
Description
13276~
FIELD OF THE INVENTION
The present invention relates to an epoxy resin powder coating composition suitably used for the insulation of slots of motor rotors.
BACKGROUND OF THE INVENTION
~ poxy resin powder coating compositions are widely used for the insulation of electric and electronic equipments and parts. Examples are in JP-A-55-84371 and ~ 10 57-42760 (the term "JP-A" as used herein means an unexamined published Japanese patent application) which disclose powder coating compositions comprising a rubber modified epoxy resin, a hardener, and a filler. Those powder coating compositions are effective to form insulating films on smooth surfaces, however, are not satisfactory as insulating powder coating compositions for slots having edges such as in motor rotors and stators of ele~tric and electronic equipments and parts.
A temperature of 180C or higher is required to rapidly harden the epoxy resin to form insulating films on slots having edges. However, the aforesaid conventional epoxy resins, when heated under such a temperature condition, fail to form films with sufficient thickness on the edge parts, and, moreover, lack the necessary physical : '.
':
~ , 1327g~4 1 properties such as thermal resistance, adhesiv~ness, and impact resistance. In addition, surface smoothness is not attained.
SUMMARY OF THE INVENTION
The present invention aims to provide an epoxy resin powder coating composition which overcomes the aforesaid shortcomings of the conventional epoxy resin - powder coating compositions.
That is, the present invention provides an epoxy resin powder coating composition which comprises:
(A~ an epoxy resin comprising mainly of a bisphenol A type epoxy resin mixture of (a) a bi~phenol A type ,epoxy resin having a number average molecular weight of from 2, 500 to 8, 000 and ~b) a bisp~enol A type epoxy resin ~ 15 ~aving 8 number average molecular weight of from 350 eo 1 1,700, said ~ixeure baving a number average molecular weight of from 1~700 to 4,500;
(B~ rubber powder ~n an amount of 2 to 30 part~ -by weight per lOO parts by weiqht of said epoxy resin (A); ~' (C) at least one hardener; and (D) a filler. ' , , DETAILED EXPL~NATION OF THE INVENTION '~
The epoxy resin used in the present invention is j based on bisphenol A type epoxy resin. The bisphenol A ,~
1 25 type epoxy resin is pr.epared by blending a bisphenol A
! q~ epoxy ~#~n having a nu~ average leQ~ar weight of from 2,500 ~,','''',', .. ~ ....
, ~ ~' , .
1327~4 to 8,000 with that having a nu~r average m~lecular weight of from 350 to 1,700.
` The mixture has a n~r average molecular weight of from 1,700 to 4,500, preferably from 1,800 to 4,000, and more preferably from 2,000 to 3,000- When the n~r average molecular weight is less than 1,700, the edge coverage ' decreases, and when it exceeds 4,500, it is not appropriate since adhesiveness or surface smoothness of film is damaged and is apt to form pinholes.
` 10The bisphenol A type epoxy resin is a synthetic resin obtained by condensation polymerization of bisphenol A and epichlorohydrin, and is represented by general formula ~
. ..-15 ` O - C~13 ~ o~ C~3 0 CH2-CB-C~2 o~ CH2-1B-CB2 ~ ~ -CH2-CH-C~2 CH~ CB3 n wherein n is a degree of polymerization.
ffle bispx~ol A type ep~y resin a having a number average molecular weight of from 2,500 to 8,000 suitably used in the present invention has a melting point of from 120 to 160C, and pr~ably ~rom 130 to 150C. ffle nu~r average mol~ar weight of (a) is preferably from 2,700 to 6,S00.
. `D ~ ~
1327~4 The other bisperx)l A type epoxy resin b ~ving a nuT~er average molecular weight of from 350 to 1,700 has a melting point - of 100C or lower, preferably having a liquid phase at '3 ordinary temperature. The molecular weight of (b) is preferably from 30Q to 50Q.
A mixture of (a! and (b) is used for the present invention.
Also, a third different bisphenol A type epoxy resin with a nu~x~ average mole~i~r weight of ~mm 1,700 to 2,500 may be added in a small amount (generally, of from 5 to 40~ by weight, preferably from 5 to 35% by weight, and more preferably from 10 to 3Q~ by weight of the total amount of the epoxy resins) such that the nu~r average mole~ar weight ~ of the resulting mixture is in the range of from 1,700 to ¦ 15 4,500. Further, an epoxy resin of a different type may be ~ added in ~n amount of, generally from 5 to 40~ by weight, i preflerably from 5 to 35~ by weight, and more preferably from 10 to 30~ by weight of the totàl amount of the epoxy ~ resins.
¦ 20 Example of epoxy resins other than bisphenol A
type include polyfunctional epoxy resins having three or I more epoxy groups in the molecule. Such epo~y resinsinclude novolak type (o-cresol novolak type, phenol novolak type, etc.) e]poxy resins, triglicydyl ether epoxy type reslns ~epoxy co~npounds of cyanuric acid or . ',;.
-- 4 ~
`` 13~7~
1 triphenylpropane) and tetraglycidyl ether type epoxy resins (epoxy compounds of bisresorcinol F or tetraoxy tetraphenylethane, etc.).
, When the polyfunctional epoxy resin is used in the j 5 coating composition of the present invention, the proportion of the polyfunctional epoxy resin is generally from 5 to 40~ by wei~ht, preferably from 5 to 35% by w~ight, and more preferably from 10 to 30% by wei~ht of the total amount of the epoxy resins.
Other types of epoxy resins may be used in the present invention, provided that the epoxy resin other ~ than bisphenol A type should not be incorporated in an ¦ amount of more than 40% by weight of the total epoxy resin~ -3 15 In the powder coating composition of the present invention, rubber powder is blended. The content of the rubber powder in the coating composition is from 2 to 30 parts, preferably from 5 to 15 parts by weight per 100 parts by weight of the total amount of epoxy resin. This ¦ 20 relative content provides for a powder coating composition having a coating property especially improved in edge coverage and thermal resistance.
The rubber powder used in the present invention is essentially chemically inert to epoxy resin. Further, it .
:.
_ 5 _ - . "
1327~4 1 substantially disperses in the solid state when mixed with ; molten epoxy resin.
Examples of rubber powders are nitrile/butadiene t, based rubber (NBR), a chloroprene rubber, butadiene rubber, isoprene rubber, etc. The particle size of the rubber should be in the range of from about 100 to 500 ~m, ~ preferably from 130 to 250 ~m.
~~ When it is mixed with molten epoxy resin, it is preferable to use the rubber powder in a mixture with a filler, especially with calcium carbonate. The rubber powder is better dispersed in molten epoxy resin when used `
as a mixture. Moreover, rubber powder is more readily ~ ground to fine powder and the filler incorporated in the `2~ mixture avoids blocking of the finely ground rubber .,.
po~der.
The amount of filler added is preferably from 5 to `
25 parts, and more pre$erably from 10 to 20 parts, by weight, per 100 parts by weight of rùbber powder. `
The hardener to be blended with the powder coating composition of the present invention includes those conventiona~ly usedr such as aromatic amines, acid anhydrides, guanidines (dicyandiamide, etc.), and imidazoles. To achieve optimal gloss, adhesiveness and I edge coverage, two or more hardeners having different hardening speed can be appropriately blended to give a - ;
',,`.
.,.
i - 6 -?~ . .
,' ' ' .
1 mixture of hardeners with controlled hardening speed. Too high a hardening speed results in a hardener which gives a dull coatin~ with poor adhesiveness, and too low a speed results in poor edge coverage. The amount of hardener added differs according to the type. An example is an s imidazole type hardener which is added in an amount of from O.l to 5 parts, preferably from 0.2 to 4 parts by weight per lO0 parts by weight of the total amount of the epoxy resins.
~ lO In the case of using a combination of hardeners havinq different hardening speed, the high speed hardener can function as a hardening promoter to the low speed hardener.
Specific examples of the low speed hardeners include 2-methyl imidazole, diaminodiphenylsulfone, ¦ diaminodiphenylether, etc.
Specfic examples of the high speed hardeners include 2,4-diamino-6-12'-methylimidazolyl (l)]ethyl-s-triazine, 2-phenyl imida20le, 2-ethyl-4-methyl imidazole, etc~
When a mixture of two or more hardeners having different hardening speed is employed, the combination of ¦ an imidazole type high speed hardener with a low speed ! hardener chosen from ~elow is preferred.
1327~4 1 Examples of imidazole compounds that are high speed hardeners can be expressed in accordance with general formula (II);
Rl-N ~ (II) R
, wherein Rl represents a hydro~en atom or an alkyl group - -substituted with an aryl group (e.g., -CH2- ~ ), and R2 represents a substituted or unsubstituted alkyl group (e.g., CH3, C~Hs, CH(CH3)2, CllH23, C~H35) or an aryl group te.g... phenyl, tolyl, xylyl). Preferably, the alkyl `
group has 1 to 20 carbon atoms and the aryl group has 6 to 20 carbon atoms.
Examples of imidazole compounds that are low speed hardeners can be expressed in accordance with general ~ormula (III);
~ ,'~'.
!
. . .
.
A
.~ ......
1327~4 R3-N ~ (III) 1 wherein R3 represents an alkyl group substituted with a cyano group (e.g., C~2C~2CN) or a group of CH2CH2 ~ ~ , and R~ represents a substituted or unsubstituted alkyl group (e.g., CH3, C2~5, CH(CH3)2, ~23- Cl7~3s) or an aryl group (e.g~, phenyl, tolyl, ..
xylyl3. Preferably, thle alkyl group has 1 to 20 carbon atoms and the aryl group has 6 to 20 carbon atoms.
In the case of using a combination of imidazole type hardeners, preferably O.OS to 0.7 part by weight of a high speed hardener is used with 0.5 to 3 parts by weight of a low speed hardener per 100 parts by weight of the total amount of epoxy resins.
lS Inorganic }illers suitably blended with the composition of the present invention include silica, calcium carbonate, alumina, clay, mica, talc, and powdered glass fibers. ~he amount to be blended is generally from 5~ ' ''f ' ,`' _ 9 - ' ' .
~3276~4 :`
1 10 to 80%, and preferably from 20 to 50~, by weight, of the total weight of the powder coating composition.
Conventional additives such as leveling agents (e.g., acrylic acid ester oligomers), pigments (e.g., Cr203, Fe203), impact resistance improvers (e.g., butadiene-acrylonitrile copolymer, butyral resin), and hardening promoters (e.g~, 2-phenylimidazole, 2-ethyl-4-methylimidazole) may be appropriately blended with the powder coating composition of the present invention.
Conventional methods can be used to blend the components of the epoxy resin powder coating composition of the present invention. For example, the components can be dry-mixed with a mixer or the like, melt-mixed using a kneader or the like, or solidified by cooling after melt-mixed usinq an extruder or the like, and then ground to :
fine particles.
The present invention is hereinafter described in qreater detail with reference to the examples, which are not to be construed as limiting the scope thereof. Unless otherwise indicated, all parts, percents and ratios are by weight.
Epoxy resin powder coating compositions as shown in Table 1 were prepared. The following are the explanations for ~he c:omponents in Table 1.
: :
.
, ~ :
~ .
13276~
Epikote 1007*: a bisp~enol-A type epoxy resin having a n ~ er average molecular wei~ht of about 2,900, with a melting point of 128C; from Yuka Shell Epoxy Co. Ltd.
EOCN 104*: an o-cresol novolak type epoxy resin having a softening point of 95C; from Nippon Kayaku Co~ Ltd.
Epikote lQ04*: a bisp~enol-A type epo~cy resin having a n ~ er average molecular weight of about 1,600, with a ~ 10 melting point of 98C; from Yuka Shell ,~ Epoxy Co. Ltd.
Rubber modified epoxy resin: ~ -an epoxy resin modified with a liquid nitrile rubber having a -COOH group at the end, with a melting point of 100C; ~ -Epomic SR-35K from Mitsui Petro-~ chemicals Industries , Ltd.
`~ Rubbçr Powder: a mixture containing 87% by weight of rubber having a Mooney viscosity of 75 to 85 and 13% by weight of calcium carbonate; the calcium carbonate powder is substantially adhered on the surface of the rubber particles. ~he particle distribution is as follows:
, 25 0~5% of over 35 ~m mesh, 2.5% of over j *Trade Mark ` :.
`1 `
D ;:
1 3 2 7 ~ 6 4i .` 1 42 ~m mesh, 22% of over 60 ~ mesh, 43%
~x of over 80 ~m mesh, 18.5~i of over 125 -~ ~m mesh, and 13.5% of under 125 ~m ~? mesh. HI-BLOW HF-21~ from Nippon Zeon Co., Ltd.
Hycar-CTsN*: a butadiene-acrylonitrile copolymer with carboxyl groups at both ends, having a viscosity of l,200 poises at 27C; from ~he B.F. Goodrich Chemical -Corp.
Leveling agent: an acrylic ester oligomer Hardener A: 2-methylimidazole Hardener B: 2~4-diamino-6-[2'-methylimidazolyl (l,?3ethyl-s-triazine lS DAM: 4,4'-diaminodiphenylmethane AD~: Adipic acid dihydrazide `
Then, each of the aforesaid samples were coated on slots of motor rotors at 180 to 260C usin~ a flow-imm~rsion method, and the properties ~of each of the obtained films were investigated using the methods as follows. Thè results are given in Table 2.
(l) Edge coverage :.:
A half-inch square bar was coated with the powder coating composition at a thickness of about 0.3 mm and subjected to ASTM D-2916~ standardized measurements. Those *Trade Mark ? 12 -B
~.
1327~6~
1 having hisher ratio (%) are evaluated as having excellent edge coverage.
~2) Thermal resistance A metal mold having a concave of 12.7 mm width, 170 mm length, and 12.7 mm depth was first heated to 160 !~ to 170C, then, the powder coating composition was applied } to the heated metal mold for 10 to 15 minutes, then molded, and thermoset at 170C for 20 minutes. The heat deformation temperature (~DT) of the hardened body was ;~ 10 obtained according to the ~STM D-648 standard. Those having higher HDTs have higher thermal resistances.
~t ( 3) Adhesiveness Two degreased test pieces ~soft steel plates of 100 mmx20 mmx3 mm) were heated to about 200C. The powder coating co~position was adhered in molten state on the upper surface (20 mm wide and about 15 mm long) of the tip of the either test piece, and was applied to the tip ~20 mm wide and 10 mm long) of the other test piece under load of 1 kg at 200C for 10 minutes to harden by heating.
Then, the test pieces were left at room temperature and the tensile` stren~th at which the joint broke was measured. Those having larger strenqth are evaluated as having excellent adhesiveness.
-t . :
1327~
1 ~4) Impact resistance Preparation of the coated test piece:
~ A soft steel plate of 60x60 mm and 3.2 mm thick - was coated with the powder coating composition and thermoset to obtain a film of about 0.3 mm in thickness.
-' Measurements:
A DuPont-type impact tester was employed. A
semispherical striker of 1 kg weight having a head with a -, curvature radius of 1/4 inch was dropped onto the above s .
~r. 10 coated sample placed on the table having a semispherical hole with a curvature radic of about 1/4 inch to concavely deform the plate, and the dropping distance necessary to break and peel off the coating was measured. Those samples having the length of 30 cm or longer were evaluated to have a fair impact resistance.
(5) Specular gloss The same test piece used for measuring the impact strength was employed except that the film thickness is O.2 mm. The 60-degree specular gloss was measured according to the JIS Z-8741 standardi2ed method. Those having larger specular gloss are evaluated as having excellent surface smoothness. The values shown are values relative to that of the reference plane defined in the JIS
Z-8741 as 100.
1~ , .
~ - 14 -, , , .' .. , ,, . ' . ' ' . I . , , ., ,,, , , .. ,'. I, ., . : : .. , ', ' , ' . , ' ,. , 1327~6~
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O ~ -~ ~ O ~ o Z tU c" ~s m O ~
_I v ~ ~ ~ O P. E~
FIELD OF THE INVENTION
The present invention relates to an epoxy resin powder coating composition suitably used for the insulation of slots of motor rotors.
BACKGROUND OF THE INVENTION
~ poxy resin powder coating compositions are widely used for the insulation of electric and electronic equipments and parts. Examples are in JP-A-55-84371 and ~ 10 57-42760 (the term "JP-A" as used herein means an unexamined published Japanese patent application) which disclose powder coating compositions comprising a rubber modified epoxy resin, a hardener, and a filler. Those powder coating compositions are effective to form insulating films on smooth surfaces, however, are not satisfactory as insulating powder coating compositions for slots having edges such as in motor rotors and stators of ele~tric and electronic equipments and parts.
A temperature of 180C or higher is required to rapidly harden the epoxy resin to form insulating films on slots having edges. However, the aforesaid conventional epoxy resins, when heated under such a temperature condition, fail to form films with sufficient thickness on the edge parts, and, moreover, lack the necessary physical : '.
':
~ , 1327g~4 1 properties such as thermal resistance, adhesiv~ness, and impact resistance. In addition, surface smoothness is not attained.
SUMMARY OF THE INVENTION
The present invention aims to provide an epoxy resin powder coating composition which overcomes the aforesaid shortcomings of the conventional epoxy resin - powder coating compositions.
That is, the present invention provides an epoxy resin powder coating composition which comprises:
(A~ an epoxy resin comprising mainly of a bisphenol A type epoxy resin mixture of (a) a bi~phenol A type ,epoxy resin having a number average molecular weight of from 2, 500 to 8, 000 and ~b) a bisp~enol A type epoxy resin ~ 15 ~aving 8 number average molecular weight of from 350 eo 1 1,700, said ~ixeure baving a number average molecular weight of from 1~700 to 4,500;
(B~ rubber powder ~n an amount of 2 to 30 part~ -by weight per lOO parts by weiqht of said epoxy resin (A); ~' (C) at least one hardener; and (D) a filler. ' , , DETAILED EXPL~NATION OF THE INVENTION '~
The epoxy resin used in the present invention is j based on bisphenol A type epoxy resin. The bisphenol A ,~
1 25 type epoxy resin is pr.epared by blending a bisphenol A
! q~ epoxy ~#~n having a nu~ average leQ~ar weight of from 2,500 ~,','''',', .. ~ ....
, ~ ~' , .
1327~4 to 8,000 with that having a nu~r average m~lecular weight of from 350 to 1,700.
` The mixture has a n~r average molecular weight of from 1,700 to 4,500, preferably from 1,800 to 4,000, and more preferably from 2,000 to 3,000- When the n~r average molecular weight is less than 1,700, the edge coverage ' decreases, and when it exceeds 4,500, it is not appropriate since adhesiveness or surface smoothness of film is damaged and is apt to form pinholes.
` 10The bisphenol A type epoxy resin is a synthetic resin obtained by condensation polymerization of bisphenol A and epichlorohydrin, and is represented by general formula ~
. ..-15 ` O - C~13 ~ o~ C~3 0 CH2-CB-C~2 o~ CH2-1B-CB2 ~ ~ -CH2-CH-C~2 CH~ CB3 n wherein n is a degree of polymerization.
ffle bispx~ol A type ep~y resin a having a number average molecular weight of from 2,500 to 8,000 suitably used in the present invention has a melting point of from 120 to 160C, and pr~ably ~rom 130 to 150C. ffle nu~r average mol~ar weight of (a) is preferably from 2,700 to 6,S00.
. `D ~ ~
1327~4 The other bisperx)l A type epoxy resin b ~ving a nuT~er average molecular weight of from 350 to 1,700 has a melting point - of 100C or lower, preferably having a liquid phase at '3 ordinary temperature. The molecular weight of (b) is preferably from 30Q to 50Q.
A mixture of (a! and (b) is used for the present invention.
Also, a third different bisphenol A type epoxy resin with a nu~x~ average mole~i~r weight of ~mm 1,700 to 2,500 may be added in a small amount (generally, of from 5 to 40~ by weight, preferably from 5 to 35% by weight, and more preferably from 10 to 3Q~ by weight of the total amount of the epoxy resins) such that the nu~r average mole~ar weight ~ of the resulting mixture is in the range of from 1,700 to ¦ 15 4,500. Further, an epoxy resin of a different type may be ~ added in ~n amount of, generally from 5 to 40~ by weight, i preflerably from 5 to 35~ by weight, and more preferably from 10 to 30~ by weight of the totàl amount of the epoxy ~ resins.
¦ 20 Example of epoxy resins other than bisphenol A
type include polyfunctional epoxy resins having three or I more epoxy groups in the molecule. Such epo~y resinsinclude novolak type (o-cresol novolak type, phenol novolak type, etc.) e]poxy resins, triglicydyl ether epoxy type reslns ~epoxy co~npounds of cyanuric acid or . ',;.
-- 4 ~
`` 13~7~
1 triphenylpropane) and tetraglycidyl ether type epoxy resins (epoxy compounds of bisresorcinol F or tetraoxy tetraphenylethane, etc.).
, When the polyfunctional epoxy resin is used in the j 5 coating composition of the present invention, the proportion of the polyfunctional epoxy resin is generally from 5 to 40~ by wei~ht, preferably from 5 to 35% by w~ight, and more preferably from 10 to 30% by wei~ht of the total amount of the epoxy resins.
Other types of epoxy resins may be used in the present invention, provided that the epoxy resin other ~ than bisphenol A type should not be incorporated in an ¦ amount of more than 40% by weight of the total epoxy resin~ -3 15 In the powder coating composition of the present invention, rubber powder is blended. The content of the rubber powder in the coating composition is from 2 to 30 parts, preferably from 5 to 15 parts by weight per 100 parts by weight of the total amount of epoxy resin. This ¦ 20 relative content provides for a powder coating composition having a coating property especially improved in edge coverage and thermal resistance.
The rubber powder used in the present invention is essentially chemically inert to epoxy resin. Further, it .
:.
_ 5 _ - . "
1327~4 1 substantially disperses in the solid state when mixed with ; molten epoxy resin.
Examples of rubber powders are nitrile/butadiene t, based rubber (NBR), a chloroprene rubber, butadiene rubber, isoprene rubber, etc. The particle size of the rubber should be in the range of from about 100 to 500 ~m, ~ preferably from 130 to 250 ~m.
~~ When it is mixed with molten epoxy resin, it is preferable to use the rubber powder in a mixture with a filler, especially with calcium carbonate. The rubber powder is better dispersed in molten epoxy resin when used `
as a mixture. Moreover, rubber powder is more readily ~ ground to fine powder and the filler incorporated in the `2~ mixture avoids blocking of the finely ground rubber .,.
po~der.
The amount of filler added is preferably from 5 to `
25 parts, and more pre$erably from 10 to 20 parts, by weight, per 100 parts by weight of rùbber powder. `
The hardener to be blended with the powder coating composition of the present invention includes those conventiona~ly usedr such as aromatic amines, acid anhydrides, guanidines (dicyandiamide, etc.), and imidazoles. To achieve optimal gloss, adhesiveness and I edge coverage, two or more hardeners having different hardening speed can be appropriately blended to give a - ;
',,`.
.,.
i - 6 -?~ . .
,' ' ' .
1 mixture of hardeners with controlled hardening speed. Too high a hardening speed results in a hardener which gives a dull coatin~ with poor adhesiveness, and too low a speed results in poor edge coverage. The amount of hardener added differs according to the type. An example is an s imidazole type hardener which is added in an amount of from O.l to 5 parts, preferably from 0.2 to 4 parts by weight per lO0 parts by weight of the total amount of the epoxy resins.
~ lO In the case of using a combination of hardeners havinq different hardening speed, the high speed hardener can function as a hardening promoter to the low speed hardener.
Specific examples of the low speed hardeners include 2-methyl imidazole, diaminodiphenylsulfone, ¦ diaminodiphenylether, etc.
Specfic examples of the high speed hardeners include 2,4-diamino-6-12'-methylimidazolyl (l)]ethyl-s-triazine, 2-phenyl imida20le, 2-ethyl-4-methyl imidazole, etc~
When a mixture of two or more hardeners having different hardening speed is employed, the combination of ¦ an imidazole type high speed hardener with a low speed ! hardener chosen from ~elow is preferred.
1327~4 1 Examples of imidazole compounds that are high speed hardeners can be expressed in accordance with general formula (II);
Rl-N ~ (II) R
, wherein Rl represents a hydro~en atom or an alkyl group - -substituted with an aryl group (e.g., -CH2- ~ ), and R2 represents a substituted or unsubstituted alkyl group (e.g., CH3, C~Hs, CH(CH3)2, CllH23, C~H35) or an aryl group te.g... phenyl, tolyl, xylyl). Preferably, the alkyl `
group has 1 to 20 carbon atoms and the aryl group has 6 to 20 carbon atoms.
Examples of imidazole compounds that are low speed hardeners can be expressed in accordance with general ~ormula (III);
~ ,'~'.
!
. . .
.
A
.~ ......
1327~4 R3-N ~ (III) 1 wherein R3 represents an alkyl group substituted with a cyano group (e.g., C~2C~2CN) or a group of CH2CH2 ~ ~ , and R~ represents a substituted or unsubstituted alkyl group (e.g., CH3, C2~5, CH(CH3)2, ~23- Cl7~3s) or an aryl group (e.g~, phenyl, tolyl, ..
xylyl3. Preferably, thle alkyl group has 1 to 20 carbon atoms and the aryl group has 6 to 20 carbon atoms.
In the case of using a combination of imidazole type hardeners, preferably O.OS to 0.7 part by weight of a high speed hardener is used with 0.5 to 3 parts by weight of a low speed hardener per 100 parts by weight of the total amount of epoxy resins.
lS Inorganic }illers suitably blended with the composition of the present invention include silica, calcium carbonate, alumina, clay, mica, talc, and powdered glass fibers. ~he amount to be blended is generally from 5~ ' ''f ' ,`' _ 9 - ' ' .
~3276~4 :`
1 10 to 80%, and preferably from 20 to 50~, by weight, of the total weight of the powder coating composition.
Conventional additives such as leveling agents (e.g., acrylic acid ester oligomers), pigments (e.g., Cr203, Fe203), impact resistance improvers (e.g., butadiene-acrylonitrile copolymer, butyral resin), and hardening promoters (e.g~, 2-phenylimidazole, 2-ethyl-4-methylimidazole) may be appropriately blended with the powder coating composition of the present invention.
Conventional methods can be used to blend the components of the epoxy resin powder coating composition of the present invention. For example, the components can be dry-mixed with a mixer or the like, melt-mixed using a kneader or the like, or solidified by cooling after melt-mixed usinq an extruder or the like, and then ground to :
fine particles.
The present invention is hereinafter described in qreater detail with reference to the examples, which are not to be construed as limiting the scope thereof. Unless otherwise indicated, all parts, percents and ratios are by weight.
Epoxy resin powder coating compositions as shown in Table 1 were prepared. The following are the explanations for ~he c:omponents in Table 1.
: :
.
, ~ :
~ .
13276~
Epikote 1007*: a bisp~enol-A type epoxy resin having a n ~ er average molecular wei~ht of about 2,900, with a melting point of 128C; from Yuka Shell Epoxy Co. Ltd.
EOCN 104*: an o-cresol novolak type epoxy resin having a softening point of 95C; from Nippon Kayaku Co~ Ltd.
Epikote lQ04*: a bisp~enol-A type epo~cy resin having a n ~ er average molecular weight of about 1,600, with a ~ 10 melting point of 98C; from Yuka Shell ,~ Epoxy Co. Ltd.
Rubber modified epoxy resin: ~ -an epoxy resin modified with a liquid nitrile rubber having a -COOH group at the end, with a melting point of 100C; ~ -Epomic SR-35K from Mitsui Petro-~ chemicals Industries , Ltd.
`~ Rubbçr Powder: a mixture containing 87% by weight of rubber having a Mooney viscosity of 75 to 85 and 13% by weight of calcium carbonate; the calcium carbonate powder is substantially adhered on the surface of the rubber particles. ~he particle distribution is as follows:
, 25 0~5% of over 35 ~m mesh, 2.5% of over j *Trade Mark ` :.
`1 `
D ;:
1 3 2 7 ~ 6 4i .` 1 42 ~m mesh, 22% of over 60 ~ mesh, 43%
~x of over 80 ~m mesh, 18.5~i of over 125 -~ ~m mesh, and 13.5% of under 125 ~m ~? mesh. HI-BLOW HF-21~ from Nippon Zeon Co., Ltd.
Hycar-CTsN*: a butadiene-acrylonitrile copolymer with carboxyl groups at both ends, having a viscosity of l,200 poises at 27C; from ~he B.F. Goodrich Chemical -Corp.
Leveling agent: an acrylic ester oligomer Hardener A: 2-methylimidazole Hardener B: 2~4-diamino-6-[2'-methylimidazolyl (l,?3ethyl-s-triazine lS DAM: 4,4'-diaminodiphenylmethane AD~: Adipic acid dihydrazide `
Then, each of the aforesaid samples were coated on slots of motor rotors at 180 to 260C usin~ a flow-imm~rsion method, and the properties ~of each of the obtained films were investigated using the methods as follows. Thè results are given in Table 2.
(l) Edge coverage :.:
A half-inch square bar was coated with the powder coating composition at a thickness of about 0.3 mm and subjected to ASTM D-2916~ standardized measurements. Those *Trade Mark ? 12 -B
~.
1327~6~
1 having hisher ratio (%) are evaluated as having excellent edge coverage.
~2) Thermal resistance A metal mold having a concave of 12.7 mm width, 170 mm length, and 12.7 mm depth was first heated to 160 !~ to 170C, then, the powder coating composition was applied } to the heated metal mold for 10 to 15 minutes, then molded, and thermoset at 170C for 20 minutes. The heat deformation temperature (~DT) of the hardened body was ;~ 10 obtained according to the ~STM D-648 standard. Those having higher HDTs have higher thermal resistances.
~t ( 3) Adhesiveness Two degreased test pieces ~soft steel plates of 100 mmx20 mmx3 mm) were heated to about 200C. The powder coating co~position was adhered in molten state on the upper surface (20 mm wide and about 15 mm long) of the tip of the either test piece, and was applied to the tip ~20 mm wide and 10 mm long) of the other test piece under load of 1 kg at 200C for 10 minutes to harden by heating.
Then, the test pieces were left at room temperature and the tensile` stren~th at which the joint broke was measured. Those having larger strenqth are evaluated as having excellent adhesiveness.
-t . :
1327~
1 ~4) Impact resistance Preparation of the coated test piece:
~ A soft steel plate of 60x60 mm and 3.2 mm thick - was coated with the powder coating composition and thermoset to obtain a film of about 0.3 mm in thickness.
-' Measurements:
A DuPont-type impact tester was employed. A
semispherical striker of 1 kg weight having a head with a -, curvature radius of 1/4 inch was dropped onto the above s .
~r. 10 coated sample placed on the table having a semispherical hole with a curvature radic of about 1/4 inch to concavely deform the plate, and the dropping distance necessary to break and peel off the coating was measured. Those samples having the length of 30 cm or longer were evaluated to have a fair impact resistance.
(5) Specular gloss The same test piece used for measuring the impact strength was employed except that the film thickness is O.2 mm. The 60-degree specular gloss was measured according to the JIS Z-8741 standardi2ed method. Those having larger specular gloss are evaluated as having excellent surface smoothness. The values shown are values relative to that of the reference plane defined in the JIS
Z-8741 as 100.
1~ , .
~ - 14 -, , , .' .. , ,, . ' . ' ' . I . , , ., ,,, , , .. ,'. I, ., . : : .. , ', ' , ' . , ' ,. , 1327~6~
' ~ ~ ~ ~ o o o . ~ oo o , , ~ o o o , . In N t~ O O O
~1 Io ~ I I L ) O O
., ~ ~ ~r o ~ O O o I I ~ O O o _l I I
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~ ~ ~ ell O
.~ ~ ~ O I O I I U~ O O~1 1 1 ~
o N ~r~r O
~ol o o o ~ o o o ~
ol O O O I N r ) O O O
O N ~ O O O
O O I ~
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Nl O O O I O I Ul O O _i I I ~ a~
U~ N ~) O O O Ql _l O O o I ~ I ~ o o ~ 115 ~ o o ~ ~ L ` ~
O ~ -~ ~ O ~ o Z tU c" ~s m O ~
_I v ~ ~ ~ O P. E~
3 ~u o ~uQ. U E~ ~ ~u t o o .Q x Z xR ~ -~ Q la U ~ tD ~ ~ o ~h --I t~ --I .a tu m .a u ~
O O V~ ~ æ ~ U p ~ % c~ -t,~, ~ , ~, - 13276~4 , o O ~ o a~
~1 N O
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,~ , t~ ~P O ~ ~ C~
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o ~o N Ul N N d' o r~ ') o . E~l ¦ H ~ N ~ ~ ~
O N 1-~ 0 0 t~ O _I N
~ I
O
H ~r U~ Ir) In It' ~ ~ N ~ ~ Cl~
~1 0 ~
O O V~ ~ æ ~ U p ~ % c~ -t,~, ~ , ~, - 13276~4 , o O ~ o a~
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,~ , t~ ~P O ~ ~ C~
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o ~o N Ul N N d' o r~ ') o . E~l ¦ H ~ N ~ ~ ~
O N 1-~ 0 0 t~ O _I N
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~1 0 ~
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U ~ ~ ~
O ~ n o c,~
o ~ ~U-~r V -- 1 6 -- ~:
.
~3276~
1 It is apparent from the results shown in Table 2 that coating composition samples according to the present invention show well-balanced results.
Powder coating compositions having the same composition as that of sample No. 3 in Example 1 were prepared except that the bisphenol A type epoxy resin varied molecular weight was substituted for the Epikote 1004*. The edge coverage for the samples was measured and the results are given with refe~e to the nu~ber average lecular weight in ~able 3. The epoxy resins used are as follows.
A A S0;10 mixture by weight of Epikote 828*
~` (num~er average le~ar weight of about 380) and Epikote 1007*
(number average molecNlar weight of about 2,900) lS B A 4-~:17 mixture by ~ei~ht of Epikote 828 ~ ~number average molecular weight of akout 380) and Ep~kote 1007 `~ (nu~r average mol~ar weight of about 2,900).
C A 13:47 mixture by wei~ht of Epikote 828 (nuIber average mol~ar weight of about 380~ ikote 1009*
(nu~x~ average le~ar weight of about 3,800).
D A 8:52 mixture by weight of Epi~ote 1001*
(nu~x~ average molecular weight of about 900) and bdsphenol A
type epoxy resin synthesized by a conventional .
~e~x~ (number~verage molecular weight of akout 6,000)~
~Trade Mark ~ ' ~ ;"
D - 17 - `
.
-~, .
1327~64 , , ~ 1 E sisphenol A type epoxy resin synthesized by a - con~entional me~od (n~#r average m~lecular weight of about 6,000) The n~r average molecular weightin Table 3 are given for the mixture of bisphenol A type epoxy resins.
s Table 3 * 2 3 4 5*
~ ~poxy resin A B C D E
_I~ 10 ~w~r average molecular weight1,500 1,700 3,000 4,500 5,000 Edge coverage l%)30 56 69 71 84 Adhesiveness (kg~cm2)230 235 240 201 191 ~.
It is apparent from the results shown in Tab}e 3 that coating composition samples according to the present invention show well-balancèd results.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various ~ -changes and modifications can be made therein without departing ~rom the splrit and scope thereoF.
;
I
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~. - 18 -,.~,". .'',''.
U ~ ~ ~
O ~ n o c,~
o ~ ~U-~r V -- 1 6 -- ~:
.
~3276~
1 It is apparent from the results shown in Table 2 that coating composition samples according to the present invention show well-balanced results.
Powder coating compositions having the same composition as that of sample No. 3 in Example 1 were prepared except that the bisphenol A type epoxy resin varied molecular weight was substituted for the Epikote 1004*. The edge coverage for the samples was measured and the results are given with refe~e to the nu~ber average lecular weight in ~able 3. The epoxy resins used are as follows.
A A S0;10 mixture by weight of Epikote 828*
~` (num~er average le~ar weight of about 380) and Epikote 1007*
(number average molecNlar weight of about 2,900) lS B A 4-~:17 mixture by ~ei~ht of Epikote 828 ~ ~number average molecular weight of akout 380) and Ep~kote 1007 `~ (nu~r average mol~ar weight of about 2,900).
C A 13:47 mixture by wei~ht of Epikote 828 (nuIber average mol~ar weight of about 380~ ikote 1009*
(nu~x~ average le~ar weight of about 3,800).
D A 8:52 mixture by weight of Epi~ote 1001*
(nu~x~ average molecular weight of about 900) and bdsphenol A
type epoxy resin synthesized by a conventional .
~e~x~ (number~verage molecular weight of akout 6,000)~
~Trade Mark ~ ' ~ ;"
D - 17 - `
.
-~, .
1327~64 , , ~ 1 E sisphenol A type epoxy resin synthesized by a - con~entional me~od (n~#r average m~lecular weight of about 6,000) The n~r average molecular weightin Table 3 are given for the mixture of bisphenol A type epoxy resins.
s Table 3 * 2 3 4 5*
~ ~poxy resin A B C D E
_I~ 10 ~w~r average molecular weight1,500 1,700 3,000 4,500 5,000 Edge coverage l%)30 56 69 71 84 Adhesiveness (kg~cm2)230 235 240 201 191 ~.
It is apparent from the results shown in Tab}e 3 that coating composition samples according to the present invention show well-balancèd results.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various ~ -changes and modifications can be made therein without departing ~rom the splrit and scope thereoF.
;
I
..
~. - 18 -,.~,". .'',''.
Claims (19)
1. An epoxy resin powder coating composition which comprises:
(A) an epoxy resin comprising mainly of a bisphenol A type epoxy resin mixture of (a) a bisphenol A
type epoxy resin having a number average molecular weight of from 2,500 to 8,000 and (b) a bisphenol A type epoxy resin having a number average molecular weight of from 350 to 1,700, said mixture having a number average molecular weight of from 1,700 to 4,500;
(B) rubber powder in an amount of 2 to 30 parts by weight per 100 parts by weight of said epoxy resin (A);
(C) at least one hardener; and (D) a filler.
(A) an epoxy resin comprising mainly of a bisphenol A type epoxy resin mixture of (a) a bisphenol A
type epoxy resin having a number average molecular weight of from 2,500 to 8,000 and (b) a bisphenol A type epoxy resin having a number average molecular weight of from 350 to 1,700, said mixture having a number average molecular weight of from 1,700 to 4,500;
(B) rubber powder in an amount of 2 to 30 parts by weight per 100 parts by weight of said epoxy resin (A);
(C) at least one hardener; and (D) a filler.
2. An epoxy resin powder coating composition as in Claim 1, wherein the number average molecular weight of said bisphenol A type epoxy resin mixture is from 1,800 to 4,000.
3. An epoxy resin powder coating composition as in Claim 2, wherein the number average molecular weight of said bisphenol A type epoxy resin mixture is from 2,000 to 3,000.
4. An epoxy resin powder coating composition as in Claim 1, wherein the number average molecular weight of (b) is from 350 to 500.
5. An epoxy resin powder coating composition as in claim 1, wherein the number average molecular weight of (b) is from 800 to 1,700.
6. An epoxy resin powder coating composition as in Claim 1 further comprising a bisphenol A type epoxy resin having a number average molecular weight of from 1,700 to 2,500.
7. An epoxy resin powder coating composition as in Claim 1 further comprising a polyfunctional epoxy resin having three or more epoxy groups in the molecule in an amount of from 5 to 40% by weight of the total amount of the epoxy resins.
8. An epoxy resin powder coating composition as in Claim 7, wherein said polyfunctional epoxy resin is selected from the group consisting of novolak type epoxy resins, triglicydyl ether type epoxy resins and tetraglicydyl ether type epoxy resins.
9. An epoxy resin powder coating composition as in Claim 1, wherein said rubber powder has a particle size in the range of from about 100 to 500 µm.
10. An epoxy resin powder coating composition as in Claim 1, wherein said filler is calcium carbonate.
11. An epoxy resin powder coating composition as in Claim 1, wherein said filler is present in an amount of from 5 to 25 parts by weight per 100 parts by weight of rubber powder.
12. An epoxy resin powder coating composition as in Claim 1, wherein said hardener comprises an imidazole compound which is contained in said composition in an amount of from 0.1 to 5 parts by weight per 100 parts by weight of the total amount of the epoxy resins.
13. An epoxy resin powder coating composition as in Claim 12, wherein said imidazole compound is a high speed hardener represented by general formula (II):
(II) wherein R1 represents a hydrogen atom or an alkyl group substituted with an aryl group, and R2 represents a substituted or unsubstituted alkyl group or an aryl group.
(II) wherein R1 represents a hydrogen atom or an alkyl group substituted with an aryl group, and R2 represents a substituted or unsubstituted alkyl group or an aryl group.
14. An epoxy resin powder coating composition as in Claim 13, wherein said hardener further comprises a low speed hardener represented by general formula (III):
(III) wherein R3 represents an alkyl group substituted with a cyano group and R4 represents a substituted or unsubstituted alkyl group or an aryl group.
(III) wherein R3 represents an alkyl group substituted with a cyano group and R4 represents a substituted or unsubstituted alkyl group or an aryl group.
15. An epoxy resin powder coating composition as in Claim 14, wherein the amount of said high speed hardener is from 0.05 to 0.7 part by weight per 100 parts by weight of the total amount of epoxy resins and the amount of said low speed hardener is from 0.5 to 3 parts by weight per 100 parts by weight of the total amount of epoxy resins.
16. An epoxy resin powder coating composition as claimed in claim 1 wherein said rubber powder is selected from the group consisting of nitrile/butadiene based rubber, chloroprene rubber, butadiene rubber and isoprene rubber.
17. An epoxy resin powder coating composition as claimed in claim 1 wherein said hardener is selected from the group consisting of aromatic amines, acid anhydrides and guanidines.
18. An epoxy resin powder coating composition as claimed in claim 16 wherein said hardener is selected from the group consisting of aromatic amines, acid anhydrides and guanidines.
19. An epoxy resin powder coating composition as claimed in one of claim 1, 16, 17 or 18 wherein said fillers are selected from the group consisting of silica, calcium carbonate, alumina, clay, mica, talc and powdered glass fibers.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62066296A JPH07103343B2 (en) | 1987-03-20 | 1987-03-20 | Epoxy resin powder coating suitable for slot insulation |
| CA000577239A CA1327664C (en) | 1987-03-20 | 1988-09-13 | Epoxy resin powder coating composition |
| US07/412,616 US4933382A (en) | 1987-03-20 | 1989-09-26 | Epoxy resin powder coating composition |
| US07/764,101 US5153239A (en) | 1987-02-07 | 1991-09-05 | Epoxy resin powder coating containing imidazole trimellitates |
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62066296A JPH07103343B2 (en) | 1987-03-20 | 1987-03-20 | Epoxy resin powder coating suitable for slot insulation |
| US22941388A | 1988-08-08 | 1988-08-08 | |
| CA000577239A CA1327664C (en) | 1987-03-20 | 1988-09-13 | Epoxy resin powder coating composition |
| US24683888A | 1988-09-20 | 1988-09-20 | |
| US07/412,616 US4933382A (en) | 1987-03-20 | 1989-09-26 | Epoxy resin powder coating composition |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1327664C true CA1327664C (en) | 1994-03-08 |
Family
ID=27508317
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000577239A Expired - Fee Related CA1327664C (en) | 1987-02-07 | 1988-09-13 | Epoxy resin powder coating composition |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1327664C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103601870A (en) * | 2013-11-15 | 2014-02-26 | 宏昌电子材料股份有限公司 | Epoxy resin for low-gloss powder paint, and preparation method and application thereof |
| CN113039231A (en) * | 2018-12-14 | 2021-06-25 | Swimc有限公司 | Fusion bonded epoxy amine rebar powder coating |
-
1988
- 1988-09-13 CA CA000577239A patent/CA1327664C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103601870A (en) * | 2013-11-15 | 2014-02-26 | 宏昌电子材料股份有限公司 | Epoxy resin for low-gloss powder paint, and preparation method and application thereof |
| CN103601870B (en) * | 2013-11-15 | 2016-01-20 | 珠海宏昌电子材料有限公司 | A kind of low gloss powder coating epoxy resin and its preparation method and application |
| CN113039231A (en) * | 2018-12-14 | 2021-06-25 | Swimc有限公司 | Fusion bonded epoxy amine rebar powder coating |
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