JP6902839B2 - Powder paint - Google Patents
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- JP6902839B2 JP6902839B2 JP2016182124A JP2016182124A JP6902839B2 JP 6902839 B2 JP6902839 B2 JP 6902839B2 JP 2016182124 A JP2016182124 A JP 2016182124A JP 2016182124 A JP2016182124 A JP 2016182124A JP 6902839 B2 JP6902839 B2 JP 6902839B2
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- Prior art keywords
- powder coating
- coating material
- epoxy resin
- core
- type epoxy
- Prior art date
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- 239000000843 powder Substances 0.000 title claims description 96
- 239000003973 paint Substances 0.000 title description 2
- 238000000576 coating method Methods 0.000 claims description 131
- 239000011248 coating agent Substances 0.000 claims description 125
- 239000000463 material Substances 0.000 claims description 78
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 62
- 239000003822 epoxy resin Substances 0.000 claims description 60
- 229920000647 polyepoxide Polymers 0.000 claims description 60
- IISBACLAFKSPIT-UHFFFAOYSA-N bisphenol A Chemical compound C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 IISBACLAFKSPIT-UHFFFAOYSA-N 0.000 claims description 52
- 239000002245 particle Substances 0.000 claims description 32
- 239000000377 silicon dioxide Substances 0.000 claims description 26
- 239000011258 core-shell material Substances 0.000 claims description 25
- 229920003986 novolac Polymers 0.000 claims description 25
- QTWJRLJHJPIABL-UHFFFAOYSA-N 2-methylphenol;3-methylphenol;4-methylphenol Chemical compound CC1=CC=C(O)C=C1.CC1=CC=CC(O)=C1.CC1=CC=CC=C1O QTWJRLJHJPIABL-UHFFFAOYSA-N 0.000 claims description 23
- 229930003836 cresol Natural products 0.000 claims description 23
- 239000000203 mixture Substances 0.000 claims description 23
- 230000009477 glass transition Effects 0.000 claims description 22
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 claims description 6
- 239000011162 core material Substances 0.000 description 22
- 230000000052 comparative effect Effects 0.000 description 18
- 239000003795 chemical substances by application Substances 0.000 description 15
- 238000011156 evaluation Methods 0.000 description 12
- 239000000945 filler Substances 0.000 description 11
- 230000035939 shock Effects 0.000 description 10
- 239000004593 Epoxy Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 9
- 239000010410 layer Substances 0.000 description 9
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 238000002156 mixing Methods 0.000 description 8
- 229910000831 Steel Inorganic materials 0.000 description 7
- 229920005989 resin Polymers 0.000 description 7
- 239000011347 resin Substances 0.000 description 7
- 239000010959 steel Substances 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 6
- -1 imidazole azine derivatives Chemical class 0.000 description 5
- 239000000155 melt Substances 0.000 description 5
- 230000000116 mitigating effect Effects 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 description 4
- 229910000019 calcium carbonate Inorganic materials 0.000 description 4
- QGBSISYHAICWAH-UHFFFAOYSA-N dicyandiamide Chemical compound NC(N)=NC#N QGBSISYHAICWAH-UHFFFAOYSA-N 0.000 description 4
- 229920000642 polymer Polymers 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000004804 winding Methods 0.000 description 4
- FVCSARBUZVPSQF-UHFFFAOYSA-N 5-(2,4-dioxooxolan-3-yl)-7-methyl-3a,4,5,7a-tetrahydro-2-benzofuran-1,3-dione Chemical compound C1C(C(OC2=O)=O)C2C(C)=CC1C1C(=O)COC1=O FVCSARBUZVPSQF-UHFFFAOYSA-N 0.000 description 3
- 239000000654 additive Substances 0.000 description 3
- 229920001577 copolymer Polymers 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- KUBDPQJOLOUJRM-UHFFFAOYSA-N 2-(chloromethyl)oxirane;4-[2-(4-hydroxyphenyl)propan-2-yl]phenol Chemical compound ClCC1CO1.C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 KUBDPQJOLOUJRM-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- RRHGJUQNOFWUDK-UHFFFAOYSA-N Isoprene Chemical compound CC(=C)C=C RRHGJUQNOFWUDK-UHFFFAOYSA-N 0.000 description 2
- 239000004793 Polystyrene Substances 0.000 description 2
- 239000006096 absorbing agent Substances 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 125000005396 acrylic acid ester group Chemical group 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 150000001412 amines Chemical class 0.000 description 2
- 150000004982 aromatic amines Chemical class 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000012792 core layer Substances 0.000 description 2
- 239000007822 coupling agent Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 150000002148 esters Chemical class 0.000 description 2
- 238000005227 gel permeation chromatography Methods 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 2
- RAXXELZNTBOGNW-UHFFFAOYSA-N imidazole Natural products C1=CNC=N1 RAXXELZNTBOGNW-UHFFFAOYSA-N 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 239000011256 inorganic filler Substances 0.000 description 2
- 229910003475 inorganic filler Inorganic materials 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 230000000379 polymerizing effect Effects 0.000 description 2
- 229920001296 polysiloxane Polymers 0.000 description 2
- 229920002223 polystyrene Polymers 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 230000000930 thermomechanical effect Effects 0.000 description 2
- CWERGRDVMFNCDR-UHFFFAOYSA-N thioglycolic acid Chemical compound OC(=O)CS CWERGRDVMFNCDR-UHFFFAOYSA-N 0.000 description 2
- UMGDCJDMYOKAJW-UHFFFAOYSA-N thiourea Chemical compound NC(N)=S UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 description 2
- IMNIMPAHZVJRPE-UHFFFAOYSA-N triethylenediamine Chemical compound C1CN2CCN1CC2 IMNIMPAHZVJRPE-UHFFFAOYSA-N 0.000 description 2
- MUTGBJKUEZFXGO-OLQVQODUSA-N (3as,7ar)-3a,4,5,6,7,7a-hexahydro-2-benzofuran-1,3-dione Chemical compound C1CCC[C@@H]2C(=O)OC(=O)[C@@H]21 MUTGBJKUEZFXGO-OLQVQODUSA-N 0.000 description 1
- KMOUUZVZFBCRAM-OLQVQODUSA-N (3as,7ar)-3a,4,7,7a-tetrahydro-2-benzofuran-1,3-dione Chemical compound C1C=CC[C@@H]2C(=O)OC(=O)[C@@H]21 KMOUUZVZFBCRAM-OLQVQODUSA-N 0.000 description 1
- WZCQRUWWHSTZEM-UHFFFAOYSA-N 1,3-phenylenediamine Chemical compound NC1=CC=CC(N)=C1 WZCQRUWWHSTZEM-UHFFFAOYSA-N 0.000 description 1
- IVYDZBRMECSWSH-UHFFFAOYSA-N 1-(hydrazinecarbonyl)naphthalene-2-carboxylic acid Chemical compound C1=CC=C2C(C(=O)NN)=C(C(O)=O)C=CC2=C1 IVYDZBRMECSWSH-UHFFFAOYSA-N 0.000 description 1
- VILCJCGEZXAXTO-UHFFFAOYSA-N 2,2,2-tetramine Chemical compound NCCNCCNCCN VILCJCGEZXAXTO-UHFFFAOYSA-N 0.000 description 1
- LXBGSDVWAMZHDD-UHFFFAOYSA-N 2-methyl-1h-imidazole Chemical compound CC1=NC=CN1 LXBGSDVWAMZHDD-UHFFFAOYSA-N 0.000 description 1
- LJGHYPLBDBRCRZ-UHFFFAOYSA-N 3-(3-aminophenyl)sulfonylaniline Chemical compound NC1=CC=CC(S(=O)(=O)C=2C=C(N)C=CC=2)=C1 LJGHYPLBDBRCRZ-UHFFFAOYSA-N 0.000 description 1
- RNLHGQLZWXBQNY-UHFFFAOYSA-N 3-(aminomethyl)-3,5,5-trimethylcyclohexan-1-amine Chemical compound CC1(C)CC(N)CC(C)(CN)C1 RNLHGQLZWXBQNY-UHFFFAOYSA-N 0.000 description 1
- YBRVSVVVWCFQMG-UHFFFAOYSA-N 4,4'-diaminodiphenylmethane Chemical compound C1=CC(N)=CC=C1CC1=CC=C(N)C=C1 YBRVSVVVWCFQMG-UHFFFAOYSA-N 0.000 description 1
- DZIHTWJGPDVSGE-UHFFFAOYSA-N 4-[(4-aminocyclohexyl)methyl]cyclohexan-1-amine Chemical compound C1CC(N)CCC1CC1CCC(N)CC1 DZIHTWJGPDVSGE-UHFFFAOYSA-N 0.000 description 1
- ULKLGIFJWFIQFF-UHFFFAOYSA-N 5K8XI641G3 Chemical compound CCC1=NC=C(C)N1 ULKLGIFJWFIQFF-UHFFFAOYSA-N 0.000 description 1
- ALEBYBVYXQTORU-UHFFFAOYSA-N 6-hydrazinyl-6-oxohexanoic acid Chemical compound NNC(=O)CCCCC(O)=O ALEBYBVYXQTORU-UHFFFAOYSA-N 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- MQJKPEGWNLWLTK-UHFFFAOYSA-N Dapsone Chemical compound C1=CC(N)=CC=C1S(=O)(=O)C1=CC=C(N)C=C1 MQJKPEGWNLWLTK-UHFFFAOYSA-N 0.000 description 1
- RPNUMPOLZDHAAY-UHFFFAOYSA-N Diethylenetriamine Chemical compound NCCNCCN RPNUMPOLZDHAAY-UHFFFAOYSA-N 0.000 description 1
- 239000002841 Lewis acid Substances 0.000 description 1
- JLTDJTHDQAWBAV-UHFFFAOYSA-N N,N-dimethylaniline Chemical compound CN(C)C1=CC=CC=C1 JLTDJTHDQAWBAV-UHFFFAOYSA-N 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 229920002873 Polyethylenimine Polymers 0.000 description 1
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Natural products C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 1
- 239000007983 Tris buffer Substances 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Natural products NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- FDLQZKYLHJJBHD-UHFFFAOYSA-N [3-(aminomethyl)phenyl]methanamine Chemical compound NCC1=CC=CC(CN)=C1 FDLQZKYLHJJBHD-UHFFFAOYSA-N 0.000 description 1
- 150000008065 acid anhydrides Chemical class 0.000 description 1
- 229920001893 acrylonitrile styrene Polymers 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 125000004202 aminomethyl group Chemical group [H]N([H])C([H])([H])* 0.000 description 1
- 150000008064 anhydrides Chemical class 0.000 description 1
- 239000000378 calcium silicate Substances 0.000 description 1
- 229910052918 calcium silicate Inorganic materials 0.000 description 1
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 239000008199 coating composition Substances 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 229910002026 crystalline silica Inorganic materials 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 150000001993 dienes Chemical class 0.000 description 1
- 239000000539 dimer Substances 0.000 description 1
- 125000006222 dimethylaminomethyl group Chemical group [H]C([H])([H])N(C([H])([H])[H])C([H])([H])* 0.000 description 1
- XXBDWLFCJWSEKW-UHFFFAOYSA-N dimethylbenzylamine Chemical compound CN(C)CC1=CC=CC=C1 XXBDWLFCJWSEKW-UHFFFAOYSA-N 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 238000009503 electrostatic coating Methods 0.000 description 1
- 238000010556 emulsion polymerization method Methods 0.000 description 1
- 125000003700 epoxy group Chemical group 0.000 description 1
- JDVIRCVIXCMTPU-UHFFFAOYSA-N ethanamine;trifluoroborane Chemical compound CCN.FB(F)F JDVIRCVIXCMTPU-UHFFFAOYSA-N 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000005350 fused silica glass Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229940042795 hydrazides for tuberculosis treatment Drugs 0.000 description 1
- 150000002460 imidazoles Chemical class 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000009863 impact test Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000007561 laser diffraction method Methods 0.000 description 1
- 150000007517 lewis acids Chemical class 0.000 description 1
- 229940018564 m-phenylenediamine Drugs 0.000 description 1
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 1
- 239000010445 mica Substances 0.000 description 1
- 229910052618 mica group Inorganic materials 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000004843 novolac epoxy resin Substances 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 150000002989 phenols Chemical class 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 229920006122 polyamide resin Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 229920005862 polyol Polymers 0.000 description 1
- 150000003077 polyols Chemical class 0.000 description 1
- 235000013824 polyphenols Nutrition 0.000 description 1
- SCUZVMOVTVSBLE-UHFFFAOYSA-N prop-2-enenitrile;styrene Chemical compound C=CC#N.C=CC1=CC=CC=C1 SCUZVMOVTVSBLE-UHFFFAOYSA-N 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011342 resin composition Substances 0.000 description 1
- 238000007665 sagging Methods 0.000 description 1
- 238000000790 scattering method Methods 0.000 description 1
- 239000011359 shock absorbing material Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 229920002379 silicone rubber Polymers 0.000 description 1
- 239000004945 silicone rubber Substances 0.000 description 1
- 239000010421 standard material Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 150000003512 tertiary amines Chemical class 0.000 description 1
- 238000002411 thermogravimetry Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Paints Or Removers (AREA)
- Insulation, Fastening Of Motor, Generator Windings (AREA)
Description
本発明は、粉体塗料に関し、特にコイルの固着材として好適な粉体塗料に関する。 The present invention relates to a powder coating material, and more particularly to a powder coating material suitable as a fixing material for a coil.
電動機や発電機等の回転子（電機子）のコア空間内には、巻成したコイルが設置されている。回転によりコイルの巻線がばらけたり、巻線同士、又は巻線とティース部との摩擦や衝突により、巻線の被覆が剥がれて短絡するのを防止するため、コイルはコア空間内に固着されている。このようにコイルを固着させるためには、エポキシ系粉体塗料が用いられてきた。 A wound coil is installed in the core space of a rotor (armature) such as an electric motor or a generator. The coil is fixed in the core space to prevent the coil windings from loosening due to rotation, or from friction or collision between the windings or between the windings and the teeth, causing the windings to peel off and short-circuit. Has been done. Epoxy powder coatings have been used to fix the coils in this way.
特許文献１には、平均分子量９００〜１６００のビスフェノールＡ型エポキシ樹脂８０〜９８重量部と分子内にエポキシ基を３個以上有する多官能エポキシ樹脂２〜２０重量部とからなる混合エポキシ樹脂１００重量部と、ジシアンジアミド２〜１０重量部と、イミダゾール類アジン誘導体０．２〜２重量部又は尿素誘導体化合物１〜４重量部と、無機充填剤５０〜２５０重量部とからなるエポキシ樹脂粉体塗料が開示されている。特許文献１の粉体塗料では、（１）溶融物の流れ性がよいため、コア空間内に良好に充填されること、（２）粉体塗料のコア等への密着性がよく耐熱性に優れるため、運転時に発生する熱が蓄積して回転子の温度が上昇しても、硬化樹脂によるコイルの強い接着固定力を維持できること、及び（３）硬化樹脂の切削性がよいので、コア表面の余分の硬化樹脂を切削除去処理する作業が容易であることが記載されている。
しかしながら、特許文献１の粉体塗料では、初期クラックが発生する可能性があることが確認されている。また、特許文献１の粉体塗料では、得られる硬化物の耐熱性に限界があり、さらに高温になる電機子への適用は困難と考えられる。
Patent Document 1 describes 100 parts by weight of a mixed epoxy resin consisting of 80 to 98 parts by weight of a bisphenol A type epoxy resin having an average molecular weight of 900 to 1600 and 2 to 20 parts by weight of a polyfunctional epoxy resin having three or more epoxy groups in the molecule. parts and, dicyandiamide 2-10 parts by weight, and 0.2 to 2 parts by weight of an imidazole azine derivatives or urea derivative compound 1-4 parts by weight of an epoxy resin powder coating comprising an inorganic filler 50-250 by weight parts Is disclosed. In the powder coating material of Patent Document 1, (1) the melt flowability is good, so that the core space is well filled, and (2) the powder coating material has good adhesion to the core and has good heat resistance. Because it is excellent, even if the heat generated during operation accumulates and the temperature of the rotor rises, the strong adhesive fixing force of the coil due to the cured resin can be maintained, and (3) the machinability of the cured resin is good, so the core surface It is described that the work of cutting and removing the excess cured resin of the above is easy.
However, it has been confirmed that the powder coating material of Patent Document 1 may cause initial cracks. Further, the powder coating material of Patent Document 1 has a limit in the heat resistance of the obtained cured product, and it is considered difficult to apply it to an armature having a higher temperature.
特許文献２には、（ａ）ノボラック型多官能エポキシ樹脂および（ｂ）ビスフェノールＡ型エポキシ樹脂からなるエポキシ樹脂（Ａ）、硬化剤（Ｂ）、無機充填材（Ｃ）、硬化促進剤（Ｄ）および応力緩和剤（Ｅ）を必須成分として含有するエポキシ樹脂系粉体塗料が開示されている。ここで、応力緩和剤（Ｅ）としては、各種ゴムが挙げられ、中でもシリコーンゴムが望ましいことが示されている。 Patent Document 2 describes an epoxy resin (A) composed of (a) novolak type polyfunctional epoxy resin and (b) bisphenol A type epoxy resin, a curing agent (B), an inorganic filler (C), and a curing accelerator (D). ) And the epoxy resin powder coating material containing the stress relieving agent (E) as essential components are disclosed. Here, examples of the stress relaxation agent (E) include various types of rubber, and it has been shown that silicone rubber is particularly desirable.
特許文献２の粉体塗料では、（ａ）ノボラック型多官能エポキシ樹脂の組成比を増加させることにより、耐熱性を向上させることが可能と考えられる。しかしながら、上記組成の粉体塗料では、（ａ）ノボラック型多官能エポキシ樹脂を増加させることにより、得られる硬化物の硬度が上昇し、初期クラックの発生が増加するという問題が生じる。
そこで、本発明は、初期クラックの発生が抑制され、かつ耐熱性に優れ、高温となる電機子への適用も可能な塗膜を製造するための粉体塗料を提供することを目的とする。
In the powder coating material of Patent Document 2, it is considered that the heat resistance can be improved by increasing the composition ratio of (a) the novolak type polyfunctional epoxy resin. However, in the powder coating material having the above composition, increasing the amount of (a) novolak type polyfunctional epoxy resin causes a problem that the hardness of the obtained cured product is increased and the occurrence of initial cracks is increased.
Therefore, an object of the present invention is to provide a powder coating material for producing a coating film which suppresses the occurrence of initial cracks, has excellent heat resistance, and can be applied to an armature having a high temperature.
上記課題に鑑み鋭意研究の結果、本発明者らは、ビスフェノールＡ型エポキシ樹脂、クレゾールノボラック型エポキシ樹脂、シリカ及びコアシェル粒子を含有する組成物を用いて、上記コアシェル粒子の種類や上記組成物の組成比等により、得られる粉体塗料の硬化物の線膨張係数及び機械衝撃強さ等を制御することにより上記課題を解決できることを見出し、本発明に想到した。すなわち、本発明の粉体塗料は、ビスフェノールＡ型エポキシ樹脂、クレゾールノボラック型エポキシ樹脂、シリカ及びコアシェル粒子を含有する組成物から得られる粉体塗料であって、上記コアシェル粒子のシェル層は、（メタ）アクリル酸エステルを含有し、上記粉体塗料の硬化物の５０℃〜９０℃における線膨張係数は、３５×１０−６／℃以下であり、上記粉体塗料を塗布後硬化して得られる４００μｍの塗膜の機械衝撃強さは、３０ｃｍ以上であることを特徴とする。
また、上記硬化物のガラス転移温度は１１５℃以上１４０℃以下であることが好ましい。
本発明の成形品は、上記粉体塗料を塗装した塗膜を備えることを特徴とする。
本発明の電機子は、上記粉体塗料を塗装した塗膜を備えることを特徴とする。
As a result of diligent research in view of the above problems, the present inventors have used a composition containing bisphenol A type epoxy resin, cresol novolac type epoxy resin, silica and core shell particles to select the types of the core shell particles and the above composition. We have found that the above problems can be solved by controlling the linear expansion coefficient, mechanical impact strength, etc. of the cured product of the obtained powder coating material by the composition ratio and the like, and have arrived at the present invention. That is, the powder coating material of the present invention is a powder coating material obtained from a composition containing a bisphenol A type epoxy resin, a cresol novolac type epoxy resin, silica and core shell particles, and the shell layer of the core shell particles is ( It contains a meta) acrylic acid ester, and the linear expansion coefficient of the cured product of the powder coating material at 50 ° C. to 90 ° C. is 35 × 10-6 / ° C. or less, and is obtained by applying the powder coating material and then curing it. The mechanical impact strength of the 400 μm coating film is 30 cm or more.
The glass transition temperature of the cured product is preferably 115 ° C. or higher and 140 ° C. or lower.
The molded product of the present invention is characterized by comprising a coating film coated with the above powder coating material.
The armature of the present invention is characterized by comprising a coating film coated with the above powder coating material.
本発明の粉体塗料では、初期クラックの発生が抑制され、かつ耐熱性に優れ、高温となる電機子への適用も可能な塗膜を得ることができる。 With the powder coating material of the present invention, it is possible to obtain a coating film in which the occurrence of initial cracks is suppressed, the heat resistance is excellent, and the coating film can be applied to an armature having a high temperature.
以下に本発明の実施の形態について詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail.
本発明の粉体塗料は、ビスフェノールＡ型エポキシ樹脂、クレゾールノボラック型エポキシ樹脂、シリカ及びコアシェル粒子を含有する樹脂組成物から得られる。
以下に、本発明の粉体塗料の詳細について説明する。
The powder coating material of the present invention is obtained from a resin composition containing a bisphenol A type epoxy resin, a cresol novolac type epoxy resin, silica and core-shell particles.
The details of the powder coating material of the present invention will be described below.
（１）ビスフェノールＡ型エポキシ樹脂
本発明の粉体塗料では、主剤として、ビスフェノールＡ型エポキシ樹脂を用いる。ビスフェノールＡ型エポキシ樹脂は、優れた接着性及び機械的強度、並びに適度な耐熱性を有する。
本発明で用いるビスフェノールＡ型エポキシ樹脂の分子量は、特に限定されないが、重量平均分子量が９００以上であることが好ましく、１２００以上であることがさらに好ましく、４４００以下であることが好ましく、２０００以下であることがさらに好ましい。ビスフェノールＡ型エポキシ樹脂の重量平均分子量を上記範囲内とすることにより、得られる粉体塗料の硬化物の柔軟性が向上し、初期クラックの発生がさらに有効に抑えられる。重量平均分子量は、ゲルパーミエーションクロマトグラフィ（ＧＰＣ）により、標準物質としてポリスチレンを用いて測定することができる。
本発明では、常温で液体状のビスフェノールＡ型エポキシ樹脂及び常温で固体状のビスフェノールＡ型エポキシ樹脂のいずれも用いることができる。常温で液体状のビスフェノールＡ型エポキシ樹脂の市販品としては、例えば、ｊＥＲ（登録商標）８２７、ｊＥＲ８２８、ｊＥＲ８２８ＥＬ、ｊＥＲ８２８ＸＡ、ｊＥＲ８３４（以上、三菱化学社製）、エポトート（登録商標）ＹＤ−１１５、エポトートＹＤ−１１５Ｇ、エポトートＹＤ−１１５ＣＡ、エポトートＹＤ−１１８Ｔ、エポトートＹＤ−１２７、エポトートＹＤ−１２８、エポトートＹＤ−１２８Ｇ、エポトートＹＤ−１２８Ｓ（以上、新日鉄住金化学社製）、ＥＰＩＣＬＯＮ（登録商標）８４０、ＥＰＩＣＬＯＮ８４０−Ｓ、ＥＰＩＣＬＯＮ８５０、ＥＰＩＣＬＯＮ８５０−Ｓ（以上、ＤＩＣ社製）等が挙げられる。
一方、常温で固体状のビスフェノールＡ型エポキシ樹脂の市販品としては、例えば、ｊＥＲ１００１、ｊＥＲ１００２、ｊＥＲ１００３、ｊＥＲ１００３Ｆ、ｊＥＲ１００４、ｊＥＲ１００４ＦＳ、ｊＥＲ１００４Ｆ、ｊＥＲ１００４ＡＦ、ｊＥＲ１０５５、ｊＥＲ１００５Ｆ、ｊＥＲ１００６ＦＳ、ｊＥＲ１００７、ｊＥＲ１００７ＦＳ、ｊＥＲ１００８、ｊＥＲ１００９（以上、三菱化学社製）、エポトートＹＤ−０１１、エポトートＹＤ−０１２、エポトートＹＤ−０１３、エポトートＹＤ−０１４、エポトートＹＤ−０１７、エポトートＹＤ−０１９、エポトートＹＤ−０２０Ｎ、エポトートＹＤ−０２０Ｈ（以上、新日鉄住金化学製）、ＥＰＩＣＬＯＮ１０５０、ＥＰＩＣＬＯＮ３０５０、ＥＰＩＣＬＯＮ４０５０、ＥＰＩＣＬＯＮ７０５０（以上、ＤＩＣ社製）、ＤＥＲ−６６１、ＤＥＲ−６６３Ｕ、ＤＥＲ−６６４、ＤＥＲ−６６７、ＤＥＲ−６６８、ＤＥＲ−６６９（以上、ダウケミカル社製）等が挙げられる。
(1) Bisphenol A type epoxy resin In the powder coating material of the present invention, a bisphenol A type epoxy resin is used as a main agent. The bisphenol A type epoxy resin has excellent adhesiveness, mechanical strength, and appropriate heat resistance.
The molecular weight of the bisphenol A type epoxy resin used in the present invention is not particularly limited, but the weight average molecular weight is preferably 900 or more, more preferably 1200 or more, preferably 4400 or less, and 2000 or less. It is more preferable to have. By setting the weight average molecular weight of the bisphenol A type epoxy resin within the above range, the flexibility of the cured product of the obtained powder coating material is improved, and the occurrence of initial cracks is more effectively suppressed. The weight average molecular weight can be measured by gel permeation chromatography (GPC) using polystyrene as a standard material.
In the present invention, both a bisphenol A type epoxy resin that is liquid at room temperature and a bisphenol A type epoxy resin that is solid at room temperature can be used. Commercially available products of bisphenol A type epoxy resin liquid at room temperature include, for example, jER (registered trademark) 827, jER828, jER828EL, jER828XA, jER834 (all manufactured by Mitsubishi Chemical Corporation), Epototo (registered trademark) YD-115, and the like. Epototo YD-115G, Epototo YD-115CA, Epototo YD-118T, Epototo YD-127, Epototo YD-128, Epototo YD-128G, Epototo YD-128S (all manufactured by Nippon Steel & Sumitomo Metal Corporation), EPICLON (registered trademark) 840 , EPICLON840-S, EPICLON850, EPICLON850-S (all manufactured by DIC) and the like.
On the other hand, as commercially available products of bisphenol A type epoxy resin which is solid at room temperature, for example, jER1001, jER1002, jER1003, jER1003F, jER1004, jER1004FS, jER1004F, jER1004AF, jER1055, jER1005F, jER1006FS, jER1007, jER1007FS, jER1007, jER1007FS (Made by Mitsubishi Chemical Co., Ltd.), Epototo YD-011, Epototo YD-012, Epototo YD-013, Epototo YD-014, Epototo YD-017, Epototo YD-019, Epototo YD-020N, Epototo YD-020H Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), EPICLON1050, EPICLON3050, EPICLON4050, EPICLON7050 (above, DIC), DER-661, DER-663U, DER-664, DER-667, DER-668, DER-669 (above, Dow Chemical) Made) and the like.
（２）クレゾールノボラック型エポキシ樹脂
本発明では、エポキシ樹脂として、ビスフェノールＡ型エポキシ樹脂とともにクレゾールノボラック型エポキシ樹脂を用いる。クレゾールノボラック型エポキシ樹脂を用いることにより、粉体塗料から得られる硬化物のガラス転移温度が上昇して、耐熱性が向上する。このため、高温になる電機子用に用いた場合でも優れたコイル固着効果を維持することができる。
本発明で用いるクレゾールノボラック型エポキシ樹脂の物性は、特に限定されないが、軟化点が６０℃以上であることが好ましく、６８℃以上であることがさらに好ましく、１１０℃以下であることが好ましく、１００℃以下であることがさらに好ましい。クレゾールノボラック型エポキシ樹脂の軟化点を上記範囲内とすることにより、より高ガラス転移温度化が可能となる。軟化点は、ＪＩＳ Ｋ ７２３４の環球法で測定することができる。
また、本発明で用いるクレゾールノボラック型エポキシ樹脂のエポキシ当量も特に限定されないが、２００ｇ／ｅｑ以上であることが好ましく、２４０ｇ／ｅｑ以下であることが好ましい。クレゾールノボラック型エポキシ樹脂のエポキシ当量を上記範囲内とすることにより、より優れた効果が得られる。
本発明の粉体塗料のビスフェノールＡ型エポキシ樹脂とクレゾールノボラック型エポキシ樹脂の組成比は、使用する前記ビスフェノールＡ型エポキシ樹脂及びクレゾールノボラック型エポキシ樹脂の分子量等にもよるが、総質量を１００としたとき、クレゾールノボラック型エポキシ樹脂の含有量は、１５質量％〜４０質量％であることが好ましく、２０質量％〜３５質量％であることがより好ましい。ビスフェノールＡ型エポキシ樹脂とクレゾールノボラック型エポキシ樹脂の組成比を上記範囲とすることにより、より優れた耐熱性及び耐衝撃性を有する塗膜硬化物を得ることができる。
本発明では、市販のクレゾールノボラック型エポキシ樹脂を用いることもできる。市販品としては、例えば、エポトートＹＤＣＮ−７０１（エポキシ当量１９５〜２２０ｇ／ｅｑ、軟化点約６０〜７０℃、新日鉄住金化学社製）、エポトートＹＤＣＮ−７０２（エポキシ当量１９５〜２２０ｇ／ｅｑ、軟化点約７０〜８０℃、新日鉄住金化学社製）、エポトートＹＤＣＮ−７０３（エポキシ当量１９５〜２２０ｇ／ｅｑ、軟化点約７５〜８５℃、新日鉄住金化学社製）、エポトートＹＤＣＮ−７０４（エポキシ当量１９５〜２２０ｇ／ｅｑ、軟化点約８５〜９５℃、新日鉄住金化学社製）、エピコート１８０Ｓ６５（エポキシ当量２０５〜２２０ｇ／ｅｑ、軟化点約６７℃、三菱化学社製）等が挙げられる。これらは単独で使用することもできるが、２種類以上を併用することもできる。
なお、本発明の効果を阻害しない範囲で、粉体塗料組成物には、（１）ビスフェノールＡ型エポキシ樹脂と（２）クレゾールノボラック型エポキシ樹脂以外のエポキシ樹脂を添加することもできる。
(2) Cresol Novolac Epoxy Resin In the present invention, a cresol novolac type epoxy resin is used together with a bisphenol A type epoxy resin as the epoxy resin. By using the cresol novolac type epoxy resin, the glass transition temperature of the cured product obtained from the powder coating material rises, and the heat resistance is improved. Therefore, an excellent coil fixing effect can be maintained even when used for an armature that becomes hot.
The physical properties of the cresol novolac type epoxy resin used in the present invention are not particularly limited, but the softening point is preferably 60 ° C. or higher, more preferably 68 ° C. or higher, preferably 110 ° C. or lower, 100. It is more preferably ° C. or lower. By setting the softening point of the cresol novolac type epoxy resin within the above range, a higher glass transition temperature can be achieved. The softening point can be measured by the ring ball method of JIS K 7234.
The epoxy equivalent of the cresol novolac type epoxy resin used in the present invention is also not particularly limited, but is preferably 200 g / eq or more, and preferably 240 g / eq or less. By setting the epoxy equivalent of the cresol novolac type epoxy resin within the above range, a more excellent effect can be obtained.
The composition ratio of the bisphenol A type epoxy resin and the cresol novolac type epoxy resin of the powder coating of the present invention depends on the molecular weight and the like of the bisphenol A type epoxy resin and the cresol novolac type epoxy resin used, but the total mass is 100. The content of the cresol novolac type epoxy resin is preferably 15% by mass to 40% by mass, more preferably 20% by mass to 35% by mass. By setting the composition ratio of the bisphenol A type epoxy resin and the cresol novolac type epoxy resin within the above range, a cured coating film having more excellent heat resistance and impact resistance can be obtained.
In the present invention, a commercially available cresol novolac type epoxy resin can also be used. Commercially available products include, for example, Epototo YDCN-701 (epoxy equivalent 195 to 220 g / eq, softening point about 60 to 70 ° C., manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), Epototo YDCN-702 (epoxy equivalent 195 to 220 g / eq, softening point). Approximately 70-80 ° C, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., Epototo YDCN-703 (epoxy equivalent 195-220 g / eq, softening point approximately 75-85 ° C, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), Epototo YDCN-704 (epoxy equivalent 195- 220 g / eq, softening point about 85-95 ° C., manufactured by Nippon Steel & Sumitomo Metal Corporation), Epicoat 180S65 (epoxy equivalent 205-220 g / eq, softening point about 67 ° C., manufactured by Mitsubishi Chemical Co., Ltd.) and the like. These can be used alone, but two or more types can be used in combination.
An epoxy resin other than (1) bisphenol A type epoxy resin and (2) cresol novolac type epoxy resin can be added to the powder coating composition as long as the effects of the present invention are not impaired.
（３）シリカ
本発明の粉体塗料は、充填剤としてシリカを含有する組成物から製造される。充填剤としてシリカを用いることにより、得られる樹脂塗膜硬化物の強度が向上するため、初期クラックの発生を有効に抑えることができる。シリカの種類は、特に限定されず、例えば、結晶性シリカ、溶融シリカ、合成シリカ等が挙げられる。シリカ粒子の形状も特に限定されず、球状、針状、又は不定形形状等のシリカを用いることができる。シリカ粒子の平均粒径は、１０μｍ〜５０μｍが好ましく、２０μｍ〜４０μｍがより好ましい。シリカ粒子の平均粒径が１０μｍ未満であるとシリカ粒子が凝集しやすくなる。また、組成物の溶融粘度も上昇しやすく、作業性が低下するため、組成物中に十分なシリカを均一に添加することが困難となる。このため、粉体塗料から得られる塗膜硬化物の線膨張係数を効果的に低減することは難しく、塗膜硬化物とコイルやコアとの界面で剥離が生じる可能性がある。一方、シリカ粒子の平均粒径が５０μｍを超えると、塗装性が悪くなる可能性がある。なお、表面をカップリング剤で表面処理したシリカを用いることもできる。
シリカ粒子の含有量は、求められる塗膜硬化物の線膨張係数や機械衝撃強さ等の物性に応じて、適宜調整することができる。通常、シリカ粒子の含有量は、粉体塗料全体に対して、３５質量％〜７５質量％が好ましく、４５質量％〜７０質量％がより好ましい。シリカ粒子の含有量を上記範囲とすることにより、作業性に優れ、塗膜硬化物の線膨張係数を十分低下させることができるため、塗膜硬化物の初期クラックの発生や塗膜硬化物とコイルやコアとの界面での剥離をより効果的に抑制することができる。
(3) Silica The powder coating material of the present invention is produced from a composition containing silica as a filler. By using silica as the filler, the strength of the obtained cured resin coating film is improved, so that the occurrence of initial cracks can be effectively suppressed. The type of silica is not particularly limited, and examples thereof include crystalline silica, fused silica, and synthetic silica. The shape of the silica particles is not particularly limited, and silica having a spherical shape, a needle shape, an amorphous shape, or the like can be used. The average particle size of the silica particles is preferably 10 μm to 50 μm, more preferably 20 μm to 40 μm. If the average particle size of the silica particles is less than 10 μm, the silica particles tend to aggregate. In addition, the melt viscosity of the composition tends to increase and the workability decreases, so that it becomes difficult to uniformly add sufficient silica to the composition. Therefore, it is difficult to effectively reduce the coefficient of linear expansion of the cured coating film obtained from the powder coating material, and peeling may occur at the interface between the cured coating film and the coil or core. On the other hand, if the average particle size of the silica particles exceeds 50 μm, the coatability may deteriorate. In addition, silica whose surface is surface-treated with a coupling agent can also be used.
The content of silica particles can be appropriately adjusted according to the required physical properties such as the coefficient of linear expansion of the cured coating film and the mechanical impact strength. Generally, the content of silica particles is preferably 35% by mass to 75% by mass, more preferably 45% by mass to 70% by mass, based on the entire powder coating material. By setting the content of the silica particles in the above range, the workability is excellent and the coefficient of linear expansion of the cured coating film can be sufficiently lowered. Peeling at the interface with the coil or core can be suppressed more effectively.
（４）コアシェル粒子
本発明の粉体塗料は、（メタ）アクリル酸エステルを含有するシェル層を有するコアシェル粒子を含有する組成物から得られる。コアシェル粒子とは、コア部の表面にシェル層を有する２又は３以上の層をもつ粒子である。通常、コア部は、低ガラス転移温度のアクリル樹脂やブタジエン、イソプレン等のジエン系重合体からなる。また、シェル層は、ポリメチルメタアクリレート，ポリスチレン，アクリロニトリル−スチレン共重合体，メチルメタアクリレート−スチレン共重合体のようなＴｇの高いガラス質の高分子からなる。本発明では、コア部の成分は特に限定されないが、シェル層は、（メタ）アクリル酸エステルを含有することを特徴とする。シェル層が（メタ）アクリル酸エステルを含有することにより、粉体塗料から得られる硬化物の熱衝撃緩和特性が顕著に向上することが確認された。これは、シェル層である（メタ）アクリル酸エステルがエポキシ樹脂及びシリカの双方と親和性が高いためと考えられる。
コアシェル粒子の含有量は、粉体塗料全体に対して、１〜５質量％であることが好ましく、１〜３質量％であることがより好ましい。コアシェル粒子の含有量を上記範囲とすることにより、溶融混合においてコアシェル分子が良好に分散及び混合するため、より均一性の高い塗膜硬化物を得ることができる。
コアシェル粒子の製造方法は特に限定されないが、例えば、多段シード乳化重合法等により、初めに、コア層粒子を重合し、コア層上にシェル層を重合することにより製造される。コア部の高分子の分子量を最適化することにより、コアシェル粒子の熱衝撃緩和効果がさらに向上するため、得られる粉体塗料硬化物の初期クラックの発生がより有効に抑えられる。また、本発明で用いることのできるコアシェルの市販品としては、ブタジエン・メタクリル酸アルキル・スチレン共重合体からなるパラロイドＥＸＬ−２６５５（Ｒｏｈｍ＆Ｈａａｓ社製）、アクリル酸エステル・メタクリル酸エステル共重合体からなるパラロイドＥＸＬ−２３１４（Ｒｏｈｍ＆Ｈａａｓ社製）、スタフィロイドＡＣ−３３５５、スタフィロイドＴＲ−２１２２（武田薬品工業社製）、パラロイドＥＸＬ−２６１１、ＥＸＬ−３３８７（登録商標、Ｒｏｈｍ＆Ｈａａｓ社製）等を使用することができる。
(4) Core-shell particles The powder coating material of the present invention is obtained from a composition containing core-shell particles having a shell layer containing (meth) acrylic acid ester. The core-shell particles are particles having two or three or more layers having a shell layer on the surface of the core portion. Usually, the core portion is made of an acrylic resin having a low glass transition temperature or a diene polymer such as butadiene or isoprene. The shell layer is made of a vitreous polymer having a high Tg such as polymethylmethacrylate, polystyrene, acrylonitrile-styrene copolymer, and methylmethacrylate-styrene copolymer. In the present invention, the component of the core portion is not particularly limited, but the shell layer is characterized by containing a (meth) acrylic acid ester. It was confirmed that the thermal shock mitigation property of the cured product obtained from the powder coating material was remarkably improved when the shell layer contained the (meth) acrylic acid ester. It is considered that this is because the (meth) acrylic acid ester, which is the shell layer, has a high affinity with both the epoxy resin and silica.
The content of the core-shell particles is preferably 1 to 5% by mass, more preferably 1 to 3% by mass, based on the entire powder coating material. By setting the content of the core-shell particles in the above range, the core-shell molecules are satisfactorily dispersed and mixed in the melt mixing, so that a more uniform cured coating film can be obtained.
The method for producing the core-shell particles is not particularly limited, but for example, the core-shell particles are produced by first polymerizing the core layer particles and then polymerizing the shell layer on the core layer by a multi-stage seed emulsion polymerization method or the like. By optimizing the molecular weight of the polymer in the core portion, the thermal shock mitigation effect of the core-shell particles is further improved, so that the occurrence of initial cracks in the obtained cured powder coating material can be more effectively suppressed. Commercially available core shell products that can be used in the present invention include paraloid EXL-2655 (manufactured by Rohm & Haas) made of a butadiene / alkyl methacrylate / styrene copolymer and an acrylic acid ester / methacrylic acid ester copolymer. Use Pararoid EXL-2314 (manufactured by Rohm & Haas), Staphyroid AC-3355, Staphyroid TR-2122 (manufactured by Takeda Pharmaceutical Company Limited), Pararoid EXL-2611, EXL-3387 (registered trademark, manufactured by Rohm & Haas), etc. Can be done.
（５）硬化剤
本発明の粉体塗料用の組成物は、硬化剤を含有することが好ましい。具体的な硬化剤としては、ジシアンジアミド；４，４’−ジアミノジフェニルメタン、４，４’−ジアミノジフェニルスルホン、３，３’−ジアミノジフェニルスルホン、ｍ−フェニレンジアミン、ｍ−キシリレンジアミン等の活性水素を有する芳香族アミン；ジエチレントリアミン、トリエチレンテトラミン、イソホロンジアミン、ビス（アミノメチル）ノルボルナン、ビス（４−アミノシクロヘキシル）メタン、ポリエチレンイミンのダイマー酸エステル等の活性水素を有する脂肪族アミン；これらの活性水素を有するアミンにエポキシ化合物、アクリロニトリル、フェノールとホルムアルデヒド、チオ尿素等の化合物を反応させて得られる変性アミン；ジメチルアニリン、トリエチレンジアミン、ジメチルベンジルアミン、２，４，６−トリス（ジメチルアミノメチル）フェノール等の活性水素を持たない第三アミン；２−メチルイミダゾール、２−エチル−４−メチルイミダゾールなどのイミダゾール類；ポリアミド樹脂；ヘキサヒドロフタル酸無水物、テトラヒドロフタル酸無水物、メチルヘキサヒドロフタル酸無水物、メチルナジック酸無水物等のカルボン酸無水物；アジピン酸ヒドラジドやナフタレンジカルボン酸ヒドラジド等のポリカルボン酸ヒドラジド；ノボラック樹脂等のポリフェノール化合物；チオグリコール酸とポリオールのエステル等のポリメルカプタン；及び、三フッ化ホウ素エチルアミン錯体等のルイス酸錯体等を用いることができる。これらの硬化剤の中でも、ジシアンジアミド、芳香族アミン類を用いることが好ましい。
(5) Curing Agent The composition for powder coating material of the present invention preferably contains a curing agent. Specific curing agents include active hydrogens such as dicyandiamide; 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, m-phenylenediamine, m-xylylene diamine and the like. Aromatic amines with active hydrogens such as diethylenetriamine, triethylenetetramine, isophoronediamine, bis (aminomethyl) norbornan, bis (4-aminocyclohexyl) methane, dimer acid esters of polyethyleneimine; these activities Modified amines obtained by reacting amines with hydrogen with compounds such as epoxy compounds, acrylonitrile, phenols with formaldehyde, thiourea; dimethylaniline, triethylenediamine, dimethylbenzylamine, 2,4,6-tris (dimethylaminomethyl) Tertiary amines without active hydrogen such as phenol; imidazoles such as 2-methylimidazole and 2-ethyl-4-methylimidazole; polyamide resin; hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthal Caroxyan anhydrides such as acid anhydrides and methylnadic acid anhydrides; Polycarboxylic acid hydrazides such as adipic acid hydrazide and naphthalenedicarboxylic acid hydrazide; Polyphenol compounds such as novolak resin; Polymercaptans such as esters of thioglycolic acid and polyol; And a Lewis acid complex such as a boron trifluoride ethylamine complex can be used. Among these curing agents, it is preferable to use dicyandiamide and aromatic amines.
（６）添加剤
本発明の粉体塗料には、発明の効果が損なわれない範囲で、必要に応じて各種添加剤を添加することができる。上記添加剤としては、シリカ以外の充填剤、レベリング剤、着色剤、カップリング剤、硬化促進剤、消泡剤、密着向上剤等が挙げられる。シリカ以外の充填剤としては、例えば、炭酸カルシウム、ケイ酸カルシウム、アルミナ、マイカ等が挙げられる。
(6) Additives Various additives can be added to the powder coating material of the present invention as needed, as long as the effects of the present invention are not impaired. Examples of the additive include fillers other than silica, leveling agents, colorants, coupling agents, curing accelerators, defoamers, adhesion improvers and the like. Examples of the filler other than silica include calcium carbonate, calcium silicate, alumina, mica and the like.
（７）粉体塗料の製造方法
本発明の粉体塗料の製造方法は特に限定されないが、例えば以下の方法により製造することができる。初めに、ミキサー等により配合成分を乾式混合した後、エクストルーダを用いて溶融混合等を行う。混合温度や混合時間は、特に限定されず、原料の種類や組成比等に応じて設定される。通常、混合温度は、１００℃〜１５０℃が好ましく、１０５℃〜１２０℃がより好ましい。
その後、得られた混合物を冷却固化し、固化した混合物を微粉砕して、分級することにより粉体塗料が得られる。
(7) Method for producing powder coating material The method for producing powder coating material of the present invention is not particularly limited, but can be produced by, for example, the following method. First, the ingredients are dry-mixed with a mixer or the like, and then melt-mixed or the like with an extruder. The mixing temperature and mixing time are not particularly limited, and are set according to the type of raw material, composition ratio, and the like. Usually, the mixing temperature is preferably 100 ° C. to 150 ° C., more preferably 105 ° C. to 120 ° C.
Then, the obtained mixture is cooled and solidified, and the solidified mixture is finely pulverized and classified to obtain a powder coating material.
（８）粉体塗料
本発明の粉末塗料は、ビスフェノールＡ型エポキシ樹脂及びクレゾールノボラック型エポキシ樹脂を含有する。混合条件によっては、一部重合が進行し、ビスフェノールＡ型エポキシ樹脂に由来する構造単位及びクレゾールノボラック型エポキシ樹脂に由来する構造単位を含む重合体を含有する。
本発明の粉体塗料の粒子径は、特に限定されないが、レーザー回折・散乱法（ＪＩＳ Ｚ８８２５）による体積平均粒子径が３０μｍ〜７０μｍの範囲であることが好ましい。なお、上記体積平均粒子径は、レーザー回折式粒子径分布測定装置（SYMPATEC社製、HELOS and PRODOS 解析ソフト：WINDOX5）を用いて測定することができる。
体積平均粒子径が上記範囲の粉体塗料を用いることにより、より優れた成膜性が得られる。
(8) Powder coating The powder coating of the present invention contains a bisphenol A type epoxy resin and a cresol novolac type epoxy resin. Depending on the mixing conditions, partial polymerization proceeds, and a polymer containing a structural unit derived from a bisphenol A type epoxy resin and a structural unit derived from a cresol novolac type epoxy resin is contained.
The particle size of the powder coating material of the present invention is not particularly limited, but it is preferable that the volume average particle size by the laser diffraction / scattering method (JIS Z8825) is in the range of 30 μm to 70 μm. The volume average particle size can be measured using a laser diffraction type particle size distribution measuring device (HELOS and PRODOS analysis software: WINDOX5 manufactured by SYMPATEC).
By using a powder coating having a volume average particle diameter in the above range, better film forming property can be obtained.
また、本発明の粉体塗料の傾斜流れ度は、０．５〜５の範囲であることが好ましい。一般に傾斜流れ度が大きい粉体塗料は、溶融時に低粘度で塗料が流れやすく、一方、傾斜流れ度が小さい粉体塗料は、溶融時に高粘度で塗料が流れにくい。粉体塗料の傾斜流れ度を上記範囲にすることにより、ピンホール等の塗膜欠陥やタレが生じにくく、目的とする膜厚の良質な塗膜が得られやすい。粉体塗料の傾斜流れ度は、１〜３であることがより好ましい。
なお、傾斜流れ度は以下の方法により算出される。粉体塗料０．５ｇを内径１３ｍｍφの錠剤成形用金型に入れ、荷重１６ＭＰａで６０秒加圧して得られる錠剤の直径（ａ）及び厚み（ｂ）をノギスで測定する。上記錠剤をスライドガラスに載せ、熱風乾燥機中にて１５０℃で２０分間加熱後、同様に錠剤の直径（ｃ）を測定する。加熱による直径の増加値（ｃ−ａ）を加熱前の厚み（ｂ）で除した値とする。
Further, the gradient flow rate of the powder coating material of the present invention is preferably in the range of 0.5 to 5. In general, a powder coating material having a large gradient flow rate has a low viscosity at the time of melting and the coating material easily flows, while a powder coating material having a small inclination flow rate has a high viscosity when melting and the coating material does not easily flow. By setting the gradient flow rate of the powder coating material within the above range, coating film defects such as pinholes and sagging are less likely to occur, and a high-quality coating film having a desired film thickness can be easily obtained. The gradient flow rate of the powder coating material is more preferably 1 to 3.
The gradient flow rate is calculated by the following method. 0.5 g of powder coating material is placed in a tablet molding die having an inner diameter of 13 mmφ, and the tablet diameter (a) and thickness (b) obtained by pressurizing with a load of 16 MPa for 60 seconds are measured with a caliper. The tablet is placed on a slide glass, heated in a hot air dryer at 150 ° C. for 20 minutes, and then the tablet diameter (c) is measured in the same manner. It is defined as the value obtained by dividing the increase value (ca) of the diameter due to heating by the thickness (b) before heating.
（９）粉体塗料の塗装方法
本発明の粉体塗料の塗装方法は、特に限定されず、公知の塗装方法が適用できる。具体的には、静電塗装、摩擦帯電塗装、無荷電塗装、流動浸漬等が挙げられる。上記方法により、被塗装体表面に粉体塗料を塗装した後、硬化することにより塗膜を得ることができる。必要に応じて被塗装体に予め表面処理を施すことにより、塗膜の密着性等を向上させることもできる。
以下に本発明の粉体塗料を用いて、巻成されたコイルを電機子のコア空間内に固定する方法の一例を示す。
予めコイルを含む電機子コア全体を粉体塗料の溶融温度以上に加熱しておく。コイル面を含む電機子表面及びコア空間内に上記の粉体塗装方法により本発明の粉体塗料を塗装する。これにより、コア表面に付着した粉体塗料は、コア表面上で溶融する。続いて、電機子コアをさらに加熱することにより、溶融物を完全に硬化させる。その後、コア空間部以外のコア表面上に固着している余分の硬化物をナイフ刃又はバイト刃等により切削除去する。
本発明の粉体塗料から得られる塗膜の膜厚は特に限定されないが、５０μｍ以上５００μｍ以下であることが好ましい。
(9) Coating method of powder coating The coating method of the powder coating of the present invention is not particularly limited, and a known coating method can be applied. Specific examples thereof include electrostatic coating, triboelectric coating, non-charged coating, and fluid immersion. By the above method, a coating film can be obtained by applying a powder coating material to the surface of an object to be coated and then curing the powder coating material. If necessary, the surface treatment of the object to be coated is applied in advance to improve the adhesion of the coating film and the like.
An example of a method of fixing the wound coil in the core space of the armature using the powder coating material of the present invention is shown below.
The entire armature core including the coil is preheated to a temperature equal to or higher than the melting temperature of the powder coating material. The powder coating material of the present invention is applied to the armature surface including the coil surface and the core space by the above powder coating method. As a result, the powder coating material adhering to the core surface melts on the core surface. Subsequently, the armature core is further heated to completely cure the melt. After that, the excess cured product adhering to the core surface other than the core space is cut and removed with a knife blade, a tool blade, or the like.
The film thickness of the coating film obtained from the powder coating material of the present invention is not particularly limited, but is preferably 50 μm or more and 500 μm or less.
（１０）粉体塗料の塗膜硬化物
（ｉ）線膨張係数
本発明では、粉体塗料の硬化物の５０℃〜９０℃における線膨張係数が３５×１０-６／℃以下となるように調整する。上記線膨張係数は、ＪＩＳ Ｃ２１６１に基づいて、熱機械分析装置（ＴＭＡ）を用いて測定を行い、算出する。具体的には、荷重１０ｇ、昇温速度５℃／ｍｉｎで、０℃〜２５０℃の温度範囲で測定を行い、試料の寸法変位から線膨張係数を算出する。線膨張係数測定用の試料は、得られた粉体塗料を用いて、５ｍｍ×５ｍｍ×２０ｍｍの角柱に成形して試験片を作製し、１８０℃で２０分硬化することにより調製する。
粉体塗料の硬化物の５０℃〜９０℃における線膨張係数が３５×１０-６／℃を超える場合は、良好な耐初期クラック特性が得られず、高温になる電機子に用いた場合、コイルやコアとの剥離が生じやすい。上記線膨張係数は、３０×１０-６／℃以下であることがより好ましい。
粉体塗料の硬化物の線膨張係数を上記範囲とすることにより、塗膜硬化物の初期クラックの発生が抑えられ、高温になる電機子に用いた場合でも塗膜硬化物とコイルやコアとの剥離が効果的に抑制され、優れた固着効果を発揮することができる。
(10) Cured coating film of powder coating (i) Coefficient of linear expansion In the present invention, the coefficient of linear expansion of the cured product of powder coating at 50 ° C to 90 ° C is 35 × 10 -6 / ° C or less. adjust. The coefficient of linear expansion is measured and calculated using a thermomechanical analyzer (TMA) based on JIS C2161. Specifically, the measurement is performed in a temperature range of 0 ° C. to 250 ° C. with a load of 10 g and a heating rate of 5 ° C./min, and the coefficient of linear expansion is calculated from the dimensional displacement of the sample. A sample for measuring the coefficient of linear expansion is prepared by forming a test piece into a prism of 5 mm × 5 mm × 20 mm using the obtained powder coating material and curing it at 180 ° C. for 20 minutes.
If the coefficient of linear expansion of the cured product of the powder coating exceeds 35 × 10 -6 / ° C, good initial crack resistance cannot be obtained, and when used for an armature that becomes hot, Peeling from the coil and core is likely to occur. The coefficient of linear expansion is more preferably 30 × 10 -6 / ° C. or lower.
By setting the coefficient of linear expansion of the cured product of the powder coating within the above range, the occurrence of initial cracks in the cured coating film is suppressed, and even when used in an armature that becomes hot, the cured coating film and the coil or core Peeling is effectively suppressed, and an excellent fixing effect can be exhibited.
（ｉｉ）機械衝撃強さ
また、本発明では、粉体塗料を塗布後硬化して得られる４００μｍの塗膜の機械衝撃強さが、３０ｃｍ以上となるように調整する。上記塗膜の機械衝撃強さは、ＪＩＳ Ｃ２１６１に基づいて測定する。具体的には、荷重５００ｇのおもりを用いて、撃芯半径１／８インチで衝撃試験を実施する。
粉体塗料を塗布後硬化して得られる４００μｍの塗膜の機械衝撃強さが、３０ｃｍ未満では、良好な耐初期クラック特性を得ることができない。上記機械衝撃強さは、４０ｃｍ以上であることがより好ましい。
粉体塗料の硬化物の機械衝撃強さを上記範囲とすることにより、塗膜硬化物の初期クラックの発生を効果的に抑制することができる。
(Ii) Mechanical Impact Strength In the present invention, the mechanical impact strength of a 400 μm coating film obtained by applying and curing a powder coating film is adjusted to be 30 cm or more. The mechanical impact strength of the coating film is measured based on JIS C2161. Specifically, an impact test is carried out using a weight with a load of 500 g and a striking core radius of 1/8 inch.
If the mechanical impact strength of the 400 μm coating film obtained by applying the powder coating and then curing is less than 30 cm, good initial crack resistance cannot be obtained. The mechanical impact strength is more preferably 40 cm or more.
By setting the mechanical impact strength of the cured product of the powder coating within the above range, the occurrence of initial cracks in the cured coating film can be effectively suppressed.
（ｉｉｉ）ガラス転移温度（Ｔｇ）
本発明では、粉体塗料の硬化物のガラス転移温度が１１５℃以上１４０℃以下となるように調整する。上記ガラス転移温度は、ＪＩＳ Ｃ２１６１に基づいて、熱機械分析装置（ＴＭＡ）を用いて測定を行い、算出する。具体的には、荷重１０ｇ、昇温速度５℃／ｍｉｎで、０〜２５０℃の温度範囲で測定を行う。Ｔｇ測定用の試料は、得られた粉体塗料を用いて、５ｍｍ×５ｍｍ×２０ｍｍの角柱に成形して試験片を作製し、１８０℃で２０分硬化することにより調製する。
粉体塗料の硬化物のガラス転移温度が、１１５℃未満では、高負荷で高温になる電機子での使用において、塗膜硬化物を安定して維持することが難しい場合がある。一方、粉体塗料の硬化物のガラス転移温度が、１４０℃を超えると、樹脂の脆さに起因する機械衝撃強さの低下が問題になることがある。
粉体塗料の硬化物のガラス転移温度は、１２０℃以上１３０℃以下であることがより好ましい。
粉体塗料の硬化物のガラス転移温度を上記範囲とすることにより、高負荷で高温になる電機子に使用した場合でも塗膜硬化物が安定して維持され、優れたコイルの固着効果が実現される。
(Iii) Glass transition temperature (Tg)
In the present invention, the glass transition temperature of the cured product of the powder coating material is adjusted to be 115 ° C. or higher and 140 ° C. or lower. The glass transition temperature is measured and calculated using a thermomechanical analyzer (TMA) based on JIS C2161. Specifically, the measurement is performed in a temperature range of 0 to 250 ° C. with a load of 10 g and a heating rate of 5 ° C./min. The sample for Tg measurement is prepared by forming a test piece into a prism of 5 mm × 5 mm × 20 mm using the obtained powder coating material and curing it at 180 ° C. for 20 minutes.
If the glass transition temperature of the cured product of the powder coating film is less than 115 ° C., it may be difficult to stably maintain the cured coating film when used in an armature that becomes hot under a high load. On the other hand, if the glass transition temperature of the cured product of the powder coating material exceeds 140 ° C., a decrease in mechanical impact strength due to the brittleness of the resin may become a problem.
The glass transition temperature of the cured product of the powder coating material is more preferably 120 ° C. or higher and 130 ° C. or lower.
By setting the glass transition temperature of the cured product of the powder coating within the above range, the cured coating film is stably maintained even when used in an armature that becomes hot under a high load, and an excellent coil fixing effect is realized. Will be done.
以下の実施例により本発明をさらに詳細に説明するが、本発明はこれら実施例によって限定されるものではない。なお、実施例中、特に記載がない場合には、「％」及び「部」は質量％及び質量部を示す。 The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the examples, unless otherwise specified, "%" and "part" indicate mass% and parts by mass.
〈粉体塗料の構成成分〉
（Ａ）ビスフェノールＡ型エポキシ樹脂
（Ａ１）ｊＥＲ１００２ 三菱化学株式会社製
（Ａ２）ｊＥＲ１００４ 三菱化学株式会社製
（Ｂ）クレゾールノボラック型エポキシ樹脂
（Ｂ１）ＥＰＩＣＬＯＮ Ｎ―６８０ ＤＩＣ株式会社製
（Ｂ２）ＥＰＩＣＬＯＮ Ｎ―６９５ ＤＩＣ株式会社製
（Ｃ）硬化剤 ジシアンジアミド ｊＥＲキュアＤＩＣＹ２０ 三菱化学株式会社製
（Ｄ）硬化促進剤 ２，４−ジアミノ−６−［２’−メチルイミダゾリル− （１’）］−エチル−ｓ−トリアジン キュアゾール２ＭＺ−Ａ 四国化成工業株式会社製
（Ｅ）充填剤
（Ｅ１）シリカ：球状溶融シリカ Ｓ−２６Ｃ 新日鉄住金マテリアルズ株式会社製
（Ｅ２）炭酸カルシウム：ソフトン１２００ 備北粉化工業株式会社製
（Ｆ）衝撃緩和剤
（Ｆ１）コアシェル粒子 パラロイドＥＸＬ−２３１４ Ｒｏｈｍ＆Ｈａａｓ社製
（Ｆ２）シリコーン粒子 トレフィルＥ−６００ ダウ・コーニング社製
<Components of powder paint>
(A) Bisphenol A type epoxy resin (A1) jER1002 Made by Mitsubishi Chemical Corporation (A2) jER1004 Made by Mitsubishi Chemical Co., Ltd. (B) Cresol Novorak type epoxy resin (B1) EPICLON N-680 DIC Corporation (B2) EPICLON N -695 DIC Corporation (C) Curing Agent Dicyandiamide jER Cure DICY20 Mitsubishi Chemical Corporation (D) Curing Accelerator 2,4-diamino-6- [2'-Methylimidazolyl- (1')]-Eethyl-s -Triazine Curesol 2MZ-A Shikoku Kasei Kogyo Co., Ltd. (E) Filler (E1) Silica: Spherical molten silica S-26C Nippon Steel & Sumikin Materials Co., Ltd. (E2) Calcium carbonate: Softon 1200 Bihoku Powder Industry Co., Ltd. (F) Impact reducer (F1) Core shell particles Paraloid EXL-2314 Rohm & Haas (F2) Silicone particles Trefil E-600 Dow Corning
（実施例１〜２、比較例１〜７）
表１に示す配合比（質量）でビスフェノールＡ型エポキシ樹脂、クレゾールノボラック型エポキシ樹脂、硬化剤、硬化促進剤、充填剤及び衝撃緩和剤をミキサーで混合後、エクストルーダにより溶融混合した。ここで、混合温度は、１１０〜１２０℃、混合時間は、３０秒以下とした。混合物を冷却固化した後、微粉砕することにより、各実施例及び比較例の粉体塗料を得た。前述する方法で粉体塗料の硬化物の線膨張係数、機械衝撃強さ及びガラス転移温度を測定した結果を、表１に示す。また、後述する方法で、耐初期クラック（熱衝撃）性評価及び耐ヒートサイクル性評価を行った結果も表１に示す。
(Examples 1 and 2, Comparative Examples 1 to 7)
Bisphenol A type epoxy resin, cresol novolac type epoxy resin, curing agent, curing accelerator, filler and impact mitigating agent were mixed with a mixer at the blending ratio (mass) shown in Table 1, and then melt-mixed with an extruder. Here, the mixing temperature was 110 to 120 ° C., and the mixing time was 30 seconds or less. The mixture was cooled and solidified, and then finely pulverized to obtain powder coating materials of Examples and Comparative Examples. Table 1 shows the results of measuring the linear expansion coefficient, mechanical impact strength, and glass transition temperature of the cured product of the powder coating by the method described above. Table 1 also shows the results of initial crack resistance (thermal shock) resistance evaluation and heat cycle resistance evaluation by the method described later.
（耐初期クラック性評価）
実施例及び比較例の粉体塗料をナット、外歯付座金、六角ボルトを用いて作製した模擬ワークを送風乾燥炉内で、１８０℃で２０分予熱後、８秒間流動浸漬してから、１８０℃で１分間加熱して硬化させた。硬化後、５分間水冷し、表面の水分を取り除き、一晩放置し、クラックの有無を目視で確認した。各実施例及び比較例について、２つ試料を作製し、評価を行った。
評価結果は、以下のとおり表す。
○：２試料ともクラックが発生しなかった
△：１試料でクラックが発生した
×：２試料ともクラックが発生した
(Initial crack resistance evaluation)
A simulated work prepared by using nuts, washers with external teeth, and hexagon bolts from the powder coatings of Examples and Comparative Examples is preheated in a blower drying furnace at 180 ° C. for 20 minutes, then fluidly immersed for 8 seconds, and then 180. It was cured by heating at ° C. for 1 minute. After curing, it was water-cooled for 5 minutes to remove water from the surface, left overnight, and visually confirmed for cracks. Two samples were prepared and evaluated for each Example and Comparative Example.
The evaluation results are shown as follows.
◯: No cracks occurred in both samples Δ: Cracks occurred in 1 sample ×: Cracks occurred in both samples
（耐ヒートサイクル性評価）
実施例及び比較例の粉体塗料で、積厚５０mm、外径４５mm、スロット数２１のスロット絶縁を施した模擬ワークを送風乾燥炉内で１８０℃で２０分予熱後、浸漬してから、１８０℃で２０分間加熱して硬化させた。硬化後、空冷し、室温となったところで、外周をスロットが見えるまで切削し、試験片を得た。これを低温−３０℃、高温１６０℃で各２時間を１サイクルとして、ヒートサイクル試験を実施し、スロット間のクラックの有無を目視で確認した。
評価結果は、以下のとおり表す。
○：１０サイクル以上でもクラックの発生が認められなかった
×：１０サイクル未満でクラックの発生が認められた
(Evaluation of heat cycle resistance)
A simulated work with a product thickness of 50 mm, an outer diameter of 45 mm, and slot insulation of 21 slots, which is the powder coating material of Examples and Comparative Examples, is preheated at 180 ° C. for 20 minutes in a blower drying furnace, then immersed, and then 180. It was cured by heating at ° C. for 20 minutes. After curing, it was air-cooled, and when it reached room temperature, the outer circumference was cut until a slot could be seen to obtain a test piece. A heat cycle test was carried out with this as one cycle at a low temperature of −30 ° C. and a high temperature of 160 ° C. for 2 hours each, and the presence or absence of cracks between the slots was visually confirmed.
The evaluation results are shown as follows.
◯: No cracks were observed even after 10 cycles. ×: Cracks were observed in less than 10 cycles.
（実施例３〜５）
表２に示す配合比（質量）で、実施例１と同様の方法により、粉体塗料を得た。実施例１と同様の方法で、粉体塗料の硬化物の線膨張係数、機械衝撃強さ及びガラス転移温度を測定し、耐初期クラック性評価を行った結果を表２に示す。
(Examples 3 to 5)
A powder coating material was obtained by the same method as in Example 1 at the compounding ratio (mass) shown in Table 2. Table 2 shows the results of initial crack resistance evaluation by measuring the coefficient of linear expansion, mechanical impact strength, and glass transition temperature of the cured product of the powder coating material in the same manner as in Example 1.
充填剤として炭酸カルシウムを用い、衝撃緩和剤としてコアシェルを用いた比較例１、充填剤としてシリカを用い、衝撃緩衝材を用いなかった比較例２及び充填剤としてシリカを用い、衝撃緩衝材としてコアシェルを用いたが線膨張係数が比較的高い比較例３では、いずれも初期クラック性評価で２つの試料に割れが生じた。
比較例４では、比較例１の組成比を変えることにより、線膨張係数が３６×１０-６／℃から２８×１０-６／℃に低減した。しかし、耐初期クラック性評価では、比較例１と同様２つの試料で割れが生じ、耐熱衝撃性の向上は認められなかった。また、比較例５及び６では、衝撃緩衝材を加えず、クレゾールノボラック型エポキシ樹脂の種類や組成比を変えることにより、比較例２より、線膨張係数が低減し、機械衝撃強さが向上した。しかしながら、耐初期クラック性評価では、比較例２と同様２つの試料で割れが生じ、耐熱衝撃性の向上は認められなかった。
これに対して、比較例３と同様、充填剤として、シリカを用い、衝撃緩和剤として、コアシェル粒子を用い、比較例３の組成比を変えることにより、線膨張係数を低減させた実施例１では、１つの試料に微細なクラックが発生したが、他方にはクラックは認められなかった。また、充填剤として、シリカを用い、衝撃緩和剤として、コアシェル粒子を用い、その他の組成を変えた実施例２では、実施例１と同等の線膨張係数及び機械衝撃特性が得られた。そして、耐初期クラック性評価では、いずれの試料にもクラックは認められず、熱衝撃性がさらに向上したことが確認された。
Comparative Example 1 in which calcium carbonate was used as a filler and a core shell was used as a shock absorber, Comparative Example 2 in which silica was used as a filler and no impact cushioning material was used, and silica was used as a packing material, and a core shell was used as a shock absorbing material. However, in Comparative Example 3 in which the coefficient of linear expansion was relatively high, cracks occurred in two samples in the initial crackability evaluation.
In Comparative Example 4, the coefficient of linear expansion was reduced from 36 × 10 -6 / ° C. to 28 × 10 -6 / ° C. by changing the composition ratio of Comparative Example 1. However, in the initial crack resistance evaluation, cracks occurred in the two samples as in Comparative Example 1, and no improvement in thermal shock resistance was observed. Further, in Comparative Examples 5 and 6, the coefficient of linear expansion was reduced and the mechanical impact strength was improved as compared with Comparative Example 2 by changing the type and composition ratio of the cresol novolac type epoxy resin without adding the impact cushioning material. .. However, in the initial crack resistance evaluation, cracks occurred in the two samples as in Comparative Example 2, and no improvement in thermal shock resistance was observed.
On the other hand, as in Comparative Example 3, silica was used as the filler and core-shell particles were used as the impact mitigating agent, and the coefficient of linear expansion was reduced by changing the composition ratio of Comparative Example 3. Then, fine cracks were generated in one sample, but no cracks were observed in the other. Further, in Example 2 in which silica was used as the filler, core-shell particles were used as the shock absorber, and other compositions were changed, the same linear expansion coefficient and mechanical shock characteristics as in Example 1 were obtained. Then, in the initial crack resistance evaluation, no cracks were observed in any of the samples, and it was confirmed that the thermal shock resistance was further improved.
充填剤としてシリカを用い、衝撃緩和剤としてシリコーン粒子を用いた比較例７では、実施例１及び２と同等の線膨張係数及び機械衝撃特性が得られ、耐初期クラック性評価でいずれの試料にもクラックの発生は認められなかった。しかしながら、耐ヒートサイクル性評価において、クラックの発生が認められ、高温となる電機子への適用は困難であることが確認された。なお、実施例では、耐ヒートサイクル性も良好であることが確認されている。
以上の結果から、ビスフェノールＡ型エポキシ樹脂、クレゾールノボラック型エポキシ樹脂、シリカ及びシェル層が（メタ）アクリル酸エステルを含むコアシェル粒子を含有する組成物から得られる粉体塗料において、粉体塗料の硬化物の線膨張係数及び粉体塗料を塗布後硬化して得られる塗膜の機械衝撃強さが所定の値となるように調製した本発明の粉体塗料では、得られる塗膜の初期クラックの発生が改善され、高温となる電機子への適用も可能であることが確認された。
ここで、比較例４〜７は、実施例１、２と同等の線膨張係数及び機械衝撃を有するにも関わらず、耐初期クラック性及び耐ヒートサイクル性に大きな差異が生じた。この理由としては、実施例で用いたシリカは炭酸カルシウムのように内部破壊が生じないことと、実施例のコアシェルとシリカの組み合わせでは、コアシェル粒子がシリカ及びエポキシ樹脂の双方と親和性が高いことにより、粉体塗料硬化物の接着強度及び剥離強度が向上したことが考えられる。
In Comparative Example 7 in which silica was used as the filler and silicone particles were used as the impact mitigating agent, the same linear expansion coefficient and mechanical impact characteristics as in Examples 1 and 2 were obtained, and any sample was evaluated for initial crack resistance. However, no cracks were observed. However, in the heat cycle resistance evaluation, cracks were observed, and it was confirmed that it was difficult to apply it to an armature having a high temperature. In the examples, it has been confirmed that the heat cycle resistance is also good.
From the above results, in a powder coating material obtained from a composition containing bisphenol A type epoxy resin, cresol novolac type epoxy resin, silica and core-shell particles containing (meth) acrylic acid ester, the powder coating material is cured. In the powder coating material of the present invention prepared so that the linear expansion coefficient of the object and the mechanical impact strength of the coating material obtained by curing after applying the powder coating material have a predetermined value, the initial cracks of the obtained coating material are generated. It was confirmed that the occurrence was improved and that it could be applied to an armor with high temperature.
Here, although Comparative Examples 4 to 7 had the same linear expansion coefficient and mechanical impact as those of Examples 1 and 2, there was a large difference in the initial crack resistance and the heat cycle resistance. The reason for this is that the silica used in the examples does not cause internal destruction unlike calcium carbonate, and in the combination of the core shell and silica of the examples, the core shell particles have high affinity with both silica and epoxy resin. As a result, it is considered that the adhesive strength and the peeling strength of the cured powder coating material are improved.
実施例３〜５では、ビスフェノールＡ型エポキシ樹脂の種類及び硬化剤の添加量を変えることにより、硬化物のガラス転移温度の異なる粉体塗料を作製した。ここで、ガラス転移温度が、１１７℃である実施例３に比べ、ガラス転移温度がそれぞれ１２３℃及び１２９℃の実施例４及び５の方が優れた熱衝撃性を有することが確認された。ガラス転移温度の高い実施例４及び５の効果は、高温負荷試験でより明確に認められる。なお、ガラス転移温度が、１１５℃であれば、耐初期クラック性及び耐ヒートサイクル性とも良好であることが確認されている。このため、硬化物のガラス転移温度は、１１５℃以上が好ましく、１２０℃以上がより好ましいといえる。ただし、ガラス転移温度が１４０℃を超えると、樹脂が脆くなり機械衝撃強さが低下しやすいため、粉体塗料の硬化物のガラス転移温度は１４０℃以下とすることが好ましく、１３０℃以下とすることがより好ましい。
In Examples 3 to 5, powder coating materials having different glass transition temperatures of the cured product were produced by changing the type of the bisphenol A type epoxy resin and the amount of the curing agent added. Here, it was confirmed that Examples 4 and 5 having glass transition temperatures of 123 ° C. and 129 ° C. had superior thermal shock resistance as compared with Example 3 in which the glass transition temperature was 117 ° C. The effects of Examples 4 and 5 with high glass transition temperatures are more clearly observed in the high temperature load test. It has been confirmed that when the glass transition temperature is 115 ° C., both the initial crack resistance and the heat cycle resistance are good. Therefore, it can be said that the glass transition temperature of the cured product is preferably 115 ° C. or higher, more preferably 120 ° C. or higher. However, if the glass transition temperature exceeds 140 ° C, the resin becomes brittle and the mechanical impact strength tends to decrease. Therefore, the glass transition temperature of the cured product of the powder coating material is preferably 140 ° C or lower, preferably 130 ° C or lower. It is more preferable to do so.
Claims (3)
前記コアシェル粒子のシェル層は、（メタ）アクリル酸エステルを含有し、
前記粉体塗料の硬化物の５０℃〜９０℃における線膨張係数は、３５×１０-６／℃以下であり、
前記粉体塗料の硬化物のガラス転移温度は１１５℃以上１４０℃以下であり、
前記粉体塗料を塗布後硬化して得られる４００μｍの塗膜の機械衝撃強さは、３０ｃｍ以上であることを特徴とする粉体塗料。 A powder coating material obtained from a composition containing a bisphenol A type epoxy resin, a cresol novolac type epoxy resin, silica and core-shell particles.
The shell layer of the core-shell particles contains a (meth) acrylic acid ester and
The coefficient of linear expansion of the cured product of the powder coating material at 50 ° C. to 90 ° C. is 35 × 10 -6 / ° C. or less.
The glass transition temperature of the cured product of the powder coating material is 115 ° C. or higher and 140 ° C. or lower.
A powder coating material having a mechanical impact strength of 30 cm or more of a coating film of 400 μm obtained by applying and curing the powder coating material.
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