JPS6035019A - Epoxy resin curing accelerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Prior art 2? Oxy resins can be cured by the application of acid anhydrides and heat. Typical acid anhydrides used are phthalic acid, hexahydrophthalic acid, succinic acid, dodecenylsuccinic acid, and maleic acid.

Adduct of methylcyclopentadiene and maleic acid.

Methyltetrahydrophthalic acid, trimellitic acid anhydride, and 3.3', 4.4'-benzophenone tetracal are phosphoric acid dianhydrides. The anhydride must undergo ring opening for cure to occur, and this can be facilitated and caused to occur at lower temperatures by the addition of small amounts of proton-containing compounds, such as amines. Typical common accelerators used in epoxy/anhydride systems are benzyldimethylamine, 2,4.6-)lith(
dimethylamine methyl)phenol, 2-ethyl-4-
Methylimidazole and stannous octoate.

Engineering? Oxy resins will also react with carboxyl acids at high temperatures, and the fact that solid epoxy resins are mixed with solid polyester resins containing free carboxyl groups, either at the end of the chain or in the side chains. used in powder coatings that are heated and cured. In this application, accelerators are often used and some of those described in the literature include:=rlJ:/rit:II) FCIP-A-
0010805) and heterocyclic compounds such as imidazole and 2-methylimidazole (GB151607)
7 and GB1558303).

(3) Structure of the Invention We now propose that benzotriazoles, including those with aromatic ring substitution, can be used in combination with compounds containing epoxy groups and cardanic acid compounds, such as polyester forms having free carboxyl groups at the chain ends or in the branches. It has been found that it behaves as a curing accelerator or catalyst for the reaction between compounds present in

Preferably, such a benzotriazole has the formula:
It is a lower alkyl such as H3. ), the R group may assume any position on the benzene nucleus,
Mixtures of isomers may also be used.

Particularly good powder coatings are from polyoxyde resins based on bisphenol compounds such as Epicote 1055 (4) or Araldite GT7004, or polyoxygen-containing compounds such as triglycidyl isocyanurates (e.g. Araldite PT810). Obtainable.

Other types of epoxy resins include, for example, epoxy resins with a melting point of 50°C or higher. A rack-based one or the like can be used.

Typical ester resins that can be used include symmetrical glycols, such as neopentyl glycol, and one or more aromatic radicals. based on acidic acids, such as isophthalic acid or terephthalic acid, the acid content of which is optionally additionally provided by an aliphatic mono- or dicardic acid, such as pelargonic acid, pericic acid or trimellitic anhydride. It will be done. The polyester preferably has an acid value of 30 to 1001R9KO l, a melting point of 50 to 70°C and a melt viscosity of 10 to 40 poise at 200°C (1, C, 1, when measured using a cone-plate viscometer). ).

Powder coatings include epoxy, polyester and hardening accelerators, plus pigments to obtain the desired color tone.

Flow control agents and light stabilizers may be included.

EXAMPLES Preferred reactions embodying the invention are described with respect to the following examples, including a comparison between the performance of the promoter used in the reaction embodying the invention and that of reactions carried out with conventional promoters. Good morning.

Example (ii) The I-reester was prepared from 5.3 mol of neopentyl glycol and 4.3 mol of terephthalic acid by reaction at 200-240 DEG C. to an acid number less than 10 m9 KOH/I. 1 mol of trimellitic anhydride was added, and the reaction was further carried out at 190-200° C. until an acid value of 80-901n9KOH7/11 was reached.

Continued cooling yielded a solid resin that could be easily powdered.

A series of powder coatings were prepared using the following formulations:
W Epicoat ■1055 (solid epoxy foam) 100p
bW titanium dioxide (pigment) to o pbW benzoin (light stabilizer) 2pbW Modaflow■ (flow regulator) 2pbW curing accelerator* 0~l, Qpbw Umbrella 6) Choline chloride (c) Imidazole (c) Benzotriazole Dry blend Afterwards, the ingredients were passed through an extruder at 1000 ml and ground into powder. The gluing times of the various formulations were determined at 155°C using the "strokedling time" on a hot plate (Method 8 of B, S, 2782).
35D:1980) The results shown in Figure 1 indicate that benzotriazole is a curing accelerator and that it is even more effective than choline or imidazole.

Example■ Polyester resin, the following compound, 10■KOIp
◎ Neopentyl glycol 3649 Terephthalic acid 423 g Adipic acid 411I Fameat ■ 4201 (esterification catalyst) 311 Water
2Bg Water was present to form a slurry so that the reaction mixture could be stirred. Next, 1419 trimellitic anhydride was added, and further condensation was carried out until an acid value of 80±5 ■KOl ω was reached.

The solid polyester had a melting point of 57°C and a melt viscosity of approximately 20p at 200°C.

Powder coatings were made from the resin by powdering and dry blending the following material formulations.

Polyester resin (as above) 100 pbW Araldite ■GT7004 (epoxy resin) toopb
wKronos CL310 (titanium dioxide pigment)
o o pbW benzoin 2 pbw Modaflow ■ 2 pbW curing accelerator O ~ 1.0 pbW The mixture was then extruded at a melt temperature of 120-125°C and the cooled product was ground to give a powder 4 India having a particle size of less than 100μ. Ta. It can be sprayed electrostatically and cured for 10 minutes at a temperature of 200°C.

To save energy costs, it is desirable to reduce the temperature and curing time, and this can be done by incorporating curing accelerators. Stroke time is a measure of the time required to cure. The results are shown in Table I.

Margin table below ■ Choline chloride 0 1240 6000.025 8
25 380 0.25 300 112 0.75 225 85 Imidazole 0 1240 600 0.025 825 450 0.25 300 160 0.75 225 90 -Mutsul Tria2 Pre 0 1240 6000.0
25 600 300 0.25 250 110 0.75 175 80 Margin below These numbers demonstrate the greater effectiveness of benzotriazole as a curing accelerator compared to the usual accelerators choline chloride and imidazole. .

EXAMPLE ■ A four-reester resin was prepared by condensing the following formulation at 200-240° C. until an acid number of less than 20 ■ KOVII was obtained.

Neopentyl glycol 5309 Terephthalic acid '11111 Isophthalic acid 88Ii Pelargonic acid 589 Fascat 4201 5 & Water 3011 Next, 42.6F trimellitic anhydride was added,
The reaction was continued to an acid value of 35±5 M9Koa7'y.

A mixture of 90 pbw of the above polyester, 1 OpbW of Araldite PT810 (liglycidyl isocyanurate), 5 Q pbw of titanium dioxide pigment, 1 pbW of flow control agent and 0.0.11 and 0.3 k of benzotriazole. It was prepared, extruded and further powdered.

The stroke gluing times for these combinations are shown in Table ■.

Table■ 0 600 200 0.1 260 190 0.3 200 90 Example■ ? Lyester resin was added to the following formulation at 10 mpKo)M
, P or less was obtained by heating at a temperature of 200 to 240°C.

Neopentyl glycol 364Ii Terephthalic acid 423g Adipic acid 419 Faseat 4201 (esterification catalyst) 311 Water
28g Reaction Water was present to form a slurry so that the reactants could be stirred. Next, 1411 trimellitic anhydride was added and further Vc80±51vK
Condensation was carried out until an acid value of OH/11 was reached.

The resin was mixed with an equal amount of Araldite GT 7004 epoxy resin and powdered.

To two portions of this mixture were added 0.5 weight portions of tolyltriazole (8atrdoz TT-100) and benzotriazole, respectively. The gluing time was set to 155 using the stroke gluing time on the hot plate.
Measured at 180 °C and 180 °C (B, S.

2782: Method 835D).

4A No additive 125 250 4B) Lyltriazole 51 1354C Benzotriazole 59 124 or less margin (14) When benzotriazole or tolyltriazole is used as a curing accelerator in the reaction according to the present invention, the dulling time is greatly reduced. I can understand that.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the amount of accelerator added and the gluing time. Patent applicant Scott Heiter Kannohi Limited Patent agent Akira Kenki Patent attorney Kazuyuki Nishidate Patent attorney Yoshi 1) Takeo Patent attorney Akira Yamaguchi Patent attorney Masaya Nishiyama Engraving of the drawing (no changes to the content) 1st Figure gelation time (5ecs) 155°C 00 1\ 1\ 1\ \ \ \ \ \ , \ Su \ \ \ ゝ, \ \ \ ′-7・Suuri・RidoゞX ＼口〜 ゝ−−− −−−−−o−−7mu tab−′
\- (15) Procedural amendment (method) % formula % 1. Indication of the case 1982 Patent Application No. 95770 2. Name of the inventor is curing accelerator for xy resin 3. Relationship with the person making the amendment case Patent applicant name Scotto Bader Kanno Kuni Limited 4, Agent 6, Drawings to be amended 7, Contents of amendment: engraving of drawings (no change in content) 8, Attached document catalog engraving drawings 1 copy

Claims (1)

[Claims] 1. A method of reacting a compound containing an epoxy group with a carboxylic acid compound, the method comprising the presence of a promoter characterized in that it is a benzotriazole optionally substituted on an aromatic ring. , a method comprising heating a mixture of a compound containing an epoxy group and a carboxylic acid compound. 2. The method according to claim 1, wherein the benzotriazole has the formula (wherein R is none or C1-4 alkyl). 3. The benzotriazole is unsubstituted benzotriazole or tolyl. The method according to claim 2, wherein the carboxylic acid compound is a triazole, and the method according to claim 1, wherein the liberated carboxylic acid compound is a polyester containing a xyl group.
The method described in any of paragraphs 3 to 3. 5. The method according to claim 4, wherein the compound containing an epoxy group is an epoxy resin. 6. The method according to claim 5, wherein the epoxy resin is based on bisphenols. 7. The method according to any one of claims 1 to 4, wherein the compound containing a nibkis group is triglycidyl isocyanurate. 8. the polyester comprises glycol units derived from neopentyl glycol and acid units derived from one or more of terephthalic acid and isophthalic acid;
A process according to any of claims 4.5.6 and 7, in which the acid residue optionally additionally contains units derived from mono- or di-cardic acid. 9. Benzotriazoles optionally polysubstituted in the aromatic ring for use as promoters for the reaction between compounds containing epoxy groups and carboxylic acid compounds. 10. A benzotriazole according to claim 9 for use as a promoter for the reaction between an epoxy compound and a polyester containing free carboxyl groups.