JPS58125760A - Metal coating paint - Google Patents

Abstract

PURPOSE:To provide the titled paint having balanced processability, adhesivity, and rapid curability, and useful for the coating of cans, by using a branched epoxy resin composed of a compound having specific number of glycidyl groups, a phenolic compound having specific number of OH groups, and if necessary a curing component. CONSTITUTION:The objective paint is prepared by compounding (A) a branched epoxy resin obtained by compounding (i) a compound having two glycidyl groups (e.g. bisphenol A diglycidyl ether, etc.), (ii) a compound having >=3 glycidyl groups (e.g. novolac-type epoxy resin) and (iii) a phenolic compound having >=2 phenolic OH groups (e.g. bisphenol A) at a weight ratios of (65-10):(0.5-60): (20-40), if necessary with (B) a curing component (e.g. resin curing component) at a ratio A:B of (95-5):(5-95).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paint for coating metals with excellent curability using a branched epoxy resin, and more particularly to a paint useful as a conventional paint.

In recent years, there has been a remarkable improvement in the performance of cans as containers, and materials, shapes, manufacturing methods, etc. have expanded to a wide range, and a wide variety of functional materials and materials with good performance are now required.

In addition, for conventional paints, typical methods include coil coating systems or two-piece action high-speed ovens.
It is aimed at short-curing times. In order to respond to these circumstances, the composition of conventional paints has become more complex in terms of resin components, auxiliary agents, and solvents, and many have achieved a delicate balance in performance.

However, regarding the core resin component, in this field,
There is little movement to meet new requirements with new resins, and there are many examples of achieving a balance of performance based on conventionally used resins.

In particular, in the case of paints whose main component is epoxy resin, the epoxy resin often accounts for 50 to 90% of the paint resin. Only different types and different average molecular weights are used.

Looking more closely, epoxy resins used in combination with phenolic resins, amino resins, etc. have an epoxy equivalent of 15
2 grades of 00 to 3300 (equivalent to 1007° and 1009 manufactured by Yuka Shell Epoxy Company), and 1 grade with an epoxy equivalent of about 500 (Epicoat ≠ 1004 manufactured by Yuka Shell Epoxy 61 Company) for esterification with fatty acids. It is mainly used as an epoxy resin and is limited to a very narrow range, and the actual situation is that changes in performance depend on the mixing ratio with other components and changes in other components.

Of course, these medium- to high-molecular-weight grade shrimp-bis type epoxy toilet fats have excellent properties such as good elasticity, adhesion, and chemical resistance, and can be put to practical use as conventional paints by carefully selecting the combination of ingredients. Although sufficient performance has been obtained, the structure is a linear structure with glycidyl groups at both ends, and in order to improve the above performance, as the molecular weight increases, the glycidyl group content decreases and reactivity decreases. I am facing this problem.

Therefore, it is extremely difficult to perform short-time curing or precise crosslinking curing with a composition containing a large amount of high molecular weight epoxy resin.

In addition, when looking at the physical properties of the coating film, the lower the molecular weight grade, the better the adhesion to metal, and the more noble the polymer grade, the better the processability.
I'm n. In the case of conventional paints, they are often subjected to coating film formation φ and processing, and the adhesion of processed parts is often a problem that overlaps with the performance of the final product. Therefore, a balance of excellent workability and adhesion is required, but in the case of paints based on epoxy resin, depending on the grade of epoxy resin used,
It is difficult to obtain a particularly excellent balance of performance since certain performance limits have been established.

The inventors of the present invention have diligently studied ways to overcome this current situation, and have created a resin with a high molecular weight but a low epoxy equivalent, by creating a branch in the main chain of the epoxy resin and placing an epoxy group at the end of the branch. By using a branched epoxy resin that combines the advantages of conventional high-molecular-weight grades and low-molecular-weight grades, we can create coatings for epoxy threads with an excellent balance of workability, adhesion, and fast curing. I found out what I can get.

The epoxy resin used in the present invention is prepared by reacting a compound with two glycyl groups (A), a compound with three or more glycyl groups (B'l, and divalent or trivalent or higher phenols (C)). It is a branched epoxy resin.

Examples of the compound (A) having two glycyl groups according to the present invention include resorcinol diglycidyl ether, bisphenol F diglycidyl ether, bisphenol A diglycidyl ether, and Mata is a commercially available shrimp type epoxy resin. Bis-type epoxy resin supply≠F咋direction°゛ - Among these, the low molecular weight grade is preferable because it retains the advantages of the bis-type high molecular weight epoxy resin and is easily available.

Chemical compounds (B) having 31 or more glycyl groups include trihydroxybenzene glycidyl ether, pentaerythritol glycidyl ether, glycidyl ether of polyphenols, etc., but novolac type epoxy u
The contention using the substance (molecular weight 400 to i, ooo) is
Preferred in terms of physical properties.

21ifl+ moL < (d Regarding trivalent or higher phenols, resorcinol, catechol, bisphenol A1, bisphenol F,) lyhydroxybenzene, etc. can be mentioned, but the skeleton will be similar to the current shrimp-bis type. From this point of view, bisphenol A is preferred.

To synthesize the epoxy resin according to the present invention, a compound having two glycidyl groups (A), a compound having three or more glycidyl groups (B), and a divalent or trivalent or higher phenol (C) are mixed, It is obtained by heating and melting, adding a catalyst to promote the reaction if necessary, and heating and stirring. Examples of the catalyst include caustic soda and triphenylphosphine.

There is no particular restriction on the blending ratio of each component (d), but if the amount of the compound (B) having 31 or more glycidyl groups becomes too large, the degree of branching will increase, and in order to prevent If you keep it low, a lot of unreacted substances will remain,
In addition to its performance as an epoxy resin, the compound vJ (
By reducing the blending amount of B), the difference from normal shrimp/bis type epoxy resin will be reduced, and this can be used for metal coating,
Even if the paint for cans is removed, there will be almost no noticeable difference in performance balance. To express this more precisely, what if there is one branch from the main chain? When expressed as a degree of branching of 1, an average branching vo of 1 to 3.0 is appropriate.

That is, if it exceeds 3t-i4, there is a very high risk of kelization, and if it is less than 0.1, it is difficult to exhibit characteristics. It should be noted that at a level below 1", it may seem like there is a shortage, but in reality the product is not uniform, but is a mixture of those with a degree of branching of 1 or more and those with almost no branching, with an average of 0.1 It is clear that a better performance balance than that of 0 can be obtained. Therefore, the 11 ratio (weight ratio) of components (A), (B), and (c) is (*):(B):(c) ~65~10:5~6
The range from 0:20 to 40 is suitable. The resin obtained in this range has a weight average molecular weight of 8,000 to 80.
,000° number average molecular weight 1,500 to 5,000, Epoxy 1R equivalent weight 500 to 2000, and for example, representative products of the engineering male and screw type (Ebiko) 1007 weight average molecular weight 4200° number average molecular weight 11700° Epoxy. Compared to fi1940 (actually measured), it has the characteristics of a wider molecular weight distribution and a lower epoxy equivalent. In addition, in order to obtain practical performance as a disc paint, it is common to combine it with a curing component, and in the case of the present invention, phenol resin, urea resin, benzoguanamine resin, polyamide resin, melamine resin, acrylic resin, etc. It can be used in combination with a resin-based curing component or a low molecular weight curing component such as a metal chelate or amine to form a thermosetting paint for metal damage or for use in publicity.

It is also possible to make an oxidative polymerization type paint by esterifying it with a fatty acid.
There is no problem in using it as a paint in combination with melamine resin or the like.

Of course, it can be made into a paint by handling it in the same way as general shrimp/bis type epoxy resin, such as by making it water-soluble by modifying it with acrylic acid or by combining it with the above-mentioned curing components to make a powder paint.

The blending amount may be set depending on the application, but in combination with a resin-based curing component, branched epoxy resin:resin-based curing component = 95:5-5;
A range of 95 is preferred. In addition, in combination with low-molecular noble hardening components such as metal chelates, branched epoxy resin: hardening component = 80:20 to 99:1
A range of is preferred.

In addition, when turning it into a paint, it can be used for general epoxy metal coating,
Preferably, surfactants and
Components such as lubricants or pigments such as titanium oxide and zinc oxide may be added.

The gold powder of the present invention is useful for the disc paints mainly explained above, but it is also effective for other uses such as disc paints that require various physical properties. In the present invention, the term "for metal coating" includes not only cases in which the metal plate is directly coated, but also cases in which the metal plate is coated with other paints or primers.

<Manufacturing Example of Branched Epoxy Resin> The epoxy resin used in the examples of the present invention was prepared as follows.

Epoxy tree N11i! -1 (parts by weight) Epiput+8211 (shrimp-bis type epoxy resin manufactured by Jigyo Shell Epoxy Co., Ltd.) 5! LODICM4
3B (novolac type epoxy resin manufactured by Dauke Zecal)
15゜Bisphenol A

29J triphenyl 7 male twin
0.1 (total too, o) When the above four substances are heated and stirred, due to the heat of reaction,
Raise the temperature to 180°C. The temperature starts to drop after about 10 minutes, but the temperature is maintained at 175-180'C, and the reaction is continued for 1 hour. After the reaction was completed, the mixture was cooled to obtain a solid resin.

The obtained resin had a number average molecular weight of 3100. Weight average molecular weight 58000, epoxy i1920. The viscosity was xy (Gardner bubble viscometer, 25°0, 40% solution).

Example 1 13゛.

The branched epoxy resin EX-1 shown in the production example was replaced with a urea resin (Super Beckamine P-138 manufactured by Leipihold).
The branched epoxy resin:urea resin was mixed in a solid content ratio (weight ratio) of 80/20, and the whole was dissolved in butyl cellosolve to form a paint with a solid content of 30%.

The resulting paint was coated to a thickness of 0.5 μm so that the dry film thickness was 5 μm.
23&), was coated on a tin plate with a tin content of 50 using a roll coater, and then baked in a hot air dryer at 200'C for 10 minutes to obtain a test piece.

Vertical cellophane tape peeling test on test piece, 1
Retort resistance test of 25°0160 minutes, drawing ratio 2, O
A cup punching test was conducted.

Example 2 The resin mixing ratio of Example 1 was changed from 80/20 to 90/10.

Example 3 The baking conditions of Example 1 were changed to 200°C and 5 minutes.

Example 4 A test was carried out except that the baking condition of Example 2 was changed to 200°C for 5 minutes.

Comparative Examples 1 to 4 Implementation v] Yuka shell epoxy (Ebi Cortner 1007 manufactured by Co., Ltd.) was used instead of the branched epoxy resin in 11 to 4.

Comparative Examples 5 to 8 Comparative Examples 1 to 4 were carried out using oily shell epoxy tl [Epicote" 1009 instead of the branched epoxy apricot I fat in Examples 1 to 4.

<Example of manufacturing branched epoxy resin> Nipokiri resin ZX-Z Ebipushi
Screw type epoxy resin 141. @127+1201+Nobotsutata original epoxy resin manufactured by Nippon Kashu)
104 screw 7m norm
wh.

lterce four norpe
zs.

The above four substances were dissolved by heating, stirred continuously at 175°C for 3 hours, and then cooled to obtain a resin solution.

The obtained resin has several thousand equivalents +i [i449 B, weight average molecular 'f120519, epoxy equivalent weight 944, viscosity X-
Y (Gardner bubble viscometer, 25°C1 Example 5 Branched epoxy resin EX-2 all-sol type phenolic resin shown in the production example (Hitachi Chemical Hytanol 4010)
were mixed so that the solid content ratio (weight ratio) of branched epoxy resin:phenol ratio was 75/25, and the whole was dissolved in cyclohexanone to form a paint with a solid content of 30%.

The resulting paint was coated with a thickness of 0 so that the dry film thickness was 5μ.
．． After coating a tin plate with a diameter of 231 L and a lead content of 50 using a roll coater, it was placed in a hot air dryer and baked at 200°C for 110 minutes to obtain a test piece.

No. 1 was made using the painted surface of the test piece as the inner surface.

Each lid was also made from the same specimen.

Next, the boiled mackerel was repacked in the resulting can, and after wrapping it tightly, it was retorted at 118°C for 90 minutes.
After being stored at 50°C for one month, blackening due to sulfurization and whitening of the paint film were observed. In addition, a cup punching test similar to Examples 1 to 4 was conducted.

Comparative Example 9 A test was carried out using Epicoat 1007t manufactured by Yuka Shell Epoxy Co., Ltd. as the base of the branched epoxy resin of Example 5.

Table 2 As is clear from the results in Table 1, Examples 1.2.3.4 using branched epoxy resins have a good balance of adhesion, retortability, and processability, and can be baked for a short time. It is demonstrating its performance.

This is an excellent balance of performance that cannot be obtained with conventionally used shrimp/bis type epoxy resins.

In addition, in Example 5 shown in Table 2, even when combined with phenolic resin, the characteristics of branched epoxy hatsumode were excellent, such as high crosslink density seen in sulfide black seismic properties and cup punchability. It is recognized for its high workability balance.

As is clear from these results, it can be seen that there is a great possibility that a coating film with physical properties that could not be expected up to now can be obtained by combining various resins.

Patent Applicant: Toyo Ink Manufacturing Co., Ltd. (Volunteer to write procedural amendments) March 1, 1980 To the Commissioner of the Japan Patent Office 1. Indication of the case: Patent Application No. 7692 of 1980 2. Title of the invention: Paint for coating metals 3. Amendment Patent applicant 4, “Claims” and “Detailed description of the invention” column 5 of the specification to be amended, Contents of the amendment Correction of the description 1, Patent claims as attached The scope shall be as shown in the attached sheet.

2. Detailed description of the invention (1) Page 9, line 19 of the specification “65-10:5-60:
20-40" to "65-10: 0.5-60:20
~40''.

Claims ■: A branched epoxy resin obtained by reacting a compound (A) having two glycidyl groups, a compound (B) having three or more glycidyl groups, and a divalent or trivalent or higher phenol (C). , and further a curing component if necessary.

2. The metal coating paint according to claim 1, wherein the compound (A) is bisphenol A diglycidyl ether.

3. The metal coating paint according to claim 1 or 2, wherein the compound (B) is a novolac type epoxy resin.

4. The metal coating paint according to any one of claims 1 to 3, wherein the phenol (C) is bisphenol A.

5. (A), (B) and (C) in a weight ratio of 6
The paint for metal coating according to any one of claims 1 to 4, which uses a branched epoxy resin reacted at a ratio of 5 to 10 K to 60 to 20 to 40.

6. A resin-based curing component is used as the curing component, and the weight ratio of the branched epoxy resin and the curing component is 95 to 5:5.
The paint for metal coating according to any one of claims 1 to 1, which is used in a ratio of 95% to 95%.

Claims (1)

[Scope of Claims] 1. A branched compound obtained by reacting a compound (A) having two glycidyl groups, a compound having three or more glycidyl groups* (B), and a divalent or trivalent or higher phenol (c). A paint for gold citron, characterized by using epoxy #+B"FT and a curing component as necessary. 2. (A patent in which the compound of A'+ is bisphenol A diglycidyl ether. 3. (Metal coating as described in Claim 5, Claim 1 or 2, in which the ammonium compound of Bl is a novolak-type epoxy resin) Rumor 4. The paint for breaking metal rods according to any one of claims 1 to 3, wherein the hard phenol in (c) is bisphenol A. 5. (A), (B), and (C) 6 in terms of heavy wages
A coating material for use on metal plates according to any one of claims 1 to 4, which uses a branched epoxy resin reacted in a ratio of 5 to 10:5 to 60:20 to 40. 6, @! &j fat-based hardening component is used as a chemical component, and the weight ratio of branched epoxy fat and hardening component is 95%.
Claim 1 used at a ratio of ~5:5-95
Gold PA coating paint according to any one of Items 1 to 5.