JP2002155204A - Heat-resistant resin composition and coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyamide-imide resin-based heat-resistant resin composition having excellent heat resistance and adhesivity after curing at a high temperature of >=350 deg.C and excellent processability and a coating comprising the heat-resistant resin composition as a coating film component. SOLUTION: This heat-resistant resin composition comprises 100 pts.wt. of a polyamide-imide resin (A) which is obtained by reacting an aromatic diisocyanate component represented by general formula (I) (R1 and R2 are each independently a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom) with a tribasic acid anhydride and has a repeating unit represented by general formula (II) (R3 is a trifunctional organic group) and 10-250 pts.wt. of a polyamide-imide resin (B) which is obtained by reacting an aromatic diisocyanate component (except the aromatic diisocyanate component represented by general formula (I) is omitted) with a tribasic acid anhydride and has a repeating unit represented by general formula (III) (R4 is a bifunctional group). This coating comprises the heat-resistant resin composition as a coating film component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat-resistant resin composition and a paint.

[0002]

2. Description of the Related Art Polyamide-imide resins are excellent in heat resistance, chemical resistance and solvent resistance. Therefore, they are used as coating components of various coatings such as varnishes for enameled wires to form protective coatings on various substrates. In particular, it is widely used for forming a heat-resistant protective coating. Known polyamideimide resins include those obtained by reacting diphenylmethane-4,4'-diisocyanate with trimellitic anhydride.

In recent years, in the field of heat-resistant paints, the method of applying paint has been changing from the conventional post-coating method to the pre-coating method from the viewpoint of omitting the coating process, shortening the construction period, and taking measures against pollution.
Therefore, it is required that the coating film has excellent heat resistance and adhesion, and further has excellent workability (bending property). However, heat-resistant protective coatings containing a polyamideimide resin as a coating component have excellent heat resistance and adhesiveness, but have poor processability, and have a disadvantage that the tendency is remarkable when the curing temperature is 350 ° C. or higher. Was.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a polyamideimide resin-based heat-resistant resin composition having excellent heat resistance and adhesiveness after curing at a high temperature of 350 ° C. or higher, and furthermore, to the heat-resistant resin composition. It is intended to provide a paint containing a product as a coating film component.

[0005]

The present invention relates to a compound represented by the general formula (I):

Embedded image (Wherein R ¹ and R ² independently represent a hydrogen atom, an alkyl group,
(Representing an alkoxy group or a halogen atom) represented by the general formula (II) obtained by reacting an aromatic diisocyanate component represented by

Embedded image (Wherein R ¹ and R ² independently represent a hydrogen atom, an alkyl group,
An alkoxy group or a halogen atom, and R ³ represents a trivalent organic group), and 100 parts by weight of a polyamide-imide resin (A) having a repeating unit represented by the formula (I): General formula (III) obtained by reacting anhydrous trihydrochloric acid with

Embedded image (Wherein, R ³ represents a trivalent organic group, and R ⁴ represents a divalent organic group). The present invention relates to a conductive resin composition.

The present invention also relates to a heat-resistant resin composition in which the content of the aromatic diisocyanate represented by the general formula (I) in the total diisocyanate component as a raw material of the polyamide-imide resin (A) is 20 to 90 equivalent%. About things. The present invention also provides the polyamide-imide resin (B)
Relates to a heat-resistant resin composition having a number average molecular weight of 10,000 to 50,000. Furthermore, the present invention relates to a paint containing the heat-resistant resin composition according to any of the above as a coating film component.

[0007]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a basic polar solvent is generally used for synthesizing a polyamideimide resin. Examples of the basic polar solvent used herein include N-methyl-2-pyrrolidone, dimethylacetamide, dimethylformamide, and the like. It is preferable to use a high boiling point solvent such as The amount used is not particularly limited, but may be 1 to 100 parts by weight of the total amount of the diisocyanate component and the aromatic tribasic anhydride.
The content is preferably in the range of 00 to 500 parts by weight.

Specific examples of the aromatic diisocyanate compound represented by the general formula (I) include, for example, biphenyl-
4,4'-diisocyanate, biphenyl-3,3'-
Diisocyanate, biphenyl-3,4'-diisocyanate, 3,3'-dichlorobiphenyl-4,4'-diisocyanate, 2,2'-dichlorobiphenyl-4,
4'-diisocyanate, 3,3'-dibromobiphenyl-4,4'-diisocyanate, 2,2'-dibromobiphenyl-4,4'-diisocyanate, 3,3'-
Dimethylbiphenyl-4,4'-diisocyanate,
2,2'-dimethylbiphenyl-4,4'-diisocyanate, 2,3'-dimethylbiphenyl-4,4'-diisocyanate, 3,3'-diethylbiphenyl-4,
4'-diisocyanate, 2,2'-diethylbiphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, 2,2 '
-Dimethoxybiphenyl-4,4'-diisocyanate, 2,3'-dimethoxybiphenyl-4,4'-diisocyanate, 3,3'-diethoxybiphenyl-4,
Examples thereof include 4'-diisocyanate, 2,2'-diethoxybiphenyl-4,4'-diisocyanate, and 2,3'-diethoxybiphenyl-4,4'-diisocyanate. These may be used alone or as a mixture of two or more.

[0009] Among the above aromatic diisocyanate compounds, 3,3'-dimethylbiphenyl-4,4'-diisocyanate represented by the following formula [trade name: TODI (Japan) Soda Co., Ltd.) is most preferably used in the present invention.

[0010]

Embedded image

In the synthesis of the polyamide-imide resin (A), the aromatic diisocyanate represented by the general formula (I) is preferably used in an amount of 20 to 90 equivalent% of the total isocyanate component. When the amount is less than 20 equivalent%, the effect is not sufficiently exhibited. When the amount exceeds 90 equivalent%, the processability of the coating film tends to gradually decrease, and the coating tends to undergo phase separation over time. For this reason, the content is preferably 30 to 80 equivalent%, particularly preferably 40 to 70 equivalent%.

Other diisocyanates which may be contained in the diisocyanate component together with the aromatic diisocyanate compound represented by the general formula (I) include, for example, diphenylmethane-4,4'-diisocyanate and diphenylmethane-3,3'- Diisocyanate, diphenylmethane-3,4'-diisocyanate, diphenylether-4,4'-diisocyanate, benzophenone-4,4'-diisocyanate, diphenylsulfone-
4,4'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate,
Various conventionally known diisocyanate compounds such as m-xylylene diisocyanate and p-xylylene diisocyanate are exemplified. These may be used alone or as a mixture of two or more.

The tribasic anhydride used in the present invention includes trimellitic anhydride, and the tribasic anhydride chloride includes trimellitic anhydride chloride. When synthesizing the polyamide-imide resin, dicarboxylic acid, tetracarboxylic dianhydride and the like can be simultaneously reacted within a range that does not impair the properties of the polyamide-imide resin.

The dicarboxylic acids include terephthalic acid, isophthalic acid, adipic acid and the like. The tetracarboxylic dianhydrides include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride. Anhydrides and the like.

The amount of the diisocyanate compound, tribasic anhydride or tribasic anhydride chloride, and optionally dicarboxylic acid and tetracarboxylic dianhydride used, depends on the molecular weight of the resulting polyamideimide resin, From the viewpoint of the degree, the diisocyanate or diamine compound is preferably 0.8 to 1.1 mol, more preferably 0.95 to 1.08 mol, and particularly preferably 0.95 to 1.08 mol based on 1.0 mol of the total amount of the acid component. , 1.0 to 1.08 mol. In the acid component, the total amount of dicarboxylic acid and tetracarboxylic dianhydride is 0 to 50.
It is preferably used in the range of mol%.

In the present invention, a polyamide-imide resin (B) obtained by reacting a diisocyanate other than the general formula (I) with an acid component is an essential component. The component (B) preferably has a number average molecular weight of 10,000 to 50,000. If the number average molecular weight is less than 10,000, the film-forming property of the resulting coating film tends to decrease, and
If it exceeds 0, the viscosity becomes high when dissolved in a solvent so as to have a proper concentration as a coating, and the workability at the time of coating tends to be poor.

The number average molecular weight of the polyamideimide resin is sampled at the time of resin synthesis, measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve, and synthesized until the desired number average molecular weight is reached. Can be managed within the above range.

The diisocyanate component used in the polyamideimide resin (B) is a diisocyanate other than the general formula (I), for example, diphenylmethane-4,4'-diisocyanate, diphenylmethane-3,3'-diisocyanate, diphenylmethane-3,4. '-Diisocyanate, diphenylether-4,4'-diisocyanate, benzphenone-4,4'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, tolylene-2,4'-diisocyanate, tolylene-2,
6'-diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, paraphenylene diisocyanate and the like. These may be used alone or as a mixture of two or more.

The heat-resistant resin composition of the present invention contains the polyamide-imide resin (A) and the polyamide-imide resin (B).
Is 10 to 250 parts by weight based on 100 parts by weight of the polyamide-imide resin (A). If the amount is less than 10 parts by weight, the effect will not be sufficiently exhibited, and if it exceeds 250 parts by weight, the workability and the adhesion will gradually decrease.

From this, the blending amount of the polyamide-imide resin (B) is 100
The amount is preferably from 20 to 100 parts by weight, particularly preferably from 30 to 70 parts by weight, based on parts by weight. Also,
The method of blending the polyamideimide resin is not particularly limited. For example, the polyamideimide resin may be N-methyl-2-
It can be blended as a resin solution dissolved in a polar solvent such as pyrrolidone or N, N-dimethylformamide and adjusted to an appropriate viscosity. The obtained heat-resistant resin composition can be used as a heat-resistant paint.

[0021]

Next, the present invention will be described in more detail by way of examples.

Example 1 185.01 g (1.4 equivalents) of 3,3'-dimethylbiphenyl-4,4'-diisocyanate [trade name TOD]
I Nippon Soda Co., Ltd.], 75.08 g (0.6 equivalent) of diphenylmethane-4,4'-diisocyanate, 192.13 g (2 equivalent) of trimellitic anhydride and N-methyl-
839.9 g of 2-pyrrolidone was charged into a 2 liter flask and heated to 125 ° C. in about 4 hours with stirring.
Incubating at this temperature for 6 hours, the number average molecular weight is 16,000.
Was obtained (resin concentration: 30).
% By weight, polyamide-imide resin solution-A).

Next, 254.01 g (2.03 equivalents) of diphenylmethane-4,4'-diisocyanate, 192.13 g (2 equivalents) of trimellitic anhydride and 669.21 g of N-methyl-2-pyrrolidone were added to 2 liters. The mixture was charged into a flask and heated to 135 ° C. in about 3 hours with stirring, and kept at this temperature for 7 hours to reduce the number average molecular weight to 2250.
0 was obtained (resin concentration: 3).
3%, polyamide-imide resin solution-B). A paint was obtained by adding 31.8 parts by weight of the polyamide-imide resin solution-B to 100 parts by weight of the obtained polyamide-imide resin solution-A.

Example 2 211.44 g (1.6 equivalents) of 3,3'-dimethylbiphenyl-4,4'-diisocyanate (trade name: TOD)
I Nippon Soda Co., Ltd.], diphenylmethane-4,4'-
50.05 g (0.4 equivalent) of diisocyanate, 172.92 g (1.8 equivalent) of trimellitic anhydride, 32.21 g (0.2 equivalent) of benzophenonetetracarboxylic dianhydride
Eq.) And N-methyl-2-pyrrolidone 1088.88.
g into a 2 liter flask and stir about 3
The temperature was raised to 130 ° C. over a period of time, and the temperature was kept at this temperature for 5 hours, and the polyamide-imide resin solution having a number average molecular weight of 14,200 (resin concentration: 25%, polyamide-imide resin solution—
A) was obtained.

Next, 200.21 g (1.6 equivalents) of diphenylmethane-4,4'-diisocyanate, 34.84 g (0.4 equivalents) of m-xylylene diisocyanate,
134.49 g (1.4 equivalents) of trimellitic anhydride, 88.26 g of biphenyltetracarboxylic dianhydride (0.
6 equivalents) and 686.7 g of N-methyl-2-pyrrolidone
Was charged into a 2 liter flask, and the temperature was raised to 125 ° C. in about 5 hours while stirring, and the temperature was maintained at this temperature for 5 hours to obtain a polyamideimide resin solution having a number average molecular weight of 17,600 (resin concentration: 30%, polyamideimide resin Solution-B) was obtained. Obtained polyamide-imide resin solution-A100
37.5 parts by weight of the polyamideimide resin solution-B was added to parts by weight to obtain a coating material.

Example 3 132.15 g (1.0 equivalent) of 3,3'-dimethylbiphenyl-4,4'-diisocyanate [TOD (trade name)
I Nippon Soda Co., Ltd.], diphenylmethane-4,4'-
125.13 g (1.0 equivalent) of diisocyanate, 192.13 g (2 equivalents) of trimellitic anhydride and 1048.61 g of N-methyl-2-pyrrolidone were charged into a 2 liter flask, and stirred at 125 ° C. for about 4 hours. And kept at this temperature for 9 hours to obtain a number average molecular weight of 23.
000 polyamideimide resin solution (resin concentration: 30% by weight, polyamideimide resin solution-A).

Next, 254.01 g (2.03 equivalents) of diphenylmethane-4,4'-diisocyanate, 192.13 g (2 equivalents) of trimellitic anhydride and 669.21 g of N-methyl-2-pyrrolidone were added to 2 liters. The mixture was charged into a flask and heated to 135 ° C. for about 3 hours with stirring, and kept at this temperature for 8 hours to give a number average molecular weight of 2500.
0 was obtained (resin concentration: 3).
3%, polyamide-imide resin solution-B). To 100 parts by weight of the obtained polyamide-imide resin solution-A, 60.0 parts by weight of the polyamide-imide resin solution-B was added to obtain a paint.

Comparative Example 1 Diphenylmethane-4,4'-diisocyanate 25
4.01 g (2.03 equivalents), trimellitic anhydride 19
2.13 g (2 equivalents) and 669.21 g of N-methyl-2-pyrrolidone were charged into a 2 liter flask, and the temperature was raised to 140 ° C. in about 3 hours while stirring.
The temperature was maintained for a period to obtain a polyamideimide resin solution having a number average molecular weight of 28,000 (resin concentration: 32%).

Comparative Example 2 185.01 g (1.4 equivalents) of 3,3'-dimethylbiphenyl-4,4'-diisocyanate [trade name TOD]
I Nippon Soda Co., Ltd.], diphenylmethane-4,4'-
75.08 g (0.6 equivalent) of diisocyanate, 192.13 g of trimellitic anhydride and 839.9 g of N-methyl-2-pyrrolidone were charged into a 2 liter flask,
The temperature was raised to 125 ° C. in about 4 hours with stirring, and the temperature was kept at this temperature for 6 hours to obtain a polyamideimide resin solution having a number average molecular weight of 16,000 (resin concentration: 30%).

Comparative Example 3 Polyamideimide Resin Solution-A1 Obtained in Example 1
A coating material was obtained by adding 7.3 parts by weight of the polyamideimide resin solution-B to 00 parts by weight.

Comparative Example 4 Polyamide-imide resin solution obtained in Example 1 -A 1
Polyamideimide resin solution-B 236.00 parts by weight.
4 parts by weight were added to obtain a paint.

Test Example The polyamide-imide resin-based heat-resistant resin composition or polyamide-imide resin solution obtained in Examples 1 to 3 and Comparative Examples 1 to 4 was used as a base material (aluminum base material J JISH400).
0, unpolished product, t = 0.5 mm, acetone degreasing treatment), then cured at 350 ° C. for 30 minutes to obtain a coating thickness of about 1
Produce a 0μm coated plate, and adherence and workability (bendability)
Was tested.

[0033]

[Table 1]

As shown in FIG. 1, the spacer 3 is sandwiched between
The presence or absence of minute cracks generated in the coating film on the substrate 2 when bent at 180 degrees was observed and judged by magnifying 10 times with a magnifying glass. The test was conducted by changing the thickness of the spacer, and it was described how many times the minimum thickness of the spacer that did not cause microcracks was larger than the thickness of the substrate.

[0035]

[Table 2] In the case of the above result, it was determined to be 2T.

From Table 1, it can be seen that the coating films obtained from the polyamide-imide resin-based heat-resistant resin compositions of Examples 1 to 3 show Comparative Example 1
4 shows that the adhesiveness and workability after curing at a high temperature (350 ° C.) are superior to those of the coating films obtained from Nos. 4 to 4.

[0037]

The coating composition using the polyamide-imide resin-based heat-resistant resin composition of the present invention as a coating film component has excellent heat resistance, adhesion, and processability when cured at a high temperature of 350 ° C. or higher. The film can be formed and is useful as an insulating film on various substrates, a protective coat, and the like. In particular, it can be expected to be applied to high heat-resistant applications for precoating.

[Brief description of the drawings]

FIG. 1 Test method for workability (bendability) of coating film (T-vent method)
It is a schematic diagram explaining.

[Explanation of symbols]

 1 Coating 2 Substrate 3 Spacer

Continued on the front page F-term (reference) 4J002 CM04W CM04X GH01 HA05 4J038 DJ051 MA14 NA04 NA12 NA14 NA23 PA19 PB09 PC02 4J043 PA04 PA08 PC015 PC016 PC115 PC116 PC135 PC136 QB58 RA05 RA34 SA11 SB02 SB03 TA11 TA13 TA21 TA25 TB01 UA1220131 VA062 XA19 ZB01

Claims (4)

[Claims] 1. A compound of the general formula (I) (Wherein R ¹ and R ² independently represent a hydrogen atom, an alkyl group,
Which is obtained by reacting an aromatic diisocyanate component represented by an alkoxy group or a halogen atom) with trihydrochloric acid anhydride, represented by the general formula (II): (Wherein R ¹ and R ² independently represent a hydrogen atom, an alkyl group,
An alkoxy group or a halogen atom, R ³ represents a trivalent organic group), and 100 parts by weight of a polyamideimide resin (A) having a repeating unit represented by the following formula: General formula (II) obtained by reacting anhydrous trihydrochloric acid with
I) (Wherein, R ³ represents a trivalent organic group, and R ⁴ represents a divalent organic group). Resin composition. 2. The content of the aromatic diisocyanate represented by the general formula (I) in the total diisocyanate component as a raw material of the polyamide-imide resin (A) is from 20 to 90.
The heat-resistant resin composition according to claim 1, which is an equivalent%. 3. The heat-resistant resin composition according to claim 1, wherein the polyamide-imide resin (B) has a number average molecular weight of 10,000 to 50,000. 4. A paint containing the heat-resistant resin composition according to claim 1 as a coating film component.