Halogen-free flame-retardant metallized film capacitor

Abstract

The invention relates to a halogen-free flame-retardant metallized film capacitor which comprises an aluminum shell, a capacitor core located in the aluminum shell and a resin packaging layer used for carrying out insulation packaging on the capacitor core, the resin packaging layer is prepared by curing benzoxazine resin glue, and the benzoxazine resin glue is prepared by mixing 100 parts by mass of 4, 4 '-dibenzoxazine with 100 parts by mass of 4, 4'-dibenzoxazine. The material is prepared by uniformly mixing 20-25 parts by mass of 4, 4 '-diaminodiphenylmethane benzoxazine, 20-25 parts by mass of a curing agent, 0.5-0.7 part by mass of an accelerant, 15-20 parts by mass of filler, 3.5-5 parts by mass of a flame retardant and 100-150 parts by mass of a solvent. The halogen-free flame-retardant metallized film capacitor meets the halogen-free requirement, and is good in flame retardance, very low in total smoke release amount and high in heat resistance.

Description

Technical Field

[0001] The present invention and the field of film capacitors specifically relate to a halogen-free flame-retardant metallized film capacitor. Background Art

[0002] Film capacitors are also called plastic film capacitors, which use plastic film as dielectric.

[0003] The structure of an existing film capacitor generally includes a capacitor housing, a capacitor core, and an epoxy resin encapsulation layer used to completely encapsulate the capacitor core. The epoxy resin encapsulation layer used is generally made of epoxy resin adhesive doped with fillers (such as spherical alumina) and then cured.

[0004] However, the existing epoxy resin has poor flame retardancy and low heat resistance, and generally cannot reach V0 flame retardancy (UL94 standard). A large amount of brominated flame retardants need to be added, but brominated flame retardants do not meet environmental protection requirements. In addition, a large amount of brominated flame retardants will also cause the heat resistance to deteriorate. This is a problem that needs to be solved urgently for large-capacity energy storage capacitors. Summary of the invention

[0005] The specific technical solutions of the present invention are as follows:

[0006] A halogen-free flame-retardant metallized film capacitor comprises an aluminum shell, a capacitor core in the aluminum shell, and a resin packaging layer for insulating and packaging the capacitor core. The resin packaging layer is made of a benzoxazine resin adhesive that is cured. The benzoxazine resin adhesive is made by uniformly mixing a benzoxazine resin, a curing agent, an accelerator, a filler, a flame retardant, and a solvent.

[0007] In an optional embodiment, the benzoxazine resin glue is prepared by uniformly mixing 100 parts by mass of benzoxazine resin, 20 to 25 parts by mass of curing agent, 0.5 to 0.7 parts by mass of accelerator, 15 to 20 parts by mass of filler, 3.5 to 5 parts by mass of flame retardant and 100 to 150 parts by mass of solvent.

[0008] In an optional embodiment, the benzoxazine resin is 4,4'-diaminodiphenylmethane type benzoxazine, and its structural formula is shown in Formula 1:

[0009]

[0010] In an optional embodiment, the curing agent is one or more of 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, and dicyandiamide.

[0011] In an optional embodiment, the accelerator is 2-methylimidazole or 2-phenylimidazole.

[0012] In an optional embodiment, the filler is one or more of magnesium hydroxide, aluminum hydroxide, aluminum oxide, aluminum nitride, silicon dioxide, and silicon powder.

[0013] In an optional embodiment, the solvent is one or more of acetone, butanone, N,N-dimethylformamide, propylene glycol monomethyl ether, toluene, and xylene.

[0014] In an optional embodiment, the flame retardant is aminotrimethylenephosphonic acid or alkyl phosphinate aluminum.

[0015] In an optional embodiment, the curing agent is prepared by mixing 4,4'-diaminodiphenyl sulfone and dicyandiamide in a mass ratio of 10:3, and the flame retardant is aminotrimethylenephosphonic acid.

[0016] In the present invention, the halogen-free flame-retardant metallized film capacitor meets the halogen-free requirement, has good flame retardancy, has very low total smoke emission, and has high heat resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the trend chart of x value and total smoke release;

[0018] Figure 2 This is a trend chart of the dosage of flame retardant aminotrimethylenephosphonic acid and the Tg value;

[0019] Figure 3 This is a physical photo of the halogen-free flame-retardant metallized film capacitor described in Example 1. DETAILED DESCRIPTION

[0020] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments.

[0021] Example 1

[0022] A halogen-free flame-retardant metallized film capacitor comprises an aluminum shell, a capacitor core in the aluminum shell, and a resin packaging layer for insulating and packaging the capacitor core, wherein the resin packaging layer is made by curing a benzoxazine resin adhesive, wherein the benzoxazine resin adhesive is made by uniformly mixing 1000 g of benzoxazine resin, 200 g of a curing agent, 5 g of an accelerator, 150 g of a filler, 35 g of a flame retardant, and 1000 g of a solvent.

[0023] The benzoxazine resin is 4,4'-diaminodiphenylmethane type benzoxazine, and its structural formula is as follows

[0024] As shown in formula 1:

[0025]

[0026] The curing agent is prepared by mixing 4,4'-diaminodiphenyl sulfone and dicyandiamide in a mass ratio of 10:3, the flame retardant is aminotrimethylenephosphonic acid, the accelerator is 2-methylimidazole, the filler is aluminum oxide, and the solvent is propylene glycol monomethyl ether.

[0027] The actual halogen-free flame-retardant metallized film capacitor described in this example can be found at Figure 3 .

[0028] Example 2

[0029] A halogen-free flame-retardant metallized film capacitor comprises an aluminum shell, a capacitor core in the aluminum shell, and a resin packaging layer for insulating and packaging the capacitor core, wherein the resin packaging layer is made by curing a benzoxazine resin adhesive, wherein the benzoxazine resin adhesive is made by uniformly mixing 1000 g of benzoxazine resin, 220 g of a curing agent, 6 g of an accelerator, 160 g of a filler, 40 g of a flame retardant, and 1200 g of a solvent.

[0030] The benzoxazine resin is 4,4'-diaminodiphenylmethane type benzoxazine, and its structural formula is shown in Formula 1.

[0031] The curing agent is prepared by mixing 4,4'-diaminodiphenyl sulfone and dicyandiamide in a mass ratio of 10:3, the flame retardant is aminotrimethylenephosphonic acid, the accelerator is 2-methylimidazole, the filler is aluminum oxide, and the solvent is propylene glycol monomethyl ether.

[0032] Example 3

[0033] A halogen-free flame-retardant metallized film capacitor comprises an aluminum shell, a capacitor core in the aluminum shell, and a resin packaging layer for insulating and packaging the capacitor core, wherein the resin packaging layer is made by curing a benzoxazine resin adhesive, wherein the benzoxazine resin adhesive is made by uniformly mixing 1000 g of benzoxazine resin, 250 g of a curing agent, 7 g of an accelerator, 200 g of a filler, 50 g of a flame retardant, and 1500 g of a solvent.

[0034] The benzoxazine resin is 4,4'-diaminodiphenylmethane type benzoxazine, and its structural formula is shown in Formula 1.

[0035] The curing agent is prepared by mixing 4,4'-diaminodiphenyl sulfone and dicyandiamide in a mass ratio of 10:3, the flame retardant is aminotrimethylenephosphonic acid, the accelerator is 2-methylimidazole, the filler is aluminum oxide, and the solvent is propylene glycol monomethyl ether.

[0036] Comparative Example 1

[0037] In this example, the curing agent is 4,4'-diaminodiphenyl sulfone, and the rest is the same as in Example 2.

[0038] Comparative Example 2

[0039] In this example, the curing agent is dicyandiamide, and the rest is the same as in Example 2.

[0040] Comparative Example 3

[0041] In this example, the benzoxazine resin is bisphenol A type benzoxazine resin, and the rest is the same as in Example 2.

[0042] Comparative Example 4

[0043] In this example, the benzoxazine resin is a DOPO type benzoxazine resin, and the rest is the same as in Example 2.

[0044] Comparative Example 5

[0045] In this example, the flame retardant is alkyl aluminum phosphinate, and the rest is the same as in Example 2.

[0046] Comparative Example 6

[0047] In this example, the flame retardant is melamine polyphosphate (CAS No. 15541-60-3), and the rest is the same as Example 2.

[0048] The test results of the resin encapsulation layer performance in Examples 1 to 3 and Comparative Examples 1 to 6 are shown in Table 1:

[0049] Table 1

[0050] UL94 flame retardant performance Heat resistance Tg(℃) <![CDATA[Total flue gas emission (m 2 )]]> Example 1 V0 210 13.05 Example 2 V0 205 12.98 Example 3 V0 208 13.77 Comparative Example 1 V0 203 28.71 Comparative Example 2 V0 188 30.65 Comparative Example 3 V1 175 / Comparative Example 4 V1 158 / Comparative Example 5 V0 209 25.68 Comparative Example 6 V0 203 33.01

[0051] From the above, it can be seen that the use of 4,4'-diaminodiphenylmethane type benzoxazine has high heat resistance and is suitable for the capacitor field. In addition, the curing agent is a combination of 4,4'-diaminodiphenyl sulfone and dicyandiamide, which can significantly improve the flame retardant effect of the flame retardant aminotrimethylenephosphonic acid, especially the smoke suppression effect.

[0052] Comparative Example 7

[0053] The curing agent is prepared by mixing 4,4'-diaminodiphenyl sulfone and dicyandiamide in a mass ratio of 10:x, and the rest is the same as Example 2. When x varies in the range of 0.5 to 7, the corresponding total smoke emission variation trend is shown in FIG. Figure 1 .Depend on Figure 1 It can be seen that x is preferably 3.

[0054] Comparative Example 8

[0055] In the experiment, it was found that as the amount of flame retardant aminotrimethylenephosphonic acid (ratio of aminotrimethylenephosphonic acid to 4,4'-diaminodiphenylmethane benzoxazine) increased, the flame retardant performance reached the limit (V0, total smoke emission was between 12.5 and 13.8 m 2 No less than 12.5m 2 ), but the higher the amount of flame retardant aminotrimethylenephosphonic acid added, the lower the Tg value will be. The trend of change is shown in Figure 2 .

[0056] Depend on Figure 2 It can be seen that, considering flame retardancy and heat resistance, preferably, the blending amount of the flame retardant aminotrimethylenephosphonic acid is 3.5% to 5%.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A halogen-free flame-retardant metallized film capacitor, comprising an aluminum shell, a capacitor core in the aluminum shell, and a resin encapsulation layer for insulating and encapsulating the capacitor core, characterized in that: The resin encapsulation layer is made of a benzoxazine resin adhesive through curing, and the benzoxazine resin adhesive is made by uniformly mixing a benzoxazine resin, a curing agent, an accelerator, a filler, a flame retardant and a solvent.

2. The halogen-free flame-retardant metallized film capacitor according to claim 1, characterized in that: The benzoxazine resin adhesive is prepared by uniformly mixing 100 parts by mass of benzoxazine resin, 20 to 25 parts by mass of curing agent, 0.5 to 0.7 parts by mass of accelerator, 15 to 20 parts by mass of filler, 3.5 to 5 parts by mass of flame retardant and 100 to 150 parts by mass of solvent.

3. The halogen-free flame-retardant metallized film capacitor according to claim 1, characterized in that: The benzoxazine resin is 4,4'-diaminodiphenylmethane type benzoxazine, and its structural formula is shown in Formula 1:

4. The halogen-free flame-retardant metallized film capacitor according to claim 1, characterized in that: The curing agent is one or more of 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether and dicyandiamide.

5. The halogen-free flame-retardant metallized film capacitor according to claim 1, characterized in that: The accelerator is 2-methylimidazole or 2-phenylimidazole.

6. The halogen-free flame-retardant metallized film capacitor according to claim 1, characterized in that: The filler is one or more of magnesium hydroxide, aluminum hydroxide, aluminum oxide, aluminum nitride, silicon dioxide, and silicon powder.

7. The halogen-free flame-retardant metallized film capacitor according to claim 1, characterized in that: The solvent is one or more of acetone, butanone, N,N-dimethylformamide, propylene glycol monomethyl ether, toluene and xylene.

8. The halogen-free flame-retardant metallized film capacitor according to claim 1, characterized in that: The flame retardant is aminotrimethylenephosphonic acid or alkylphosphinate aluminum.

9. The halogen-free flame-retardant metallized film capacitor according to claim 1, characterized in that: The curing agent is prepared by mixing 4,4'-diaminodiphenyl sulfone and dicyandiamide in a mass ratio of 10:3, and the flame retardant is aminotrimethylenephosphonic acid.

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