阅读说明：本技术 用于高电压应用的混合树脂 (Hybrid resins for high voltage applications ) 是由 R·格特 N·赫西 M·费拉里斯 P·盖拉尔迪 N·库米内蒂 M·维奥拉 D·瓦因斯 于 2019-10-04 设计创作，主要内容包括：本发明涉及包含基于环氧和酯的树脂、反应性稀释剂以及自由基聚合引发剂的组合物。此外,本发明涉及提供此类组合物的方法、施加该组合物的方法、使用该组合物作为涂布材料的用途、以及涂有聚合的组合物的材料。(The present invention relates to compositions comprising epoxy and ester based resins, a reactive diluent, and a free radical polymerization initiator. Furthermore, the present invention relates to a method of providing such a composition, a method of applying the composition, the use of the composition as a coating material, and a material coated with the polymerized composition.)

1. A composition comprising:

A) a resin component comprising:

i. one or more identical or different radicals of the formula

Wherein R is an organic group comprising 2 to 40 carbon atoms;

one or more groups comprising two ester groups and one ethylenically unsaturated group;

one or more terminal or pendant groups comprising one ester group and one ethylenically unsaturated group;

B) at least one reactive diluent having at least one ethylenically unsaturated polymerizable group and having a boiling point at atmospheric pressure above 200 ℃; and

C) a radical polymerization initiator;

wherein the resin component A has an acid value of not more than 50 mgKOH/g.

2. The composition of claim 1, wherein R comprises a hydrocarbon portion of bisphenol A or bisphenol F units.

3. The composition of claim 1 or 2, wherein the side groups or end groups iii.

4. The composition of any of claims 1 to 3, wherein group ii.

5. The composition of any of claims 1 to 4, wherein component A is the reaction product of

A1) An epoxy resin;

A2) a compound comprising a) two carboxylic acid groups or carboxylic anhydride groups and b) one ethylenically unsaturated group, and

A3) a compound having one carboxylic acid group and one ethylenically unsaturated group.

6. The composition of claim 5 wherein the epoxy resin of component A1 further comprises bisphenol A and/or F units.

7. A composition as claimed in any one of claims 5 to 6, wherein component A3) is selected from acrylic acid, methacrylic acid and mixtures thereof.

8. A composition according to any of claims 5 to 7 wherein component A2 is selected from fumaric acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride and mixtures thereof.

9. The composition of any of claims 1 to 8, wherein component B is present in an amount of 20 to 70 weight percent, based on the total weight of the composition.

10. The composition of claim 1, wherein the composition has a viscosity of 50 to 450cP at a temperature of 25 ℃.

11. A method of preparing a treated metal-containing substrate comprising the steps of:

a. providing a composition according to any one of the preceding claims;

b. applying the composition to a substrate comprising a metal; and are

c. Polymerizing the composition.

12. The method of claim 11, wherein the metal-containing substrate further comprises tape.

13. A treated metal-containing substrate obtainable by the process of claim 11 or 12.

14. A process for preparing a composition according to any one of claims 1 to 10, comprising the steps of:

a. providing a1) an epoxy resin, A3) a compound having one carboxylic acid group and one ethylenically unsaturated group, and a catalyst, optionally in the presence of one or more free radical polymerization inhibitors, in a reactor to obtain a mixture;

b. reacting the mixture of step a. to obtain a first reaction product until the acid value of the first reaction product is less than 50 mgKOH/g;

c. providing in a reactor a2) a compound comprising a) two carboxylic acid groups or carboxylic acid anhydride groups and b) one ethylenically unsaturated group;

d. further reacting the mixture of steps a.to c.to obtain a second reaction product until the acid value of the second reaction product is less than 50 mgKOH/g;

e. to component a are added components B and C and optionally further components.

15. Use of a composition according to any one of claims 1 to 10 for coating and/or impregnating a metal-containing substrate.

16. Use of the treated substrate of claim 13 for electrical insulation.

Background

The present invention relates to compositions for use as insulators in electrical machines, such as rotating and non-rotating electrical machines.

In electrical machines, especially those that are subjected to high voltages, the insulating material used for the coils is of paramount importance for its performance and service life.

Common insulating materials are organic thermosetting polymers whose thermal, electrical, chemical and mechanical properties are key requirements for obtaining long-term performance of the machine.

US 2012/0259039 discloses a resin composition for fibre-reinforced composites comprising an epoxy resin, a free-radically polymerizable monomer containing an acid group (such as acrylic or methacrylic acid) and an amine-based curing agent for the epoxy resin.

US 2015/0306790 discloses a process for the manufacture of storage stable epoxy prepregs (preprg) using at least one reactive resin having at least one acid group and at least one epoxy-based reactive resin component, wherein one or both of the reactive resins comprises a group capable of free radical polymerisation, and composites made by this process.

US 6,555,023 and US 6,680,119 disclose insulated electrical coils, the insulation of which is formed from a cured resin composition of an epoxy-anhydride resin that has been pre-reacted with an antioxidant oligomer selected from the group consisting of organic phosphorus compounds, phenolics (phenolics), thioesters, thiophosphites, thiazoles, lactones, hydroxylamines and maleimides.

Epoxy resins cured with anhydrides, for example, have a higher viscosity, which is disadvantageous during impregnation. Anhydrides also have potential health hazards and are sensitive to moisture. Unsaturated polyester resins have been used to obtain low viscosity solutions for easy penetration of the mica tapes, but low viscosity solutions lead to poor mechanical, thermal and/or chemical resistance. Styrene or vinyl toluene reactive diluents are also potentially toxic and flammable.

Thus, there is a need to find new materials suitable for impregnation and/or coating, which have a low viscosity and still have good mechanical, thermal and/or chemical properties, in particular for use as insulators in electrical machines.

These problems are solved by the composition of the present invention comprising a resin component, a reactive diluent and a free radical polymerization initiator.

One of the advantages of the composition of the present invention is that it provides a curing system that does not contain anhydrides as curing agents. In addition, the use of styrene or vinyl toluene can be significantly reduced or avoided.

In general, the compositions of the invention combine the advantage of having a low viscosity (which is essential for applying them to a substrate), while the polymers obtained after curing the compositions have good mechanical, thermal and chemical properties.

In other aspects, the invention relates to methods of making and methods of applying the compositions of the invention.

The invention also relates to the use of the composition according to the invention as a coating on a substrate, in particular as an insulation material for applications in electrical machines.

Detailed Description

In a first embodiment, the present invention relates to a composition comprising:

A) a resin component comprising:

i. one or more identical or different radicals of the formula

Wherein R is an organic group having 2 to 40 carbon atoms;

one or more groups comprising two ester groups and one ethylenically unsaturated group;

one or more terminal or pendant groups comprising one ester group and one ethylenically unsaturated group;

B) at least one reactive diluent having at least one ethylenically unsaturated polymerizable group and having a boiling point at atmospheric pressure above 200 ℃; and

C) a radical polymerization initiator.

In another embodiment, the present invention relates to a composition comprising:

A) a resin component comprising:

i. one or more identical or different radicals of the formula

Wherein R is an organic group comprising 2 to 40 carbon atoms;

one or more groups comprising two ester groups and one ethylenically unsaturated group;

one or more terminal or pendant groups comprising one ester group and one ethylenically unsaturated group;

B) at least one reactive diluent having at least one ethylenically unsaturated polymerizable group and having a boiling point at atmospheric pressure above 200 ℃; and

C) a radical polymerization initiator.

Wherein the resin component A has an acid value of not more than 50 mgKOH/g. Within the meaning of the present invention, R is an organic group comprising 2 to 40 carbon atoms, wherein the organic group comprises at least an aromatic group, an aliphatic group, a heteroaromatic group, a heteroaliphatic group or mixtures thereof. The aliphatic group may be linear, branched, cyclic, or mixtures thereof.

In a further preferred embodiment, R comprises the hydrocarbon portion of a bisphenol A or bisphenol F unit.

Within the meaning of the present invention, brackets [ ] denote the point of attachment of the group shown in brackets to the rest of the molecule.

In another preferred embodiment, in the composition of the present invention, the side group or end group iii.

Preferably, the ethylenically unsaturated group is a conjugated ethylenically unsaturated group.

In the context of a compound or composition, the use of "consisting essentially of … …" or "consisting essentially of" means that certain other components, i.e., those components that do not materially affect the essential characteristics of the compound or composition, may be present.

In some embodiments, the resin component a comprises 90 wt.%, preferably 95 wt.%, more preferably 98 wt.% of the groups i), ii) and iii) present in the resin component a, calculated on the total weight of the resin component a.

In some embodiments, resin component a of the compositions of the present invention consists essentially of:

i. one or more identical or different radicals of the formula

Wherein R is an organic group containing 2 to 40 carbon atoms

One or more groups comprising two ester groups and one ethylenically unsaturated group;

one or more terminal or pendant groups comprising one ester group and one ethylenically unsaturated group.

In another preferred embodiment, in the composition of the invention, the group ii.

In another preferred embodiment, in the composition of the invention, component A is the reaction product of

A1) An epoxy resin;

A2) compounds comprising a) two carboxylic acid groups or carboxylic anhydride groups (a) two carboxylic acid groups or a carboxylic acid anhydride group) and b) one ethylenically unsaturated group, with

A3) A compound having one carboxylic acid group and one ethylenically unsaturated group.

In a further preferred embodiment of the present invention, the epoxy resin of component a1 further comprises bisphenol a and/or F units.

In a further preferred embodiment of the present invention, component a3) is selected from acrylic acid, methacrylic acid and mixtures thereof.

In a further preferred embodiment of the present invention, component a2 is selected from fumaric acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride and mixtures thereof. Most preferably, component a2 is selected from fumaric acid, maleic acid and maleic anhydride.

In a further preferred embodiment, component A of the composition of the invention has an acid number of at most 50mgKOH/g, preferably component A of the composition of the invention has an acid number of at most 40mgKOH/g, more preferably component A of the composition of the invention has an acid number of at most 30mgKOH/g, most preferably component A of the composition of the invention has an acid number of at most 20 mgKOH/g.

Preferably, component A of the composition of the invention has an acid value of from 0 to 50mgKOH/g, preferably from 1 to 50mgKOH/g, more preferably component A of the composition of the invention has an acid value of from 0 to 40mgKOH/g, preferably from 1 to 40 mgKOH/g. More preferably, component A of the composition of the invention has an acid number of from 0 to 30mgKOH/g, preferably from 1 to 30 mgKOH/g. Most preferably, component A of the composition of the present invention has an acid value of from 0 to 20mgKOH/g, preferably from 1 to 20 mgKOH/g.

In a further preferred embodiment, component B of the composition of the invention is liquid at a temperature of 25 ℃.

In a further preferred embodiment, component B of the composition of the present invention comprises up to 3% by weight, based on the total weight of the composition, of a styrene and/or vinyltoluene reactive diluent. More preferably, component B of the composition does not contain a styrene and/or vinyl toluene reactive diluent.

In a further preferred embodiment, component B of the composition of the present invention is present in an amount of from 20 to 70% by weight, calculated on the total weight of the composition. In a more preferred embodiment, component B of the composition is present in an amount of from 30 to 70 wt.%, more preferably from 40 to 60 wt.%, more preferably from 40 to 55 wt.%, calculated on the total weight of the composition.

In a further preferred embodiment, the composition of the invention is substantially free of epoxy groups.

In a further preferred embodiment, the composition of the invention has a viscosity of 50 to 450mPa s at a temperature of 25 ℃. More preferably, the composition of the invention has a viscosity of from 100 to 450mPa s at a temperature of 25 ℃, more preferably from 150 to 450mPa s at a temperature of 25 ℃.

In another embodiment, the present invention relates to a method of preparing a treated metal-containing substrate comprising the steps of:

a. providing a composition of the invention;

b. applying the composition to a substrate comprising a metal; and are

c. Polymerizing the composition.

Within the meaning of the present invention, step c. In fact, in this step, the ethylenically unsaturated groups of the resin of the composition of the invention are polymerized at a suitable temperature to effect free-radical polymerization in the presence of a catalyst suitable for free-radical polymerization, such as a peroxide.

In another preferred embodiment, the metal-containing substrate further comprises tape, preferably mica tape.

Typically, the tape is wound on the substrate surface. Mica tape means that the tape contains mica. Any type of tape that is typically used to insulate metal rods or substrates used in electrical machines is a suitable tape in accordance with the present invention.

In another embodiment, the invention relates to a treated metal-containing substrate obtainable by the process of preparing a treated substrate, preferably the treated substrate further comprises tape, more preferably mica tape.

Within the meaning of the present invention, the metal-containing substrate is an electrical conductor. The metal may be copper, aluminum, iron, gold, or other alloys for electromechanical devices. The substrate is not limited to metal-containing rods, but is also understood to include one or more electrical conductors, such as wires or coils, wherein the wires or coils may or may not be pre-coated. The electrical conductor or the substrate may be at least partially coated on the metal surface, or other materials may be applied on the metal surface, or even another form of insulating material, such as the aforementioned tape, may be applied on the electrical conductor or the substrate.

Optionally, the metal containing substrate is wrapped with mica tape for dielectric breakdown protection. The mica tape is most effective in protecting against dielectric breakdown when the air gaps and moisture are replaced by the impregnating material (i.e. the composition of the invention) by a vacuum pressure impregnation procedure.

In another embodiment, the present invention relates to a method of making the composition of the present invention comprising the steps of:

a. providing component a1) an epoxy resin, component A3) a compound having one carboxylic acid group and one ethylenically unsaturated group, and a catalyst, optionally in the presence of one or more free radical polymerization inhibitors, in a reactor to obtain a mixture;

b. reacting the mixture of step a. to obtain a first reaction product until the acid value of the first reaction product is less than 50 mgKOH/g;

c. providing component A2) a compound comprising a) two carboxylic acid groups or carboxylic anhydride groups (a) two carboxylic acid groups or a carboxylic acid anhydride group) and b) one ethylenically unsaturated group in a reactor;

d. further reacting the mixture of steps a.to c.to obtain a second reaction product until the acid value of the second reaction product is less than 50 mgKOH/g;

e. adding other components to the second reaction product.

According to the invention, the second reaction product yields component a of the composition of the invention, and preferably the other components added to component a are components B and C of the composition of the invention.

In a further preferred embodiment of the process for preparing the composition of the invention, the acid value of the first reaction product and the acid value of the second reaction product may be the same or different and is at most 50mgKOH/g, preferably it is at most 40mgKOH/g, more preferably it is at most 30mgKOH/g, most preferably it is at most 20 mgKOH/g.

The above-defined ranges for the acid number of the resin component a also apply to the reaction product of the process.

The advantage of a lower acid number is better solubility in the monomer.

In another embodiment, the present invention relates to the use of the composition of the present invention for coating and/or impregnating a substrate.

Preferably, the composition is used for coating and/or impregnating an electrical machine, more preferably a high voltage electrical machine.

In another embodiment, the invention relates to the use of the treated substrate for electrical insulation, preferably in an electrical machine.

Within the meaning of the present invention, a reactive diluent is a diluent having at least one ethylenically unsaturated polymerizable group and a boiling point of more than 200 ℃. Non-limiting examples of reactive diluents include vinyl ethers, acrylates, methacrylates, allyl groups, olefins (and vinyls).

Preferably, the reactive diluent of the present invention has at least two ethylenically unsaturated polymerizable groups. Most preferably, the reactive diluent of the present invention has two ethylenically unsaturated polymerizable groups.

The most preferred reactive diluents are diallyl fumarate (DAF), tetraethylene glycol di (meth) acrylate (TEGDMA), hexanediol di (meth) acrylate (HDDMA), butanediol dimethacrylate or mixtures thereof.

Within the meaning of the present invention, epoxy resins or epoxy-type resins are those resins which bear at least one epoxy group, preferably at least two epoxy groups, per molecule. Preferred epoxy resins of the present invention comprise one or more epoxy groups and bisphenol a or bisphenol F or a mixture of bisphenol a and F.

In a preferred embodiment, the composition is substantially free of epoxy groups. Substantially free of epoxy groups also encompasses free of epoxy groups and means that the material has an epoxy equivalent weight (epoxide equivalent weight) of at least 2000g/eq, preferably at least 3000g/ep, more preferably at least 4000g/eq, most preferably at least 5000 g/eq.

Free-radical polymerization initiators within the meaning of the present invention are compounds which are suitable for initiating free-radical polymerization. The preferred free radical polymerization initiator is a peroxide. Dicumyl peroxide is most preferred.

Within the meaning of the present invention, applying the composition of the present invention on a substrate means that the substrate can be coated and/or impregnated with the composition of the present invention.

A coating is a covering applied to the surface of a substrate, wherein the coating itself may be a full-scale coating, i.e. completely covering the substrate, or it may only cover a portion of the substrate.

The substrate is impregnated when it at least partially absorbs liquid, in this case the composition used to impregnate the substrate. This means that the cavities or voids present in the substrate are at least partially covered by the composition of the invention.

Examples

Measuring

Examples 1 to 11

1. Preparation of reactive compositions

A glass reactor equipped with a water-cooled condenser was used for the synthesis of the resin. A combination of nitrogen and air was bubbled into the reactor. Bisphenol F or bisphenol a type epoxy resin (Epon 824, 344 g) and inhibitor were added to the reactor and the stirring was turned on. Glacial acrylic or methacrylic acid (140 g) and Ancamine K54(0.6 g) catalyst were then added to the vessel and the reaction mixture was heated to 99 ℃. An exotherm was observed which increased the reaction temperature to about 121 ℃. The solution was then maintained at 104 ℃ and 110 ℃ until the acid number was reduced to less than 20mg KOH/g of reaction product. The material was then cooled to below 82 ℃ and maleic anhydride (22 g) was added. The reaction temperature was then increased to 104.4-110 ℃ until an acid number of less than 20mg KOH per gram of reaction product was reached. The reaction was then divided into multiple samples, which were allowed to cool to room temperature. The reaction product is then re-melted, additional inhibitor added, and diluted with diallyl fumarate (DAF, 415 g), tetraethylene glycol di (meth) acrylate (TEGDMA, 507 g), hexanediol di (meth) acrylate (HDDMA, 507 g), or butanediol dimethacrylate (BDDMA, 507 g) monomer until a viscosity of about 400cP or less is obtained. The material was then cooled to below 49 ℃ and dicumyl peroxide (5-20 g) was added. Finally, the material was filtered through a 25 micron cloth. The chemical compositions of examples 1-11 are detailed in table 1.

TABLE 1

TABLE 2 physical Properties

TABLE 3 mechanical Properties

TABLE 4 dielectric constant (Electrical resistivity) at different temperatures

TABLE 5 Dissipation Factor at different temperatures

TABLE 6 Dielectric Strength before and after Water immersion (Dielectric Strength)

Description of Material Properties

Table 2 shows details of the physical properties of each sample.

The viscosity of the compositions of examples 1 to 11 was below 450 mPas.

Sunlight (SS) gel is a measure of reactivity and can be used for the desired curing procedure.

The glass transition temperature (Tg) was measured on the cured material using a Modulated Differential Scanning Calorimeter (MDSC). The Tg ranges from 69 ℃ to 153 ℃ depending on the reactive diluent used.

Mechanical properties were examined by bond strength (bond strength) using a spiral coil of MW35 magnet wire.

As shown in table 3, the cured resin of the present invention exhibited good mechanical resistance. After a temperature increase of 125 c (from 25 c to 150 c), the adhesive strength decreases by only about 50% of the value observed at 25 c, and still maintains good values, especially for such high temperatures of 150 c.

The electrical properties of the resins are shown in tables 4-6.

Dielectric strength represents the maximum voltage a material can withstand, depending on its thickness. This value was measured before and after soaking in water. As shown in table 6, the dielectric strength was not affected by water immersion, and in some cases, the property was improved after water immersion, which was unexpected.

All samples showed excellent electrical properties as the dissipation factor of all samples remained below 0.1 up to 150 ℃. The closer the dissipation factor is to zero, the less energy is lost in the insulation.

Dielectric constants (also referred to as dielectric constants) measured at various temperatures in the range of 25 ℃ to 200 ℃ are shown in table 4. Small changes in dielectric constant are an important feature of high voltage systems to avoid charge concentrations that can cause damage over long periods of use.

Table 5 relates to the measurement of dissipation factor, which represents the amount of energy lost in the insulation material. A constant and low dissipation factor at a certain temperature is crucial for making a good high voltage insulation system; a value of 0.1 at high temperatures (e.g. above 150 ℃) is generally considered as a threshold value.

Method

The above-mentioned properties were measured according to the following methods.

Acid value

The acid number is the amount of KOH in mg required to neutralize 1 g of material under defined conditions. The acid number is determined by neutralization according to DIN EN ISO 2114 with 0.1N KOH in ethanol.

The viscosity was measured according to ISO 3219 using a Brookfield LV viscometer at 25 ℃ using a spindle number 6 and 25 rpm.

Dissipation factor and dielectric constant (DF/DC) were measured simultaneously according to ASTM D150, and samples were cast in small capacitors.

The adhesive strength was measured on impregnated spiral coils according to ASTM D2519.

Dielectric strength was measured on steel plates coated with resin samples according to ASTM D149.

GPC measurements were performed using Agilent Infinity 1260 GPC. The Infinity GPC was equipped with an Infinity 1260 degasser. The Infinity GPC is equipped with an isocratic pump (isocratic pump), also model number Infinity 1260. The sequence number is DEAB 902598. The Infinity GPC, in turn, contains accessories for the constant temperature GPC column and autosampler functions. The solvent was Tetrahydrofuran (THF) supplied by Honeywell. The purity is 99.9 percent, and the peroxide content is less than 2 mg/L. The sample to be analyzed is first dissolved in THF with gentle stirring. The sample was then filtered through a 5 ml syringe with a 0.5 micron filter housing. The solution was collected in a 5 ml vial suitable for an autosampler. The cap with the rubber septum was then crimped onto the vial using a vial crimper supplied by Agilent. The method begins after all samples are loaded into the autosampler. The process was set to a THF flow rate of 1 ml/min through a mixed D column (2 in series) supplied by Phenomenex. The mixed D column was thermostatted at 40 ℃ to zero the refractive index detector baseline. With appropriate ventilation, the effluent is collected in a suitable vessel. The column was injected with the sample according to this method in a volume of 0.5 microliter per injection. The refractive index detector was thermostatted at 40 ℃ to prevent signal drift. The signal polarity is positive. The maximum pressure allowed on the column set was 600 bar. Analysis was performed using Agilent Chemstation software. A polystyrene reference sample from Agilent was run in a similar manner to establish a calibration curve. The molecular weight range of the standards is 500 to 30,000 daltons [ g/mol ]. The calibration curve may be a linear fit, or first or second order, depending on the column set used.