Poly(esterimide) polymer, continuous process for producing the same, and process for applying the same on wire

Abstract

A continuous, solvent-free method for manufacturing poly(diacylimide) includes the following steps: a. feeding a polyester, a hydroxyl-functionalized compound, a diacylimide compound, and a catalyst into an extruder via one or more feed ports, wherein the polyester is selected from poly(ethylene terephthalate), poly(butylene terephthalate), poly(ethylene naphthalate), or poly(propylene furanoate); wherein the hydroxyl-functionalized compound is selected from monoethylene glycol, diethylene glycol, 1,4-butanediol, propylene glycol, dipropylene glycol, 1,4-cyclohexanemethanol, glycerol, trimethylolpropane, bisphenol A, or phenylene oxide. (2-Hydroxyethyl)isocyanurate; wherein the diimidin compound is at least a bifunctional compound with respect to a functional group capable of reacting in esterification and / or transesterification reactions; wherein the catalyst is present in an amount of 1 to 5 wt.% based on the total content of the composition provided in the extruder; b. mixing and melting the composition in the extruder at a temperature in the range of 80 to 120°C; c. reacting the composition in the extruder at a temperature in the range of 250 to 400°C; d. collecting the reaction mixture at the extruder outlet; and e. cooling the reaction mixture.

Description

Technical Field

[0001] The present invention relates to a continuous, solvent-free process for making poly(esterimide) polymers. Prior Art

[0002] Poly(esterimide) polymers (PEI) can be used for coating magnetic wire. Currently, these polymers are synthesized under batch conditions using stirred vessels equipped with overhead condenser systems to remove water. Typically, ethylene glycol or another glycol reacts with terephthalic acid and diimidyl diacid (DIDA) to form the hydroxyl-rich poly(esterimide). Batch synthesis requires between 10 and 30% solvent to facilitate reaction conditions in the stirred reactor. The most commonly used solvents for PEI are cresol or phenolic solvents, which are classified as toxic and environmentally harmful. Without solvent, the reactor tends to produce char on the heated walls, which is difficult to remove from the final product. Diimidyl diacids are also generally very insoluble and do not allow for effective stirring, resulting in slow reaction rates and agitator damage. Typically, a small amount of TNBT (0.1 to 0.3% of total resin solids) is added during synthesis.

[0003] US Pat. No. 4,605,710 discloses a powder composition suitable for providing a thermally stable electrically insulating coating on a wire when the composition is fused and cured thereon, the composition comprising a blend of a carboxyl-terminated polyester resin derived from at least one aromatic diacid and at least one aliphatic diol, at least about 5% by weight of at least one diamido diacid derived from the reaction product of at least one tricarboxylic anhydride and at least one diamine, and at least one triglycidyl isocyanurate, the isocyanurate being present in a molar ratio of epoxide functionality to total acid functionality of about 0.8 to about 1.5.

[0004] US 4,233,435 relates to a process for preparing a poly(esterimide) resin having increased anti-gel stability and wherein sublimation of a lower dialkyl ester of a phthalic acid component is substantially reduced during the process, the process comprising reacting a reaction mixture composition consisting essentially of: (I) an imide group-providing component selected from the group consisting of (A), (B), and (C), (A) being (1) a diamine component and (2) an anhydride component comprising at least one of (a) an aromatic carboxylic anhydride containing at least one esterified and substantially non-imidized other carboxyl group or (b) its corresponding acid containing two imide-forming ortho-carboxyl groups in place of an anhydride group, (B) being the carboxyl-functional polyimide reaction product of the diamine component and the anhydride component, and (C) being a mixture of (A) and (B); (II) providing The invention relates to a composition comprising an ester group, comprising (D) at least one diol containing two esterified hydroxyl groups, (E) at least one polyol containing at least three esterified hydroxyl groups, (F) at least one lower dialkyl ester of a phthalic acid component selected from the group consisting of terephthalic acid, isophthalic acid and mixtures thereof, and (G) a saturated aliphatic monohydric alcohol selected from the group consisting of n-hexanol, 2-ethylhexanol, n-nonanol, n-decanol, n-dodecanol, 2-butyloctanol, tetradecanol, 2,6,8-trimethylnonan-4-ol and mixtures thereof, wherein the reaction mixture comprises (a) about 0.035 to 0.25 mol of the diol, (b) about 0.025 to 0.15 mol of the polyol, (c) about 0.03 to 0.18 mol of the lower dialkyl ester, (d) about 0.1 to 0.2 mol of an aromatic carboxylic acid anhydride containing at least one other carboxyl group, and (e) 0.05 to 0.10 mol of a diamine component and about 1.0 to 20.0 parts of a monohydric alcohol, said equivalent amounts being based on 100 parts by weight of the total weight of the five components (a) to (e) recited therein.

[0005] US Pat. No. 4,795,790 discusses polyetherimide polymers comprising the reaction product of: (i) a diol component comprising at least one low molecular weight diol and at least one high molecular weight diol; (ii) at least one dicarboxylic acid or an ester thereof forming a reactive derivative thereof; and (iii) a reactant selected from (a) (1) at least one high molecular weight poly(oxyalkylene)diamine and (2) at least one tricarboxylic acid or a derivative thereof or (b) at least one high molecular weight polyoxyalkylene diimide diacid. The polymers of the present invention are reported to exhibit improved flexibility; and the diol component (i) contains at least an amount of the high molecular weight diol effective to improve the flexibility of the polymer.

[0006] CN 1252137 A relates to a method for preparing polyetherimide by continuously extruding reactants using a twin-screw reactor, and more particularly to a continuous extrusion twin-screw reactor based on bisphenol A diether anhydride and aromatic diamine.

[0007] CN 102471466 A provides a method for preparing polyimide molding powder via solid-phase polymerization. The method comprises the following steps: pulverizing and uniformly mixing an aromatic dibasic primary amine, an aromatic dibasic anhydride, and a toughening plasticizer, maleic anhydride ester, in a high-speed mixer; continuously feeding the mixed material into a continuously rotating screw-type conveying device to generate polyimide via reaction; rotating and extruding the generated polyimide, controlling the temperature of the device, forming polyimide particles, and pulverizing the polyimide molding powder. It is stated that the method avoids the use of organic solvents to achieve an environmentally friendly production process, and the prepared polyimide sheet has high strength and impact resistance, and the mechanical properties of the polyimide are superior to those of polyimide prepared via solvent methods.

[0008] US Pat. No. 4,073,773 discloses an extrusion melt polymerization process for the continuous production of polyetherimides. A mixture of an organic diamine and an aromatic bis(ether anhydride) is continuously fed through an inlet into a screw extruder having a second opening downstream of the inlet. The mixture is passed through a first extruder zone maintained at a low temperature to a zone where the mixture melts, and water of reaction is continuously removed through the second opening. A melt seal may be employed between the second and third openings, through which the water of reaction can be removed under vacuum.

[0009] PEI polymer is typically applied to conductors at a 30-50% solids content. Traditionally, the solvent is then burned as a source of high-cost fuel, adding to environmental emissions. Furthermore, the low solids content makes shipping hazardous materials around the world expensive, while 50-70% of the material does not add value to the final product. Coatings that can be applied solvent-free while replicating the performance of solvent-based coatings are desirable. This would eliminate hazardous solvent components and potentially reduce shipping volume by 50-70%. Summary of the Invention

[0010] The process of the present invention allows the production of PEI polymer without the use of any toxic or hazardous solvents and allows the direct application of freshly prepared PEI to a conductor.

[0011] Thus, the present invention relates to a continuous, solvent-free process for producing poly(esterimide) polymers, the process comprising the following steps: a. The polyester, hydroxyl-functional compound, diimide compound and catalyst are provided to the extruder through one or more feed ports.

[0012] Wherein the polyester is selected from poly (ethylene terephthalate), poly (butylene terephthalate), poly (ethylene naphthalate) or poly (propylene furanoate); Wherein the hydroxy-functional compound is selected from monoethylene glycol, diethylene glycol, 1,4-butanediol, propylene glycol, dipropylene glycol, 1,4-cyclohexanemethanol, glycerol, trimethylolpropane, bisphenol or ginseng - (2-hydroxyethyl) isocyanurate; Wherein the diimide compound is at least a bifunctional compound with respect to the functional group capable of reacting in the esterification and / or transesterification reaction; Wherein the catalyst is present in an amount of 1 to 5 wt.% based on the total content of the composition provided in the extruder; b mixing and melting the composition in an extruder at a temperature in the range of 80 to 120 ℃; c. allowing the composition to react in an extruder at a temperature in the range of 250 to 400 ℃; d. collecting the reaction mixture at the extruder outlet; and e. Cool the reaction mixture. Simple diagram description

[0013] 1 shows GPC curves of a poly(esterimide) prepared according to Example 1 ("extruded," dashed curve) and a typical poly(esterimide) prepared via a solvent-based process for benchmark purposes ("std," solid curve). Implementation Method

[0014] Preferably, no other materials are supplied to the extruder besides the polyester, the hydroxy-functional compound, the diimide compound, and the catalyst. Technically unavoidable impurities are not considered to violate this condition.

[0015] In the case of introducing other materials, preferably, the amount of polyester, hydroxyl-functional compound, diimide compound and catalyst provided in the extruder is 95 to <100 wt % of the total amount of materials provided in the extruder, more preferably 99 to <100 wt %.

[0016] Polyester materials are typically synthesized by reacting a diol or triol compound with a diacid or triacid compound. For example, polyesters can be formed by reacting ethylene glycol, glycerol, or other aliphatic triols (e.g., trimethylolpropane (TMP)) with aromatic diacids (e.g., phthalic acid, isophthalic acid, or terephthalic acid). This synthesis is well known in the art and is typically achieved by combining a polycondensation reaction with azeotropic distillation to remove the water formed by the reaction of the diol or triol compound with the acid compound. Suitable commercially available polyester compounds for the present invention include PET (poly(ethylene terephthalate)), PBT (poly(butylene terephthalate)), and PEN (poly(ethylene naphthalate)). Preferred molecular weight ranges for polyesters include 20 kDa to 40 kDa (corresponding to bottle-grade or textile-grade polyesters) and 60 kDa to 80 kDa (corresponding to film-grade polyesters).

[0017] Alternatively, bio-based polyester compounds such as poly(propylene furanoate) may be used. As understood herein, bio-based materials are materials that are intentionally made in whole or in part from substances derived from living (or once living) organisms, such as plants, animals, enzymes, and microorganisms (including bacteria, fungi, and yeasts).

[0018] The hydroxyl-functional compound used in the process of the present invention can be a diol compound or a triol compound. Examples of suitable diol compounds include monoethylene glycol, diethylene glycol, 1,4-butanediol, propylene glycol, dipropylene glycol, and 1,4-cyclohexanedimethanol. Examples of suitable triol compounds include glycerol, trimethylolpropane, bisphenol, or tris-(2-hydroxyethyl)isocyanurate. Triol compounds are preferred due to the thermal stability of the resulting poly(esterimide) polymer. Tris-(2-hydroxyethyl)isocyanurate is the most preferred compound for the process of the present invention due to the good electrical insulation properties of magnet wire coated with the resulting poly(esterimide) polymer.

[0019] The diimide compound used in the process of the present invention may be characterized by having the following general structure: (R1CO)2–N–R2–N–(R3CO)2, where R1, R2, and R3 can be the same or different and represent an aliphatic or aromatic organic moiety. Diimide-diesters of carboxylic anhydrides are disclosed in US Pat. No. 3,461,136. Various methods for producing these materials are mentioned in this reference. Diimide-diacid compounds can be formed by reacting a diamine with trimellitic anhydride.

[0020] Furthermore, diimide compounds are at least bifunctional with respect to functional groups capable of reacting in esterification and / or transesterification. These functional groups include carboxyl, hydroxyl, and carboxylate groups. This bifunctionality ensures that diimide compounds can act as chain extenders rather than chain terminators. For example, a compound having only one moiety, RC(=O)-O-CH2-CH2-OH, possesses two (trans)esterifiable functional groups, but is still considered monofunctional due to the lack of reactive sites elsewhere in the molecule.

[0021] Preferred diimide compounds are based on trimellitic anhydride as the carboxylic acid monomer. For the diamine component, any aromatic diphenylamine with an ether or single carbon linkage can be used, with methylenedianiline, oxydiphenylamine, and m- or p-phenylenediamine, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, or 1,3-bis(4-aminophenoxy)benzene being preferred. The resulting diimide from any of these combinations can then be reacted with any diol to produce a useful diimide. In this regard, 1,2-diols are preferred.

[0022] Particularly preferred is the diimide denoted "DIDE" used in the experimental part of the present invention.

[0023] The reaction can be catalyzed using various catalysts. Metal salts, such as acetates or octoates of metals (e.g., zinc, tin, or manganese), can be used. Alternatively, titanates (e.g., tetrabutyl titanate monomer, tetraisopropyl titanate, or tetrabutyl titanate polymer) can be used as catalysts. Typically, the catalyst is present in an amount of 1 to 5 wt.% based on the total composition.

[0024] The reaction mixture typically includes: 8 to 12 pbw (parts by weight) of polyester, 8 to 12 pbw of hydroxy-functional compounds 15 to 25 pbw of diimide compounds 1.4 to 1.9 pbw catalyst In this embodiment, the amount of polyester, hydroxyl-functional compound, diimide compound, and catalyst provided in the extruder is preferably 95 to 100 wt %, more preferably 99 to 100 wt %, of the total reaction mixture. It is particularly preferred that no other materials other than the polyester, hydroxyl-functional compound, diimide compound, and catalyst are present, excluding technically unavoidable impurities.

[0025] The molten material collected at the extruder outlet can be used in various ways. It can be solidified for later use or kept in a molten state and used directly, for example, to coat a wire via a wire coating technique, as disclosed in WO 2016 / 038335. However, it is also possible to dissolve the solidified material in a suitable solvent, such as a cresol or phenol solvent.

[0026] This solution can also be used to coat wire using more conventional processes using techniques known to those skilled in the art.

[0027] The extruder used in the process of the present invention can be any type of extruder. Good results have been obtained by using a twin-screw extruder or a planetary extruder.

[0028] [Example] [ , , ] All polymer synthesis experiments were conducted using a Brabender Co-Rotating Clamshell Twin-screw Extruder Model 20 / 40D. The extruder contained four heating zones, a die adapter heating zone, and a die heating zone. The screw design included forward and reverse conveying elements, forward and reverse kneading blocks, and tooth elements. Polyethylene terephthalate (PET) was fed via a single-helix screw metering feeder. Tris(2-hydroxyethyl)isocyanurate (THEIC) and diethylene glycol diimide (DIDE) were fed via either a twin concave screw metering feeder or a single-helix screw metering feeder. The catalyst was premixed with THEIC. All materials were fed via a 3L stainless steel hopper. No other equipment was used unless otherwise specified.

[0029] The structure of DIDE is given below:

[0030] Example 1 PEI was synthesized using 1 pbw (part by weight) of THEIC, 1 pbw of PET, and 1.8 pbw of DIDE. 4 wt.% (based on the wt.% of the total composition) of tetra-n-butyl titanate was used as a catalyst. Preparation: Break the DIDE solid into lumps and grind into a fine powder using a jaw crusher. Combine the DIDE powder with the THEIC powder and TNBT in a gallon jug (leaving ~1 / 3 of the jug free to allow for proper mixing) and shake on a paint shaker for 15 minutes. The TNBT will form small clumps / pellets with the powder. Break up any lumps and shake the mixture for an additional 10 minutes.

[0031] Extruder conditions: Screw Design – V3 (Multi-stage kneading block) Screw speed – 250 rpm Extruder temperature set points: 100, 300, 300, 300, 300, 300, 300°C PET feed rate – ~20 g / min DIDE / THEIC / TNBT blend feed rate – ~59 g / min Procedure: Heat the extruder to the appropriate temperature and turn on the drive. Feed the PET pellets using a single-screw feeder and the DIDE / THEIC / TNBT mixture using a twin-screw feeder. Allow the material to flow from the extruder for 2-3 minutes to allow equilibrium to be reached within the extruder. Collect the synthesized PEI into an unlined metal can and allow it to cool to room temperature before processing. Characterize the solid using a parallel plate rheometer and observe a composite viscosity of 550 Pa·s at 180°C. Record a melt flow index (MFI) of 14 g / 10 min at 160°C and a 3.8 kg weight.

[0032] The resulting polymer was dissolved in solvent and applied to a 1.0 mm copper wire. An oven temperature of 380 to 450° C. was used to achieve final wire curing. The properties were identical to those obtained from conventionally prepared PEI wire enamels. The intensity scale on the y-axis refers to the output signal of the refractive index sensor. The eluent was a 70 / 30 mixture of THF and DMF and calibration was performed using polystyrene standards. The molecular weights determined were: [PEI] [Extrusion] [PEI std] [Mn [Da]] 4393 2807 [Mw [Da]] 158086 6074 [Mz [Da]] 1.076 ∙ 10 7 30259 [Mp [Da]] 5029 1663 [Mw / Mn] 35.986 2.164

[0033] Example 2 (Comparison) PEI was synthesized using 1 pbw (part by weight) of THEIC, 1 pbw of PET, and 1.8 pbw of DIDE. 0.2 wt.% (based on the total wt.% of the composition) of tetra-n-butyl titanate was used as a catalyst.

[0034] Preparation: Break the DIDE solid into lumps and grind into a fine powder using a jaw crusher. Combine the DIDE powder with the THEIC powder and TNBT in a gallon jug (leaving ~1 / 3 of the jug free to allow for proper mixing) and shake on a paint shaker for 15 minutes. The TNBT will form small clumps / pellets with the powder. Break up any lumps and shake the mixture for an additional 10 minutes.

[0035] Extruder conditions: Screw Design – V3 (Multi-stage kneading block) Screw speed – 250 rpm Extruder temperature set points: 100, 250, 250, 250, 250, 250, 250°C PET feed rate – ~20 g / min DIDE / THEIC / TNBT blend feed rate – ~59 g / min Procedure: Heat the extruder to the appropriate temperature and turn on the drive. Use a single screw feeder to feed the PET pellets and a twin screw feeder to feed the DIDE / THEIC / TNBT mixture. Allow the material to flow from the extruder for 2 to 3 minutes to allow the extruder to reach equilibrium. The synthesized PEI is collected in an unlined metal can and allowed to cool to room temperature before processing. The collected solid has a broad molecular weight distribution and contains unreacted PET. This material is not completely soluble in THF, and the presence of a material mixture is confirmed.

[0036] Due to the poor physical properties of the mixture, the resulting polymer could not be applied to copper wire.

Claims

1. A continuous, solvent-free method for manufacturing poly(dimethimide) polymers, the method comprising the steps of: a. feeding a polyester, a hydroxyl-functionalized compound, a dimethimide compound, and a catalyst into an extruder, wherein the polyester is selected from poly(ethylene terephthalate), poly(butylene terephthalate), poly(ethylene naphthalate), or poly(propylene furanoate); wherein the hydroxyl-functionalized compound is selected from monoethylene glycol, diethylene glycol, 1,4-butanediol, propylene glycol, dipropylene glycol, 1,4-cyclohexaneethanol, glycerol, trimethylolpropane, bisphenol, or tris-(2-hydroxyethyl) a) Isocyanurate; wherein the diimidin compound is at least a bifunctional compound with respect to a functional group capable of reacting in esterification and / or transesterification reactions; wherein the catalyst is present in an amount of 1 to 5 wt.% based on the total content of the composition provided in the extruder; b) mixing and melting the composition in the extruder at a temperature in the range of 80 to 120°C; c) reacting the composition in the extruder at a temperature in the range of 250 to 400°C to obtain a reaction mixture; d) collecting the reaction mixture at the outlet of the extruder; and e) cooling the reaction mixture.

2. The method of claim 1, wherein no other materials are provided in the extruder except for polyester, hydroxyl functional compound, diamide compound and catalyst.

3. The method of claim 1, wherein in step a. the following are provided in the extruder: 8 to 12 pbw (parts by weight) of the polyester, 8 to 12 pbw of the hydroxyl functional compound, 15 to 25 pbw of the diimidimide compound, and 1.4 to 1.9 pbw of the catalyst.

4. The method of any one of claims 1 to 3, wherein the extruder is a twin-screw extruder.

5. The method of any one of claims 1 to 3, wherein the polyester is polyethylene terephthalate or polybutylene terephthalate.

6. The method of any one of claims 1 to 3, wherein the hydroxyl functional compound is tris-(2-hydroxyethyl)isocyanurate.

7. The method of any one of claims 1 to 3, wherein the diimidin compound has the following structure:

8. The method of claim 1, wherein the catalyst is a titanate compound.

9. A poly(esterimide) polymer that can be obtained by the method of claim 1.

10. A method for applying a poly(esterimide) polymer to a line, wherein the reaction mixture collected from the extruder according to the method of claim 1 is applied to the line.

11. The method of claim 10, wherein the poly(esterimide) polymer is dissolved in a solvent before being applied to the line.

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