KR20120112380A - Methods of making solid epoxy resin - Google Patents

Abstract

The present invention relates to a composition containing a solid epoxy resin in discrete particulate form and a process for the preparation thereof. The method comprises one or more polyphenol compounds, epichlorohydrin, 1,3-dichloro-2-propanol, 2,3 in a single phase homogeneous reaction mixture comprising a water miscible organic solvent, water, a catalyst and a dispersant. Condensing one or more condensation compounds selected from dichloro-2-propanol, epoxy novolacs and analogs thereof.

Description

Manufacturing method of solid epoxy resin {METHODS OF MAKING SOLID EPOXY RESIN}

The present invention relates to a composition containing a solid epoxy resin (SER) and a process for its preparation, and in particular to a composition of the SER in discrete particulate form by a condensation reaction and a process for its preparation.

Epoxy is a thermosetting polymer formed from the reaction of an epoxy "resin" with a polyamine "curing agent". Epoxy has a wide range of applications, including coatings, adhesives, fiber-reinforced plastic materials, composite materials, and electrical laminates. In general, epoxies are known for their adhesion, chemical and heat resistance, mechanical properties and electrical insulation properties.

Commercially produced SERs have been prepared in a variety of ways, including the condensation of bisphenol and epichlorohydrin in water. Some approaches use cellulosic additives such as carboxymethylcellulose sodium salts to help form epoxy suspensions. However, this can lead to the formation of an undesirable gel content due to the reaction between the epoxide and the multiple primary hydroxyl groups on the cellulose molecule. A further disadvantage of the above described approach may include the retention of unwanted impurities such as chloride ions (Cl ⁻ ) in the SER. Thus, after the SER is formed, the SER may need to perform additional steps to reduce impurities into commercial standards. This additional step requires more time, material and energy, increasing production costs.

"Solid epoxy resin (SER)" refers to an epoxy resin in its physical form that is in the solid state at ambient temperature within the range of 23 degrees Celsius (° C.) to 25 ° C.

"Dispersed particulate form" refers to an SER composed of distinct epoxy resin particles, such as powders.

"As-made SER" refers to a precipitated SER in discrete particulate form prior to performing further steps for the reduction of impurities.

"Solution" refers to polyphenol compounds dissolved in water miscible organic solvents, water and catalyst.

"Single phase homogeneous reaction mixture" refers to solutions, dispersants and condensation compounds in the liquid phase.

"Biphase mixture" refers to a single phase homogeneous reaction mixture in the liquid phase and precipitated SER in the solid phase.

"Dispersant" refers to a substance that provides a stable suspension of condensation compounds in a single phase homogeneous reaction mixture.

"Secondary alcohol" refers to an alcohol in which the carbon atom to which the hydroxyl group is bonded is bonded to two carbon atoms.

"Tertiary alcohol" refers to an alcohol in which the carbon atom to which the hydroxyl group is bonded is bonded to three carbon atoms.

"Molecular" refers to the smallest particle of a substance that retains the chemical and physical properties of the substance and consists of two or more atoms.

"Gel" refers to THF insoluble content and is formed by side reactions between the condensation compound and the hydroxyl groups on the cellulosic additive.

The present invention relates to one or more polyphenol compounds, epichlorohydrin, 1,3-dichloro-2-propanol, 2,3-dichloro-2-propanol, epoxy novolacs and analogs thereof in a single phase homogeneous reaction mixture. Provided is a method of condensing at least one condensation compound selected from to produce SER in discrete particle form. The process is in the form of discrete particulates having a Cl ⁻ concentration in commercial standards, for example up to 100 parts per million (ppm) per million (≦) and without a detectable gel, for example with a gel of less than 0.01 wt% (<). SER is produced at the time of manufacture.

The method includes forming a solution. The amount of water miscible organic solvent used in the solution is in the range of 5% by weight (wt%) to 20% by weight, and preferably 10% to 15% by weight, based on the total weight of the single phase homogeneous reaction mixture. The water miscible organic solvent is selected from secondary or tertiary alcohols. Examples of alcohols include 2-propanol, 2-butanol, t-butanol, 2-methyl-2-butanol, 2-pentanol, 3-pentanol, 2-methyl-2-pentanol, 4-methyl-2-pentane Ol and combinations thereof. In addition, the water miscible organic solvent can be selected from ethers. Examples of ethers include 1-methoxy-2-ethanol, 1-ethoxy-2-ethanol, 1-butoxy-2-ethanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1 Isobutoxy-2-propanol, 1-phenoxy-2-propanol, 1-methoxy-2-butanol, 3-methoxy-1-butanol, 2-methoxy-2-methylbutanol, ethylene glycol monoisopropyl Ethers, ethylene glycol monoisobutyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-tert-butyl ether and combinations thereof. Primary alcohols, or alcohols with more than one primary hydroxyl group per molecule, are not suitable for use as water miscible solvents, since their reaction with epoxides is unintentional and diol, triol or polyol This will result in unwanted gel content.

The catalyst includes a material capable of catalyzing the condensation of a polyphenol compound with a condensation compound. The catalyst includes an inorganic compound. The inorganic compound is dissolved in water to form an alkaline solution. Examples of inorganic compounds are oxides and hydroxides of metals such as lithium (Li), sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), zinc (Zn) and aluminum (Al). The catalyst is present in an amount that provides a molar ratio of catalyst to condensation compound in the range from 0.5: 1 to 10: 1, and more preferably in the range from 1: 1 to 1.5: 1.

The polyphenolic compound may be selected from diphenols, for example bisphenols. Examples of bisphenols include bisphenol A, brominated bisphenol A, bisphenol F, bisphenol K, bisphenol S, hydroquinone, resorcinol and 1,1-cyclohexane bisphenol. Novolak resins may also be used alone or in combination with one or more bisphenols. Non-phenolic polyhydroxy compounds such as 1,4-bis (hydroxymethyl) benzene, 1,3-bis (hydroxymethyl) benzene, 1,4-bis (hydroxymethyl) -cyclohexane, 1,3-bis (hydroxymethyl) cyclohexane hexanediol and cyclohexanediol may also be present in the solution. The amount of polyphenol compound used is expressed on a molar ratio of polyphenol compound to condensation compound. The molar ratio is in the range of 1: 1 to 1:10, more preferably 1: 1 to 1: 2, even more preferably 1: 1 to 1: 1.5.

The method includes adding a dispersant to the solution. The dispersant preferably contains 1 or less hydroxyl groups (or equivalent groups) per molecule. The use of dispersants having 1 or less hydroxyl groups per molecule minimizes side reactions between the condensation compound and the hydroxyl groups of the dispersant, and is at most 0.18% by weight, more preferably at most 0.12% by weight, even more preferably at 0.01% by weight. SER is formed in the production of discrete particulate forms having gels in the range of less than%. Dispersants can be selected from methoxypolyethylene glycol (MPEG). For example, CARBOWAX ™ can be used as a dispersant. MPEG may have a molecular weight in the range of 1000 to about 20000, preferably 2000 to 10000, even more preferably 2000 to 4000. In addition, the dispersant may be selected from ethylene oxide / propylene oxide di-block copolymers and ethylene oxide / propylene oxide tri-block copolymers. In addition, mixtures of various dispersants may be used. The amount of dispersant is from 0.005% to 2% by weight, more preferably from 0.01% to 1% by weight, even more preferably from 0.02% to 0.5% by weight, based on the total weight of the dispersant, the polyphenol compound and the condensation compound. It is in range.

The method includes adding one or more condensation compounds and a dispersant to a solution to form a single phase homogeneous reaction mixture. The condensation compound is suspended in the single phase homogeneous reaction mixture using a dispersant. The condensation compound may be selected from at least one of epichlorohydrin, 1,3-dichloro-2-propanol, 2,3-dichloro-2-propanol, epihalohydrin and analogs of these compounds. Other condensation compounds such as diepoxy compounds such as cyclooctene diepoxide, divinylbenzene diepoxide, 1,7-octadiene diepoxide, 1,3-butadiene diepoxide, 1,5- Diepoxides of hexadiene diepoxide and 4-cyclohexenecarboxylate 4-cyclohexenylmethyl ester can be used. In addition, there may be glycidyl ether derivatives of novolacs such as phenol novolac and cresol novolac. In addition, mixtures of various condensation compounds can be used. The total amount of the condensation compound and the polyphenol compound used in the single phase homogeneous reaction mixture is from 10% to 90% by weight, preferably from 30% to about 70% by weight, even more preferably from 30% to 40% by weight. It is in range.

The single phase homogeneous reaction mixture may contain one or more additional substances. Examples of such materials include co-dispersants and emulsifiers, for example quaternized or hydrophobically modified cellulose ethers. Examples include water soluble polyethylene glycol copolymers, water soluble polyethylene glycols having functional end groups, and water soluble polyethylene oxide copolymers. Further examples are water insoluble inorganic salts, for example carbonates, phosphates and sulfates of alkaline earth metals, for example calcium phosphate (Ca ₃ PO ₄ ), magnesium carbonate (MgCO ₃ ), calcium carbonate (CaCO ₃ ), barium carbonate (BaCO ₃ ) and calcium sulfate (CaSO ₄ ). In addition, various phase transfer agents may be added, for example benzyl trimethyl ammonium chloride. Such materials may range from 0.02% to 2% by weight, preferably from 0.02% to 1% by weight, more preferably from 0.02% to about 0.05% by weight, based on the total weight of the additional material, polyphenol compound, dispersant and condensation compound. It can be used in the range of%.

In the case of the process described above, the reaction temperature is in the range of 30 ° C to 150 ° C, more preferably 40 ° C to 150 ° C, even more preferably 70 ° C to 150 ° C. The process of the invention is carried out at 1 standard atmospheric pressure (atm) (101.3 kilopascals), although other pressures, for example 5 atm or less, or vacuum may be used.

In preparation, the SER precipitates from the single phase homogeneous reaction mixture and the single phase homogeneous reaction mixture becomes a two phase mixture. In the production of discrete particulate forms, the SER can be separated from the biphasic reaction mixture by standard techniques such as filtration, washing, neutralization and drying. An example of a neutralizing agent for neutralizing excess catalyst is a 25 wt% sodium hypophosphate (NaH ₂ PO ₄ ) solution.

In preparation, the SER is free of detectable gels and has a Cl ⁻ concentration of 150 ppm or less, more preferably 100 ppm or less. At least 98% (≧) of the particles of the SER in the production of discrete particulate forms have a particle diameter size in the range of 10 micrometers (μm) to 1000 μm. Advantageously, some particles are in the range of 20 μm to 900 μm and the preferred size is 800 μm or less. The average particle size is in the range of 10 μm to 500 μm. Advantageously the average particle size is in the range from 50 μm to 300 μm, even more preferably up to 200 μm can also be achieved.

The number average molecular weight (Mn) of the SER in the production of discrete particulate forms is in the range from 1000 to 5000, preferably from 1800 to 4000, even more preferably from 2000 to 3000. The weight average molecular weight (Mw) of the SER in the production of discrete particulate forms is in the range from 2000 to 9000, more preferably from 3500 to 7000, even more preferably from 4500 to 6400. Molecular weights are sometimes expressed in daltons or grams per mole, but are dimensionless.

Example  One ( Comparative example )

310 grams (g) of deionized water, 40 g of 2-propanol (CAS # 67-63-0) in a 1 liter (L) round bottom flask equipped with an overhead stirring device, cooling condenser and heating mantle 30.8 g and 64.1 g of bisphenol A (CAS # 80-05-7) were added to form a solution. The solution was heated to 40 ° C. with stirring at 570 revolutions per minute (rpm) under continuous nitrogen purge. After bisphenol A was completely dissolved, 0.24 g of MPEG 2000 (Carbowax ™, available from The Dow Chemical Company) was added to the solution. After stirring the flask contents for 5 minutes, 32.5 g of epichlorohydrin was added to the solution to form a single phase homogeneous reaction mixture. The single phase homogeneous reaction mixture was heated to 50 ° C. with stirring, and when the flask contents became cloudy, 0.09 g of cationic hydroxylethyl cellulose (CAS # 9004-65-3) and 10 g of deionized water were added. The biphasic reaction mixture was heated to 88 ° C. and maintained at 120 minutes.

For 120 minutes, samples were taken and tested for the phenolic OH concentration of the biphasic reaction mixture. If the phenolic OH concentration was less than 500 ppm, the biphasic reaction mixture was cooled to 40 ° C., then the contents were drained from the flask, the flask was washed three times with 800 g of deionized water and the washings were added to the flask contents. Excessive NaOH in the SER was neutralized with 25 wt.% NaH ₂ PO ₄ aqueous solution in preparation of the discrete particulate form. SER was isolated during preparation by filtration and vacuum drying at 20 ° C. for 10 hours. The resulting SER was a fine white powder, an average phenolic OH was 630 ppm, an average particle size was 71 μm and a molecular weight of Mn = 1710 and Mw = 3130. The Cl ⁻ concentration in the SER at the time of manufacture was 540 ppm. There was no detectable gel content.

Example  2 ( Comparative example )

Example 1 was repeated except that the following was changed. For the solution, the amount of 50% NaOH aqueous solution was changed to 27.4 g. MPEG 2000 was replaced by the same amount of MPEG 4000. For a single phase homogeneous reaction mixture, the amount of epichlorohydrin was changed to 29.1 g and the amount of 1 wt% cationic hydroxylethyl cellulose aqueous solution was changed to 3 g. The biphasic reaction mixture was heated to 88 ° C. for 180 minutes. The resulting SER had a phenolic OH concentration of 1190 ppm, an average particle size of 255 μm and a molecular weight of Mn = 3010 and Mw = 6070. The Cl ⁻ concentration in the SER at the time of manufacture was 2880 ppm. Gel content was 0.12% by weight.

Example  3

Example 1 was repeated except that the following was changed. For the solution, the amount of the 50 wt% NaOH aqueous solution was changed to 37.0 g. MPEG 2000 was replaced by the same amount of MPEG 4000. For a single phase homogeneous reaction mixture, the amount of epichlorohydrin was changed to 39.0 g and the amount of 1 wt% cationic hydroxylethyl cellulose aqueous solution was changed to 3 g. The biphasic reaction mixture was heated to 70 ° C. for 135 minutes. The resulting SER had a phenolic OH concentration of 370 ppm, an average particle size of 255 μm and a molecular weight of Mn = 940 and Mw = 1650. The Cl ⁻ concentration in the SER at the time of manufacture was 55 ppm. There was no detectable gel content.

Example  4

Example 2 was repeated except that the following was changed. For the solution, the amount of 2-propanol was changed to 60.0 g. In the case of a single phase homogeneous reaction mixture, the amount of aqueous 1% by weight cationic hydroxylethyl cellulose solution was changed to 1.5 g. The biphasic reaction mixture was heated to 88 ° C. for 180 minutes. In the production of the resulting discrete particulate form, the SER had a phenolic OH concentration of 1190 ppm, an average particle size of 227 μm and a molecular weight of Mn = 2900 and Mw = 6240. The Cl ⁻ concentration in the SER was 74 ppm when prepared in discrete particulate form.

Example  5

Example 1 was repeated except that the following was changed. For the solution, the amount of 2-propanol was changed to 50 g. MPEG 2000 was replaced by MPEG 4000. In the case of a single phase homogeneous reaction mixture, the amount of aqueous 1% by weight cationic hydroxylethyl cellulose solution was changed to 1.5 g. The reaction mixture was heated to 88 ° C. for 180 minutes. The resulting SER had a phenolic OH concentration of 610 ppm, an average particle size of 220 μm and a molecular weight of Mn = 1800 and Mw = 3340. The Cl ⁻ concentration in the SER was 120 ppm when prepared in discrete particulate form.

Example  6 ( Comparative example )

Example 1 was repeated except that the following was changed. 250.0 g of deionized water, 30.8 g of 50% by weight aqueous NaOH solution and 64.1 g of bisphenol A were combined. 2-propanol was not used in this example. The flask contents were heated to 50 ° C. After bisphenol A was completely dissolved, the flask contents were cooled to 40 ° C. and 75.0 g of 0.33% by weight aqueous solution of hydroxypropylmethylcellulose (Methocel® F75M, The Dow Chemical Company) was added to the flask contents. 32.5 g of epichlorohydrin was added to the flask contents. The flask contents were heated to 95 ° C. with stirring and stirred at this temperature for 65 minutes. After the flask contents were cooled to 70 ° C., the contents were drained from the flask and the flask was washed three times with 350 g of deionized water. The resulting SER in the form of discrete particulates had a phenolic OH concentration of 1860 ppm, an average particle size of 254 μm, and a molecular weight of Mn = 1670 and Mw = 3120. The Cl ⁻ concentration in the SER was 5750 ppm when prepared in discrete particulate form. Gel content was 5.3% by weight.

Test Methods

Phenolic OH concentrations were tracked using a Shimadzu UV1201 UV-Vis spectrophotometer. According to ASTM D512-04, SER was dissolved in preparation of the particulate form dispersed in acetone and nitric acid using methanol was titrated to determine Cl ⁻ concentration. The gel residue was dried and weighed and the gel content was determined by taking the ratio of the weight of the gel to the weight of the initial sample. Particle size was measured using a Beckman Coulter dynamic image analyzer equipped with RapidVue 2.006 software.

Claims (9)

In a single phase homogeneous reaction mixture comprising a water miscible organic solvent, water, a catalyst and a dispersant, at least one polyphenol compound, and epichlorohydrin, 1,3-dichloro-2-propanol, 2,3-dichloro- A process for preparing a solid epoxy resin in discrete particulate form comprising condensing at least one condensation compound selected from 1-propanol, epoxy novolacs and analogs thereof. The process of claim 1 wherein the single phase homogeneous reaction mixture is a two phase mixture when the solid epoxy resin precipitates from the single phase homogeneous reaction mixture. The method of claim 1 comprising selecting a water miscible organic solvent from the group consisting of secondary alcohols, tertiary alcohols, ethers, and combinations thereof. The process of claim 1, wherein the water miscible organic solvent is 2-propanol. The process of claim 1, wherein the dispersant is methoxypolyethylene glycol. The method of claim 1 further comprising performing condensation in the presence of a co-dispersant comprising a modified cellulose ether. The process according to claim 1, wherein the solution comprises up to 20% by weight water miscible organic solvent, based on the total weight of the single phase homogeneous reaction mixture. 8. The method of any one of claims 1 to 7, wherein the dispersant contains one or less than one hydroxyl group per molecule. A solid epoxy resin in discrete particulate form prepared by the method of claim 1, wherein the concentration of chloride ions in the solid epoxy resin in discrete particulate form is 150 ppm or less and contains less than 0.01 wt% gel.