Stock material or miscellaneous articles – Composite – Of epoxy ether
Reexamination Certificate
2001-01-20
2002-04-30
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Composite
Of epoxy ether
C428S311110, C428S297400, C525S134000, C525S135000, C525S154000, C525S155000, C528S129000, C528S245000, C528S501000, C528S50200C, C528S503000
Reexamination Certificate
active
06379800
ABSTRACT:
BACKGROUND AND PRIOR ART
This application relates to subject matter which is similar to that of applicant's U.S. Pat. Nos. 6,001,950 of Dec. 14, 1999 and 6,140,420 of Oct. 31, 2000 but the polyphenolics (condensates) and epoxy derivatives of this invention show an unexpected higher increase in fluorescence as compared to that of the prior patents while, at the same time, showing a high ultraviolet (UV) absorbance.
Polyphenolics, such as those prepared from the condensation of glyoxal and a molar excess of a phenolic monomer such as phenol itself in the presence of an acid catalyst, find utility in the same manner as other polyphenolics and particularly for preparing epoxidized polyphenolics which can be used for coatings and electronic applications as well as adhesives and laminates in the production of printed circuit boards.
Glyoxal-phenolic condensates contain a variety of compounds, including polyphenolics such as di-, tri-, tetraphenolics and higher polyphenolics. When the reactants are phenol itself and glyoxal, the polyphenol is a mixture wherein the predominant tetraphenolic compound is tetrakis(4-hydroxyphenyl)ethane (TPE) which is also referred to as 1, 1, 2, 2-tetrakis(4-hydroxyphenyl)ethane. Glycidylation of the tetrakis(4-hydroxyphenyl)ethane gives the tetraglycidyl ether of tetrakis(4-hydroxyphenyl)ethane. The polyphenolics of this invention will typically contain less than about 6%, preferably less than 4% and particularly less than about 2% or 3% such as less than 1% of TPE.
The condensates and epoxy derivatives of this invention are particularly useful for measurement of fluorescence and/or UV absorbance when automatic optical inspection (AOI) is used for quality control such as in the manufacture of laminates. They can be used alone, after epoxidation, as adducts with epoxy resins, adducts of epoxidized condensates with phenolic novolacs, or in blends with conventional phenolic novolacs and/or prior art glyoxal phenolic condensates such as those of U.S. Pat. No. 6,001,950 which do not have the high fluorescence of this invention. High UV absorbance is desirable for the manufacture of laminates used in electronic applications such as high density multilayer printed circuit boards.
Applicant has found process conditions and the use of oxalic acid as catalyst for obtaining polyphenolics, epoxy derivatives, and compositions containing the foregoing which have unexpectedly high fluorescence with a relatively high UV absorbance. The fluorescence is substantially higher than glyoxal-phenolic condensates prepared by other methods and catalysts within the wavelengths generally used for AOI quality control. Photoimageable materials can be used in conjunction with these condensates.
In this invention, polyphenolics can be obtained with the desirable optical properties, and depending on the method used in making the polyphenolic, one or more additional desirable properties such as: (a) preparation of an essentially metal ion-free polyphenolic without recourse to catalyst filtration or neutralization and water washing steps wherein recovery of phenolic monomer is simplified and the reactor yield is increased in those cases where the catalyst is not neutralized with a metal ion; (b) preparation of polyphenolics with increased solubility in organic solvents; (c) performance of the condensation with a single addition of glyoxal and a single vacuum distillation whereas some other methods use multiple glyoxal additions and vacuum distillations; or the level of tetra(4-hydroxyphenyl)ethane can be unexpectedly low.
The phrase “aldehyde equivalents” as used in this application refers to aldehyde in the glyoxal charged or remaining in the reaction mixture or product when measured by the below described method. Such measurements are reported in aldehyde equivalents reacted in comparison with the aldehyde equivalents charged to the reaction mixture. Thus, if measurements of aldehyde equivalents of the glyoxal charged to the reactor show a total of X aldehyde equivalents and measurements after reaction in the reaction mixture later show aldehyde equivalents of ½ of X, then the aldehyde equivalents reacted are 50% of that charged. Certain ketone groups, referred to as “reactive ketones” are also measured by the below test method. The ketone groups may be formed during the condensation reaction and these are included in measuring of the aldehyde equivalents and are considered as part of the aldehyde equivalents herein. The term “reactive ketone” is used to describe those ketones which affect the per cent of aldehyde equivalents.
The method for determining aldehyde equivalents is by taking 1.0 gram of reaction mixture and diluting it with 50 ml of methanol. The pH is then adjusted to 3.5 with dilute sodium hydroxide. There is then added, to the pH adjusted sample, 25 ml of 10% aqueous hydroxylamine hydrochloride with stirring. The sample is stirred for 10 minutes and then the sample is back titrated with 0.25 Normal (N) sodium hydroxide to pH of 3.5. The number of milliliters (mis) (the titre) of the sodium hydroxide solution used to back titrate the sample to a pH of 3.5 is used to calculate the aldehyde equivalents.
The aldehyde equivalents for the sample are then calculated by the following formula: (2.9 times 0.25 times (mis sodium hydroxide titre).The value obtained by this formula is then compared to the aldehyde equivalents obtained by the above method and formula based on one gram of an unheated mixture of phenolic monomer and glyoxal in the weight ratio of glyoxal to phenolic monomer used until that time or the time in question, after correcting for water which may have been added or remove, e.g., by distillation, in order to determine the percent aldehyde equivalents reacted.
Apart from the above method for determining aldehyde equivalents, the aldehyde groups of the starting glyoxal can simply be compared with the aldehyde groups and reactive ketone groups in the reaction mixture or product to determine the amount of aldehyde and reactive ketone groups reacted. In making the percentage calculations, adjustments again need to be made for the addition or removal of water and the weight ratio of phenolic monomer to gyloxal used at the time in question as compared to that of the initial mixture containing the unreacted glyoxal, keeping in mind that each molecule of glyoxal has two aldehyde groups.
Unless otherwise indicated, the fluorescence measurements herein are based on the maximum counts for a 0.05% solution of the polyphenolic or derivative thereof, dissolved in tetrahydrofuran (THF) at an excitation wave length of 442 nm (nanometers) when measured within the range of about 450 to 650 nm. Although the range of 450 to 650 was measured, the maximum counts for the products of this invention occurs at the 525-535 nm range. It is the maximum counts that are compared in the measurements given in this application. The time for measurement of the maximum counts and the time during which the excitation is measured, such excitation time also referred to as “acquisition time”, are the same and in the measurements in this application such time was either one-half second or one second.
When the polyphenolic or derivative thereof is compared with Acridine Orange Base which was purchased from the Aldrich Chemical Company, all experimental conditions are the same except that the Acridine Orange Base is diluted and measured at a concentration of 0.31 mg/liter (milligrams per liter) dissolved in methanol. This concentration of Acridine Orange Base gives about the same amount of fluorescence as that of a 0.05% by weight solution in THF for the resin of Example 7 in applicant's U.S. Pat. No. 6,001,950.
The Acridine Orange Base itself is a solution containing about 75% of the dye when sold by the Aldrich Chemical Co. of Milwaukee, Wis. The Acridine Orange base of Aldrich Chemical Company is described on page 33 of the Aldrich Chemical Company catalogue which is dated 2000-2001. The instrument used to make the measurements is a CM 1000 instrument. CM 1000 refers to Cure Monitor
Borden Chemical, Inc.
Dawson Robert
Feely Michael J.
Maskas George P.
Van Wyck Kenneth P.
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