Cause Analysis and Solution of Epoxy AB Glue Yellowing of Epoxy Resin

2022-04-26T08:31:16+00:00April 26, 2022|

Epoxy resin is a kind of epoxy oligomer, which can form a three-dimensional network of thermosetting plastics when reacted with a hardener. Because of its strong adhesion, convenient curing, low shrinkage, good acid and alkali resistance, and excellent mechanical properties, it is widely used. However, epoxy products are prone to yellowing, poor weather resistance and toughness, which affect their own development. This article focuses on the problem of epoxy AB glue yellowing to discuss the causes and solutions. To solve the yellowing problem of epoxy AB glue, we first look at the composition of epoxy glue. Usually epoxy AB glue is composed of amine curing agent (polyetheramine, modified amine, aromatic amine, etc.), epoxy resin (mainly bisphenol A), accelerator, diluent, filler and other additives. The main factor of yellowing should be caused by amine curing agent, accelerator nonylphenol (NP) and bisphenol A resin. 1.Amine curing agent will not cause yellowing when [...]

Standard Fr4 Epoxy Glass Cloth Laminate Sheet Thickness

2022-04-25T08:57:55+00:00October 25, 2021|

FR4 is a code name of flame resistant materials with best performance in epoxy boards. Epoxy board made by glass fiber material and high heat resistance composite material. Main features: stable electrical insulation performance, good flatness, smooth surface,no pits, good for high performance electronic insulation requirement. Normally the manufacturing methods of FR4 fiberglass board are engraving, punching, milling, cutting. Size of FR4 is 10201220, larger size is 10301230, larger size need customized, Thickness are 0.3mm、0.4mm、0.5mm、0.6mm、0.8mm、1.0mm、1.2mm、1.5mm、1.6mm、1.8mm、2.0mm, etc, can be customized also 1-5mm. FR4 epoxy board made of glass fiber impregnated with epoxy resin with strong insulation and widely used in the electrical and electronic industry, especially in the charging cabinet circuit breaker as the partition on both sides, it acts as an insulating support. Jiujiang PTFE is an export manufacturer specializing in R & D, production and sales of epoxy board (Epoxy Glass Cloth Laminate Sheet). We use imported raw material [...]

Resistance of Copper Foil

2021-08-25T02:16:59+00:00August 24, 2021|

1 Scope This test method is used to determine the resistivity of copper foil. 2 Applicable Documents ASTM-B-193 Resistivity of Conductive Materials. 3 Test Specimen 3.1 Three samples should be selected at equal distances across the width of the material from each lot and the width and gauge length measured to the nearest 0.025 mm. 4 Equipment/Apparatus 4.1 Tester The resistance of the samples shall be measured with instruments of suitable sensitivity (see ASTM-B-193). 5 Procedure 5.1 Test 5.1.1 Resistance Determination Three samples shall be from each lot and the width and gauge length measured to the nearest 0.025 mm. The resistance of the samples shall be measured with instruments of suitable sensitivity, in accordance with ASTM-B-193. 5.1.2 For convenience, the distance between test points may be 15 cm, and the weight of the 2.5 cm wide sample being measured is determined by weighing a 2.5 cm x 15 cm [...]

Dielectric Withstanding Voltage (Hipot Method) – Thin Dielectric Layers for Printed Boards

2021-08-25T02:29:49+00:00August 24, 2021|

1 Scope The dielectric withstanding voltage test (Hipot test) consists of the application of a voltage higher than the operating voltage for a specific time across the thickness of the test specimen’s dielectric layer. This is used to prove that a printed board can operate safely at its rated voltage and withꢀstand momentary voltage spikes due to switching, surges, and other similar phenomena. Although this test is similar to a voltage breakdown test, it is not intended for this test to cause insulation breakdown. Rather, it serves to determine whether the test specimen’s layers have adequate withstanding voltage. This document is applicable to thin dielectric materials such as those defined by IPC-4821. The results can be indicative of a change or a deviation from the normal material characteristics resulting from manufacturing, processing or aging conditions. The test is useful for quality acceptance and in the determination of the suitability of [...]

Dielectric Breakdown Voltage and Dielectric Strength

2021-08-25T02:38:18+00:00August 24, 2021|

1 Scope These methods are designed for use in determining the dielectric strength of solid electrical insulating materials. 2 Applicable Documents None 3 Test Specimens 3.1 Dimensions The specimens shall be of such a diameter that flashover will not occur. This usually means that the diameter should be 76 mm or more. 3.2 Thick Solid Materials The breakdown voltage of thick solid materials may be so high that special test specimens cut or molded in reduced thickness may required. 3.3 At Various Thicknesses When it is desired to deterꢀmine the dielectric strength for different thicknesses of a material, it is necessary to test each different thickness, unless the variation due to thickness is already known. 3.4 Exceptional Conditions The special sizes of specimens required for determining dielectric strength under exceptional conditions shall be as specified in the material specification. 4 Equipment/Apparatus 4.1 Transformer The desired test voltage may be most [...]

Permittivity (Dielectric Constant) and Loss Tangent (Dissipation Factor) of Materials (Two Fluid Cell Method)

2021-08-25T03:00:27+00:00August 24, 2021|

1.0 Scope 1.1 Purpose This method is suitable for determining the volume permittivity, (dielectric constant) and loss tangent (dissipation factor) of insulating materials at 1 MHz. It is not dependent on either direct or indirect measurement of specimen thickness and therefore is very useful for thin films and laminates but may also be used on specimens up to approximately 6.35 mm [0.25 in] thick. It is useful for all ranges of permittivity and for loss tangent as low as 0.0005 providing the range and accuracy of the bridge used are adequate. 1.2 Description of Method The two fluid method utilizes air as one fluid and a suitable liquid, normally Dow 200 1.0CS silicone fluid, as the second. Using an established value for the permittivity of air, the values for the permittivity of the fluid and the sample may easily be calculated. The cell spacing is fixed during all readings but [...]

Dielectric Constant and Dissipation Factor of Printed Wiring Board Material—Clip Method

2021-08-25T03:15:04+00:00August 24, 2021|

1.0 Scope This test method is to determine the dielectric constant and dissipation factor of raw printed wiring board material at 1 MHz. 2.0 Applicable Documents None 3.0 Test Specimens Each specimen shall be 50.8 ± 0.076 mm [2.0 ± 0.003 in] in diameter by thickness of laminate or substrate material. Remove copper of metal-clad specimens by etching using standard commercial practices. At least three specimens are required. 4.0 Equipment/Apparatus 4.1 Meter A 1 MHz Digital LCR Meter, Hewlett Packard Mdl 4271A or equivalent. 4.2 Test Fixture Hewlett Packard Mdl 16022A test fixture or equivalent. 4.3 Specimen Holder A special specimen holder made as shown in Figure 1. This holder is designed to be compatible with the H/P test fixture, Mdl 16022A. 4.0 Procedure 5.1 Preparation 5.1.1 Prepare the specimens as specified in paragraph 3.0. 5.1.2 Calculate the effect thickness (inches) = Mass = Measured weight in grams Density = [...]

Conductor Temperature Rise Due to Current Changes in Conductors

2021-08-25T03:45:24+00:00August 24, 2021|

1.0 Scope This method is to comparatively determine the effects of printed conductor materials, conductor cross sectional measurements, substrate materials, and processes on the temperature D.C. current characteristics of printed wiring boards on a standard test sample. The temperature rise must be given for each conductor mateꢀ rials for a particular value of current, for a specified conductor cross sectional area, approximate geometry and substrate material. The results are reported as a plot of temperature rises versus current for each of the conductor materials, cross sectional areas, approximate geometry, and a substrate material. 2.0 Applicable Documents ASTM B 193 Conductor Materials, Electrical, Resistivity of QQ-S-571 Solder, Tin Alloy, Tin-lead Alloy, and Lead Alloy 3.0 Test Specimens Standard test specimen, see Figure 1 Test Pattern. Only one test pattern may be tested at one time, with current passing through only one conductor at one time. 4.0 Apparatus 4.1 Potentiometer (0.02% or [...]

Current Breakdown, Plated Through-Holes

2021-08-25T03:47:02+00:00August 24, 2021|

1.0 Scope To determine if the plated through-holes are sufficiently plated to withstand a relatively high current potential. 2.0 Applicable Documents None 3.0 Test Specimen Any plated through-holes on a test coupon or finished printed wiring boards. 4.0 Apparatus Power supply capable of generating 10 amps and having a suitable load resistor. 5.0 Procedure 5.1 Test Select a load resistor, such that when the resistor shunts the positive and ground terminals at a regulated amperes power supply, a current of 10 amps will flow through each plated through-hole in the circuit in series with the resistor, for 30 seconds. 5.2 Evaluation Examine for breakdown (opens) when the current is applied to each plated through-hole. 6.0 Notes The power supply unit should have a safety interlock mechanism because of the relatively high current required for this test.

Go to Top