IPC-TM-650 EN 2022 试验方法.pdf - 第331页

1 Scope This test method is designed to determine the glass transition temperature of dielectric materials used in printed boards by differential scanning calorimetry (DSC). It is suitable for prepreg, metallic clad or u…

5.3.3 Record the temperature, T

(2%), at which the mass

of the sample is 2.0% less than its mass measured at 50°C.

5.3.4 Record the temperature, T

(5%), at which the mass

of the sample is 5.0% less than its mass measured at 50°C.

6 Results Report the following information:

a) The initial mass of the sample.

b) The room temperature and relative humidity under which

testing was conducted.

c) The thermal decomposition temperature, T

(2%).

d) The thermal decomposition temperature, T

(5%).

7 References

IPC-TM-650

Method 2.3.40, Thermal Stability

ASTM D-3850 Standard Test Method for Rapid Thermal

Degradation of Solid Electrical Insulating Materials by Thermo-

gravimetric Analysis

IPC-TM-650

Number

2.4.24.6

Subject

Decomposition Temperature (T

) of Laminate Material Using TGA

Date

4/06

Revision

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1 Scope This test method is designed to determine the

glass transition temperature of dielectric materials used in

printed boards by differential scanning calorimetry (DSC). It is

suitable for prepreg, metallic clad or unclad laminate, and

printed boards. It also provides a determination of relative

degree of cure, or Cure Factor, for some types of materials.

2 Applicable Documents None

3 Test Specimens

3.1 Size and Configuration

The specimen shall be a

solid piece weighing between 10 to 40 mg. For very thin

materials, multiple pieces may be used to achieve the speci-

fied weight. The specimen shall be of a size and configuration

that fits within the sample pan of the DSC equipment. See 6.1

regarding use of a powdered specimen.

3.2 Quantity and Sampling The sampling shall be ran-

domly taken from the material in question, and, unless other-

wise specified, one specimen shall be tested, to be taken

from the material in question.

4 Equipment/Apparatus

4.1

Differential scanning calorimeter capable of measuring

and recording heat capacity of the applicable material.

4.2 Nitrogen gas supplied at a constant rate, suitable for

purging and calibrating the DSC cell.

4.3 Equipment suitable for specimen preparation in accor-

dance with 3.1, such as a punch press.

4.4 Standard aluminum sample pans and lids and crimping

press.

4.5 Air circulating oven capable of maintaining 105±2°C

[221 ± 3.6 °F].

4.6 Desiccator or drying cabinet capable of maintaining an

atmosphere less than 30% RH at 23 ° C [73.4 °F].

5 Procedure

5.1 Specimen Preparation

5.1.1

Metallic clad laminates and printed boards shall be

tested with metallic cladding left in place whenever possible.

5.1.2 For all laminates and printed boards, the sample shall

be preconditioned by baking for 2 ± 0.25 hours at 105 ± 2 °C

[221 ± 3.6 °F], then cooled to room temperature in a desicca-

tor or drying cabinet for at least 1/2 hour prior to testing.

5.1.3 The specimen shall be prepared from the baked

sample in accordance with 3.1. Edges shall be smoothed

and burrs removed by light sanding, or equivalent, to achieve

proper thermal conduction. Use care to minimize stress or

heating of the specimen.

5.1.4 Place the specimen in a standard aluminum sample

pan with an aluminum lid. Use of a lid and crimping is optional.

For referee purposes, a cover lid crimped onto the sample

pan shall be used. If the specimen is a powder, the pan shall

be covered with a lid and crimped shut.

5.1.5 For referee purposes, a suitable reference shall be

prepared by adding an equivalent weight of aluminum lids to

the reference pan to match the weight of the sample. For

example, if the sample weight is 8 mg, enough lids should be

added to the reference pan to weigh 8 mg.

5.2 Test

5.2.1

Follow start up and operating procedures in accor-

dance with instructions supplied by the test equipment

manufacturer.

5.2.2 Conditioning Pre-Scan:

5.2.2.1 The point of the pre-scan is to erase previous ther-

mal history and the effects on morphology of the sample.

3000 Lakeside Drive, Suite 105N

Bannockburn, IL 60015-1249

IPC-TM-650

TEST METHODS MANUAL

Number

2.4.25

Subject

Glass Transition Temperature and Cure Factor by

DSC

Date

11/17

Revision

Originating Task Group

Laminate/Prepreg Materials Subcommittee (3-11)

Material in this Test Methods Manual was voluntarily established by Technical Committees of IPC. This material is advisory only

and its use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of this

material. Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.

Equipment referenced is for the convenience of the user and does not imply endorsement by IPC.

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5.2.2.2 Perform the pre-scan from at least 30 °C [54 °F]

below the transition region to a temperature 10 °C [18 °F]

above the transition region at a rate of 20 °C/min [36 °F/min].

Then quench-cool to at least 30 °C [54 °F] below the transi-

tion region, as rapidly as possible.

5.2.3 Analysis Scan.

5.2.3.1 Start the scan at a temperature that is at least 30 °C

[54 °F] lower than the anticipated transition region. The heat

rate shall be stabilized before the transition region is reached.

5.2.3.2 Unless otherwise specified, scan at a rate of 20 °C/

min [36 °F/min].

5.2.3.3 When the transition has been observed, scan at

least 30 °C [54 °F] beyond the transition region.

5.2.3.4 Record the results as T

5.2.4 Determination of Cure Factor.

5.2.4.1 The following steps shall be performed only if the

Cure Factor is applicable and required by the governing speci-

fication (see Table 1). It does not apply to prepreg.

5.2.4.2 Continue the scan at a rate of 20 °C/min [36 °F/min]

to a temperature per Table 1. The specimen is then held at

the isothermal temperature for a time per Table 1.

5.2.4.3 The specimen is immediately cooled to initial condi-

tions and a second glass transition scan carried out in accor-

dance with 5.3.3. Record as T

5.3 Calculation

5.3.1 Determination of T

The midpoint temperature T

(°C) as described in Figure 1 reported as the T

is the point

on the thermal curve corresponding to 1/2 the heat flow dif-

ference between the extrapolated onset and extrapolated

end. If suitable computer software is available, the automatic

calculation of the glass transition temperature is allowable pro-

vided the value calculation is either the midpoint or the steep-

est deflection and not the onset temperature. See Figure 1.

Table 1 Resin Type Temperature Requirements

Resin Type Isothermal

Temperature Hold Time at Temperature

Difunctional and Tetrafunctional Epoxies 175 °C±2°C 15±0.5minutes

Multifunctional and High Temperature Epoxies 190 °C±5°C 15±0.5minutes

BT- Epoxies

N/A N/A

Polyimides

N/A N/A

Cyanate Esters

N/A N/A

1) Or in accordance with manufacturer’s recommendations.

2) Certain materials are not compatible with the Cure Factor determination, as they will exhibit an increasing transition temperature

with each exposure to a temperature above the cure level.

IPC-TM-650

Number

2.4.25

Subject

Glass Transition Temperature and Cure Factor by DSC

Date

11/17

Revision

Page2of4