Method for detecting glass yarn closed channel in glass fabric

Abstract

The invention provides a method for detecting a glass yarn closed channel in glass fabric, which comprises the following steps of: (1) stretching the glass fabric to be detected along the warp direction to obtain a test sample; (2) applying glue to the detection area of the test sample, and then applying pressure to the detection area along a first direction, so that the glue fully infiltrates the detection area; the first direction is the direction in which glue points to the detection area; the viscosity of the glue is 50 to 5000 cps, the chromaticity of the glue is 3 to 12, and the surface tension of the glue is 20 to 90 mN / m; and (3) removing the pressure, and observing the glass yarn closed channel of the detection area through a magnifying lens to obtain a detection result. Through special design of glue and design and mutual cooperation of detection steps, accurate detection of the glass yarn closed channel is realized, strong relevance is established between the glass yarn closed channel and white lines of the bonding sheet, and an accurate and effective glass fiber cloth detection and screening method is provided.

Description

Technical Field

[0001] The invention belongs to the technical field of copper clad laminates, relates to the detection of glass fiber cloth for copper clad laminates, and specifically relates to a method for detecting a glass yarn closed channel in the glass fiber cloth. Background Art

[0002] Printed circuit boards (PCBs) are important electronic materials that carry and connect electronic components, form conductive circuit patterns, and achieve insulation between layers / circuits. Copper clad laminates are important basic materials for preparing printed circuit boards, and their quality directly affects the performance of printed circuit boards.

[0003] The preparation method of copper clad laminate generally includes the following steps: using glass fiber cloth (referred to as "glass fiber cloth") and other reinforcing materials impregnated with resin glue to form a bonding sheet; stacking one or more bonding sheets, covering one or both sides with copper foil, and then hot pressing and curing to form a copper clad laminate. The quality and wetting properties of glass fiber cloth are directly related to the reliability of subsequent copper clad laminates and PCBs. Therefore, both glass fiber cloth manufacturers and copper clad laminate manufacturers attach great importance to the performance of glass fiber cloth.

[0004] White lines on the bonding sheet have a very obvious negative impact on the reliability of the board. In recent years, as the industry's requirements for the quality of copper-clad laminate products have become increasingly higher, the attention to white lines on the board has also increased, and white lines on the board are prone to appear in thin boards. As the hole spacing and hole wall spacing of PCB manufacturers continue to decrease, white lines will seriously affect the reliability of the board and bring huge quality risks. White lines on the board are relatively closely related to glass fiber cloth, but the current detection of glass fiber cloth is mainly wettability test, for example, by soaking in solutions such as benzyl alcohol and checking the penetration time of glass fiber cloth to characterize its wettability, but the wettability test results cannot reflect information related to white lines on the board, nor can they reflect information related to white lines on the bonding sheet. How to test and screen glass fiber cloth to avoid white lines on the bonding sheet still has a large gap in this field. Therefore, developing a new detection method for glass fiber cloth to provide reliable information guidance for avoiding white lines on the bonding sheet is a problem that needs to be solved in this field. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for detecting the closed channels of glass yarn in glass fiber cloth. The detection method can realize the accurate detection of the closed channels of glass yarn, and then establish a strong correlation between the closed channels of glass yarn and the white lines of bonding sheets, and propose an accurate and effective detection and screening method for glass fiber cloth, so as to provide reliable information guidance for avoiding white lines in bonding sheets.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for detecting a closed channel of glass yarn in a glass fiber cloth, the detection method comprising the following steps:

[0008] (1) Stretch the glass fiber cloth to be tested along the warp direction to obtain a test sample;

[0009] (2) after applying glue to the detection area of ​​the test sample, applying pressure to the detection area along a first direction so that the glue fully infiltrates the detection area; the first direction is the direction in which the glue points to the detection area;

[0010] The viscosity of the glue is 50-5000cps, the chroma is 3-12, and the surface tension is 20-90mN / m;

[0011] (3) removing the pressure, observing the glass yarn closed channel in the detection area through a magnifying glass, and obtaining the detection result.

[0012] After research, the present invention has found that if there is a closed channel in the glass yarn of the glass fiber cloth (referred to as "glass fiber cloth"), it will cause white line defects to form after the bonding sheet is glued. In the prior art, the test of glass fiber cloth is mainly focused on the wettability, and there is no good inspection method for the closed channels in the glass yarn. The present invention studies the inspection method for white lines in glass cloth, provides a detection method for improving the white lines in glass cloth, and proposes a detection method for the closed channels of glass yarn in glass fiber cloth. Through the selection of glue, the design of detection steps and mutual coordination, the closed channels in the glass yarn of the glass fiber cloth are revealed, and the accurate detection of the closed channels of the glass yarn is achieved. Then, a strong correlation is established between the closed channels of the glass yarn and the white lines of the bonding sheet, and an accurate and effective detection and screening method for glass fiber cloth is proposed, which provides reliable guidance for avoiding white lines in the bonding sheet.

[0013] In particular, the viscosity of the glue used in the present invention is 50-5000cps, and its fluidity is relatively good; at the same time, its chromaticity is 3-12, and the darker color is convenient for subsequent observation; the surface tension of the glue is 20-90mN / m, which can fully and effectively infiltrate and soak the glass fiber cloth to be tested. The present invention fully reveals the glass yarn closed channel in the glass fiber cloth through the special design of the glue and its coordination with the detection step, thereby achieving accurate detection.

[0014] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0015] In the present invention, the viscosity of the glue is 50-5000cps, for example, it can be 100cps, 200cps, 500cps, 800cps, 1000cps, 1200cps, 1500cps, 1800cps, 2000cps, 2200cps, 2500cps, 2800cps, 3000cps, 3200cps, 3500cps, 3800cps, 4000cps, 4200cps, 4500cps or 4800cps, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0016] The chromaticity of the glue is 3-12, for example, it can be 3.5, 4, 4.5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11 or 11.5, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0017] The surface tension of the glue is 20-90mN / m, for example, it can be 22mN / m, 25mN / m, 28mN / m, 30mN / m, 32mN / m, 35mN / m, 38mN / m, 40mN / m, 42mN / m, 45mN / m, 48mN / m, 50mN / m, 52mN / m, 55mN / m, 58mN / m, 60mN / m, 62mN / m, 65mN / m, 68mN / m, 70mN / m, 72mN / m, 75mN / m, 78mN / m, 80mN / m, 82mN / m, 85mN / m or 88mN / m, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0018] For example, the viscosity of the glue can be obtained by a rotational viscometer test at a test temperature of 25° C. The chromaticity of the glue can be obtained by a Gardner colorimeter test. The surface tension of the glue can be measured by the hanging drop method in SY / T 5370-2018.

[0019] Preferably, the warp stretching force is 5-80N, for example, it can be 8N, 10N, 15N, 20N, 25N, 30N, 35N, 40N, 45N, 50N, 55N, 60N, 65N, 70N or 75N, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0020] Preferably, the warp stretching time is 3-40s, for example, it can be 5s, 8s, 10s, 12s, 15s, 18s, 20s, 22s, 25s, 28s, 30s, 32s, 35s or 38s, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0021] It should be noted that, in the present invention, the glass fiber cloth to be tested is stretched along the warp direction, thereby causing irreversible deformation of the glass fiber cloth, which is convenient for subsequent glue infiltration and testing.

[0022] Preferably, the glue comprises epoxy resin glue.

[0023] For example, the glue can be a multifunctional epoxy resin glue, such as any one of a trifunctional epoxy resin glue and a tetrafunctional epoxy resin glue, or a combination of at least two thereof. The glue can be obtained from commercial sources, such as SQSN-4132A70 from Shandong Shengquan, TNE190A70 from Changchun, Taiwan, China, and the like.

[0024] Preferably, the solid content of the glue is 50-80%, for example, it can be 52%, 55%, 58%, 60%, 62%, 65%, 68%, 70%, 72%, 75% or 78%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0025] Preferably, the area of ​​the detection area is 20-50 cm 2 ; For example, it can be 22cm 2 、25cm 2 、28cm 2 、30cm 2 、32cm 2 、35cm 2 、38cm 2 、40cm 2 、42cm 2 、45cm 2 or 48cm 2 , as well as specific point values ​​between the above point values, due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0026] Preferably, the amount of glue applied is 10-60 mg / cm 2 , for example, 12 mg / cm 2 、15mg / cm 2 、18mg / cm 2 , 20mg / cm 2 , 22mg / cm2 , 25mg / cm 2 、28mg / cm 2 、30mg / cm 2 、32mg / cm 2 、35mg / cm 2 、38mg / cm 2 , 40mg / cm 2 , 42mg / cm 2 , 45mg / cm 2 , 48mg / cm 2 、50mg / cm 2 , 52mg / cm 2 、55mg / cm 2 or 58 mg / cm 2 , as well as specific point values ​​between the above point values, due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0027] As a preferred technical solution of the present invention, by controlling the amount of glue applied in the detection area per unit area within a preferred range, the glass fiber cloth in the detection area can be fully infiltrated and soaked with glue, which is more conducive to the visualization of the glass yarn closed channel.

[0028] Preferably, the method of applying pressure includes placing weights; that is, the method of applying pressure includes: placing weights above the detection area after the glue is applied (also above the glue), thereby applying pressure along a first direction to the detection area, and applying pressure can further ensure that the glue fully infiltrates and penetrates the detection area, avoiding the problem of poor infiltration caused by capillary phenomena.

[0029] Preferably, the mass of the weight is 1-5kg, for example, it can be 1.2kg, 1.5kg, 1.8kg, 2kg, 2.2kg, 2.5kg, 2.8kg, 3kg, 3.5kg, 4kg or 4.5kg, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, and 1.5-3kg is further preferred.

[0030] Preferably, the time for applying pressure is 3-40s, for example, it can be 5s, 8s, 10s, 12s, 14s, 15s, 16s, 18s, 20s, 22s, 25s, 28s, 30s, 32s, 35s or 38s, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, and 5-20s is further preferred.

[0031] Preferably, after removing the pressure (before observing through a magnifying glass), the method further includes scraping the glue in the detection area flat.

[0032] Preferably, the magnifying glass is an electron microscope magnifying glass with a light source.

[0033] Preferably, the detection area is placed on an inspection platform of an electron microscope, the electron microscope is adjusted to make the detection area clear, the glass yarn closed channel of the detection area is observed, and the length of the glass yarn closed channel is tested.

[0034] Preferably, adjusting the electronic microscope magnifier includes at least one of adjusting the magnification, adjusting the focal length, and adjusting the brightness of the light source to make the field of view of the detection area clear.

[0035] In the detection method of the present invention, the glass yarn closed channel is generally in a straight line long strip whitish state with white warp edges, and its exemplary test diagram is as follows Figure 1 As shown, the circled position is the observed glass yarn closed channel.

[0036] Preferably, the detection method comprises the following steps:

[0037] (1) stretching the glass fiber cloth to be tested along the warp direction with a force of 5-80 N and a time of 3-40 s to obtain a test sample;

[0038] (2) after applying glue to the detection area of ​​the test sample, applying pressure to the detection area along a first direction so that the glue fully infiltrates the detection area; the first direction is the direction in which the glue points to the detection area;

[0039] The viscosity of the glue is 50-5000cps, the chromaticity is 3-12, and the surface tension is 20-90mN / m; the area of ​​the detection area is 20-50cm 2 The amount of glue applied is 10-60 mg / cm 2 ;

[0040] The method of applying pressure is to place a weight of 1-5 kg ​​in the detection area, and the time of applying pressure is 3-40 seconds;

[0041] (3) Remove the weight, scrape the glue on the test area flat, place it on the inspection platform of the electron microscope, adjust the electron microscope to make the test area clear, observe the glass yarn closed channel in the test area, and test the length of the glass yarn closed channel to obtain the test result.

[0042] As a preferred technical solution of the present invention, in the test results obtained by the detection method, the glass yarn closed channels are generally in a white state with whitish edges of the warp yarn and in a straight and long white strip shape; the number of glass yarn closed channels is strongly correlated with the number of white lines on the bonding sheet, and the maximum length of the glass yarn closed channels is strongly correlated with the maximum length of the white lines on the bonding sheet; the test results can be used as one of the screening criteria for glass fiber cloth to provide reliable information guidance for avoiding white lines on the bonding sheet.

[0043] In a second aspect, the present invention provides an application of the detection method as described in the first aspect in the screening of reinforcing materials for copper clad laminates or the preparation of copper clad laminates.

[0044] Preferably, the detection method is applied to the screening of glass fiber cloth for copper clad laminates.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] In the method for detecting the closed channels of glass yarn in glass fiber cloth provided by the present invention, the closed channels in the glass yarn of the glass fiber cloth are fully revealed through the special design of glue, the design of the detection steps and their mutual coordination, thereby realizing the accurate detection of the closed channels of the glass yarn, and then establishing a strong correlation between the closed channels of the glass yarn and the white lines of the bonding sheet, and proposing an accurate and effective method for detecting and screening glass fiber cloth, thereby providing a reliable basis for avoiding the white lines of the bonding sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a test diagram of a glass yarn closed channel obtained by testing the detection method of Example 1 of the present invention;

[0048] Figure 2 A schematic diagram of white lines on the adhesive sheet after the glass yarn closed channel is glued and dried, obtained by the detection method provided in Example 1 of the present invention;

[0049] Figure 3 This is a SEM test image of a slice of the glass yarn closed channel pressing plate after curing obtained by the detection method provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0051] In the following specific embodiments of the present invention, the glues involved are all commercially available chemicals, and the specific information is as follows:

[0052] serial number Viscosity(cps) Chroma Surface tension (mN / m) Glue A1 150 11 74 Glue A2 2500 5 32 Glue D1 180 2 82 Glue D2 140 14 67 Glue D3 2200 8 102 Glue D4 2300 7 13 Glue D5 34 10 65 Glue D6 5200 6 39

[0053] The viscosity of the glue is measured by a rotational viscometer at a test temperature of 25°C. The chromaticity of the glue is measured by a Gardner colorimeter. The surface tension of the glue is measured by the hanging drop method in SY / T 5370-2018.

[0054] The following will take multiple embodiments as examples to describe in detail the method for detecting the closed channel of glass yarn in the glass fiber cloth of the present invention, but the detection method of the present invention is not limited to these embodiments.

[0055] Example 1

[0056] A method for detecting a glass yarn closed channel in a glass fiber cloth comprises the following steps:

[0057] (1) Stretch the glass fiber cloth to be tested along the warp direction with a force of 50 N and a time of 15 s to obtain a test sample;

[0058] (2) Place a release film on the glass platform, place the test sample on the release film, and drip glue A1 on the test area. The area of ​​the test area is 30 cm 2 , the amount of glue A1 added is 1g; then a 2kg weight is placed above the detection area (above glue A1) to apply pressure so that glue A1 fully infiltrates the detection area, and the pressure is applied for 10s;

[0059] (3) After removing the weight, the glue in the test area is scraped flat with a ceramic sheet, and then the test area is placed on the inspection platform of the electron microscope. The magnification of the electron microscope is adjusted to 50×, and the focus knob and the brightness of the electron microscope light source are adjusted until the field of view of the test area of ​​the sample is clear. The glass yarn closed channel in the test area is observed, and the warp yarn edges are whitish and the straight and long strips are whitish, as shown in FIG. Figure 1 As shown, the circled position is the glass yarn closed channel; and the length of the glass yarn closed channel is tested to obtain the test result.

[0060] The detection method provided in this embodiment was used to detect glass fiber cloths of different batches (Batch 1-2), and the white lines of the adhesive sheet made of the glass fiber cloth were detected accordingly. The obtained data are shown in Table 1.

[0061] The bonding sheet made of glass fiber cloth tested by the testing method provided in this embodiment is observed and measured by a magnifying glass. Figure 2 As shown, the white lines on the bonding sheet and the specific length of the white lines can be accurately seen; the bonding sheet is further pressed and solidified, slices are made, and the morphology of the slices is observed using a scanning electron microscope (SEM). The obtained SEM test image is as follows Figure 3As shown, it can be accurately seen that the closed channel of the glass yarn is at the edge of the warp yarn, and there is a resin cavity between the two warp yarns.

[0062] Example 2

[0063] A method for detecting a glass yarn closed channel in a glass fiber cloth comprises the following steps:

[0064] (1) Stretch the glass fiber cloth to be tested along the warp direction with a force of 30 N and a time of 20 s to obtain a test sample;

[0065] (2) Place a release film on the glass platform, place the test sample on the release film, and drip glue A2 on the test area. The area of ​​the test area is 30 cm 2 , the amount of glue A2 added is 1g; then a 3kg weight is placed above the detection area (above glue A2) to apply pressure so that the glue A2 fully infiltrates the detection area, and the pressure is applied for 15s;

[0066] (3) After removing the weight, the glue in the test area is scraped flat with a ceramic sheet, and then the sample is placed on the inspection platform of an electron microscope. The magnification of the electron microscope is adjusted to 50×, the focus knob and the brightness of the electron microscope light source are adjusted until the field of view of the test area of ​​the sample is clear, and the glass yarn closed channel in the test area is observed.

[0067] The detection method provided in this embodiment was used to detect glass fiber cloths of different batches (batches 3-4), and the white lines of the bonding sheets made of the glass fiber cloths were detected accordingly. The obtained data are shown in Table 1.

[0068] Table 1

[0069]

[0070] In Table 1, the testing method for the number and length of white lines of the bonding sheet is: observing and recording the number of white lines through a magnifying glass, and performing a length test.

[0071] It can be seen from Table 1 that there is a strong correlation between the number of glass yarn closed channels and the number of white lines on the bonding sheet, and between the maximum length of the glass yarn closed channels and the maximum length of the white lines on the bonding sheet, which proves that the detection method of the present invention is feasible and the test results are accurate.

[0072] Comparative Example 1

[0073] (1) Stretch the glass fiber cloth to be tested along the warp direction with a force of 50 N and a time of 15 s to obtain a test sample;

[0074] (2) Place a release film on the glass platform, place the test sample on the release film, and drip glue D1 on the test area. The area of ​​the test area is 30 cm 2 The amount of glue D1 added is 1 g; then a 2 kg weight is placed above the detection area (above the glue D1) to apply pressure so that the glue D1 fully infiltrates the detection area, and the pressure is applied for 10 seconds;

[0075] (3) After removing the weight, the glue in the test area is scraped flat with a ceramic sheet, and then the sample is placed on the inspection platform of an electron microscope. The magnification of the electron microscope is adjusted to 50×, the focus knob and the brightness of the electron microscope light source are adjusted until the field of view of the test area of ​​the sample is clear, and the glass yarn closed channel in the test area is observed.

[0076] The detection method provided in this comparative example was used to detect glass fiber cloths of different batches (Batch 1-2), and the white lines of the bonding sheet made of the glass fiber cloth were detected accordingly. The obtained data are shown in Table 2.

[0077] Comparative Example 2

[0078] A method for detecting a closed channel of glass yarn in a glass fiber cloth, which differs from Comparative Example 1 only in that glue D1 is replaced by glue D2, and other parameters are the same as those of Comparative Example 1. The detection method provided in this comparative example is used to detect glass fiber cloths of different batches (batches 3-4), and the white lines of the bonding sheet made of the glass fiber cloth are detected accordingly, and the obtained data are shown in Table 2.

[0079] Comparative Example 3

[0080] A method for detecting a closed channel of glass yarn in a glass fiber cloth, which differs from Comparative Example 1 only in that glue D1 is replaced by glue D3, and other parameters are the same as those of Comparative Example 1. The detection method provided in this comparative example is used to detect glass fiber cloths of different batches (batches 1-2), and the white lines of the bonding sheet made of the glass fiber cloth are detected accordingly, and the obtained data are shown in Table 2.

[0081] Comparative Example 4

[0082] A method for detecting a glass yarn closed channel in a glass fiber cloth, which differs from Comparative Example 1 only in that glue D1 is replaced by glue D4, and other parameters are the same as those of Comparative Example 1. The detection method provided in this comparative example is used to detect glass fiber cloths of different batches (batches 3-4), and the white lines of the bonding sheet made of the glass fiber cloth are detected accordingly, and the obtained data are shown in Table 3.

[0083] Comparative Example 5

[0084] A method for detecting a closed channel of glass yarn in a glass fiber cloth, which differs from Comparative Example 1 only in that glue D1 is replaced by glue D5, and other parameters are the same as those of Comparative Example 1. The detection method provided in this comparative example is used to detect glass fiber cloths of different batches (batches 1-2), and the white lines of the bonding sheet made of the glass fiber cloth are detected accordingly, and the obtained data are shown in Table 3.

[0085] Comparative Example 6

[0086] A method for detecting a closed channel of glass yarn in a glass fiber cloth, which differs from Comparative Example 1 only in that glue D1 is replaced by glue D6, and other parameters are the same as those of Comparative Example 1. The detection method provided in this comparative example is used to detect glass fiber cloths of different batches (batches 3-4), and the white lines of the bonding sheet made of the glass fiber cloth are detected accordingly, and the obtained data are shown in Table 3.

[0087] Table 2

[0088]

[0089] Table 3

[0090]

[0091] It can be seen from Tables 2-3 that when the glue viscosity, chromaticity and surface tension used in Comparative Examples 1-6 are not within the range defined by the present invention, the glass yarn closed channel cannot be effectively observed, but white lines still exist in the corresponding bonding sheet, indicating that the glass yarn closed channel can only be effectively observed by controlling the glue viscosity, chromaticity and surface tension.

[0092] Comparative Example 7

[0093] A method for detecting a closed channel of glass yarn in a glass fiber cloth, which differs from Example 1 only in that the glass fiber cloth to be tested has not been stretched in the warp direction, and other parameters are the same as those of Example 1. The detection method provided in this comparative example is used to detect glass fiber cloths of different batches (batches 1-2), and the white lines of the bonding sheet made of the glass fiber cloth are detected accordingly, and the obtained data are shown in Table 4.

[0094] Comparative Example 8

[0095] A method for detecting a closed channel of glass yarn in a glass fiber cloth, which differs from Example 1 only in that no pressure is applied above the detection area of ​​the glass fiber cloth after glue is dripped on the detection area, and other parameters are the same as those of Example 1. The detection method provided in this comparative example is used to detect glass fiber cloths of different batches (batches 1-2), and the white lines of the bonding sheet made of the glass fiber cloth are detected accordingly, and the obtained data are shown in Table 4.

[0096] Table 4

[0097]

[0098] It can be seen from Table 4 that the glass fiber cloth of Comparative Example 7 was not stretched in the warp direction, and no pressure was applied to the detection area of ​​Comparative Example 8, resulting in a decrease in the observable glass yarn closed channels compared to Example 1.

[0099] The applicant declares that the present invention illustrates the detection method of the glass yarn closed channel in the glass fiber cloth of the present invention through the above-mentioned embodiment, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for detecting a closed channel of glass yarn in a glass fiber cloth, characterized in that: The detection method comprises the following steps: (1) Stretch the glass fiber cloth to be tested along the warp direction to obtain a test sample; (2) after applying glue to the detection area of ​​the test sample, applying pressure to the detection area along a first direction so that the glue fully infiltrates the detection area; the first direction is the direction in which the glue points to the detection area; The viscosity of the glue is 50-5000cps, the chroma is 3-12, and the surface tension is 20-90mN / m; (3) removing the pressure, observing the glass yarn closed channel in the detection area through a magnifying glass, and obtaining the detection result.

2. The detection method according to claim 1, characterized in that: The warp stretching force is 5-80N; Preferably, the warp stretching time is 3-40s.

3. The detection method according to claim 1 or 2, characterized in that: The glue includes epoxy resin glue; Preferably, the area of ​​the detection area is 20-50 cm 2 ; Preferably, the amount of glue applied is 10-60 mg / cm 2 .

4. The detection method according to any one of claims 1 to 3, characterized in that: The method of applying pressure includes placing weights; Preferably, the mass of the weight is 1-5 kg, more preferably 1.5-3 kg.

5. The detection method according to any one of claims 1 to 4, characterized in that: The time for applying pressure is 3-40s, preferably 5-20s.

6. The detection method according to any one of claims 1 to 5, characterized in that: After removing the pressure, the method further includes the step of flattening the glue in the detection area.

7. The detection method according to any one of claims 1 to 6, characterized in that: The magnifying glass is an electronic microscope magnifying glass with a light source.

8. The detection method according to claim 7, characterized in that: The detection area is placed on the inspection platform of an electron microscope, the electron microscope is adjusted to make the detection area clear, the glass yarn closed channel of the detection area is observed, and the length of the glass yarn closed channel is tested.

9. The detection method according to claim 1, characterized in that: The detection method comprises the following steps: (1) stretching the glass fiber cloth to be tested along the warp direction with a force of 5-80 N and a time of 3-40 s to obtain a test sample; (2) after applying glue to the detection area of ​​the test sample, applying pressure to the detection area along a first direction so that the glue fully infiltrates the detection area; the first direction is the direction in which the glue points to the detection area; The viscosity of the glue is 50-5000cps, the chromaticity is 3-12, and the surface tension is 20-90mN / m; the area of ​​the detection area is 20-50cm 2 The amount of glue applied is 10-60 mg / cm 2 ; The method of applying pressure is to place a weight of 1-5 kg ​​in the detection area, and the time of applying pressure is 3-40 seconds; (3) Remove the weight, scrape the glue on the test area flat, place it on the inspection platform of the electron microscope, adjust the electron microscope to make the test area clear, observe the glass yarn closed channel in the test area, and test the length of the glass yarn closed channel to obtain the test result.

10. Use of the detection method according to any one of claims 1 to 9 in the screening of reinforcing materials for copper clad laminates or in the preparation of copper clad laminates.

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