Chemical desizing agent for electronic glass fabric as well as preparation method and application of chemical desizing agent

Abstract

The invention relates to a chemical desizing agent for electronic glass fabric as well as a preparation method and application of the chemical desizing agent, and belongs to the technical field of treatment of glass fabric. The chemical desizing agent for the electronic glass fabric comprises water and a water-soluble oligomer, the water-soluble oligomer is composed of a main chain and a side chain, the main chain is a carbon chain with the molecular weight of 300-400, and the side chain comprises hydroxyl, amino and sulfydryl; the mass fraction of the water-soluble oligomer in the chemical desizing agent for the electronic glass fabric is 30%-50%. According to the chemical desizing agent, an impregnating compound and a secondary sizing agent on the electronic glass fabric can be efficiently separated from the fabric surface at normal temperature, so that the electronic glass fabric has good impregnation property and excellent tensile strength.

Description

Technical Field

[0001] The invention relates to the technical field of glass fiber fabric processing, and in particular to a chemical desizing agent for electronic glass fiber cloth, and a preparation method and application thereof. Background Art

[0002] Electronic glass fiber cloth is woven from glass fiber yarn with a single filament diameter of less than 9 microns. It has excellent electrical insulation, weather resistance and chemical corrosion resistance, and is one of the main materials used to prepare printed circuit boards. After the electronic glass fiber cloth is woven, the sizing agent used to provide excellent textile properties and the sizing agent for secondary sizing of the warp yarn need to be removed to avoid affecting the impregnation of the electronic glass fiber cloth during post-processing and its bonding performance with the resin.

[0003] At present, thermal desizing is often used to remove the sizing agent or sizing agent on the surface of electronic glass fiber cloth. The traditional thermal desizing method mainly uses high temperature to thermally decompose the sizing agent and secondary sizing agent on the surface of electronic glass fiber cloth under high temperature conditions. The process mainly includes 1) rapid continuous desizing KH: using high temperature (about 400°C) to remove about 90% of organic matter on the cloth surface; 2) intermittent batch desizing BH: also carried out at high temperature (about 400°C), but it takes a longer time (generally more than 40 hours), the purpose is to remove all remaining sizing agents and make the cloth surface cleaner.

[0004] However, the above-mentioned thermal desizing method has many disadvantages, such as 1) high temperature, long time, high energy consumption and high cost; 2) the thermal desizing effect is limited, there are still residues on the cloth surface, the whiteness of the cloth surface color is low and the hot air easily causes wrinkles; 3) after the secondary high temperature treatment, the strength of the electronic fiberglass cloth is low, and it is easy to break the cloth when it is used as a reinforcing material for copper clad laminates. In addition, with the light, thin, short, small and high-density assembly of electronic products, printed circuit boards are rapidly developing in the direction of multi-layer and super-multi-layer, which requires the electronic fiberglass cloth to develop in the direction of thin or ultra-thin.

[0005] Compared with conventional electronic fiberglass cloth, the warp and weft yarns of ultra-thin electronic fiberglass cloth are thinner, and the warp and weft are arranged more tightly, which requires higher desizing. The traditional thermal desizing method not only easily causes wrinkles in the electronic fiberglass cloth, but also causes a large loss of its strength, making it difficult to meet the requirements of ultra-thin electronic fiberglass cloth. In addition, the residual amount of low-dielectric (Low DK) electronic fiberglass cloth after the traditional thermal desizing process is very high (about 0.5% to 0.8%), resulting in the residue occupying a large part of the glass fiber surface, which seriously affects the bonding between the glass fiber surface and the coupling agent, and further affects the performance of the PCB board made of Low DK electronic fiberglass cloth. In particular, the second-generation low-dielectric (Low DK) electronic thin cloth usually warps or wrinkles after the traditional thermal desizing process, which is a difficult problem in the development and production process of the second-generation Low DK electronic thin cloth. It is necessary to explore new desizing processes to solve the problem of warping or wrinkling.

[0006] In order to improve the quality of electronic glass fiber cloth after desizing, people began to improve the thermal desizing process or explore other desizing methods. Chinese patent document (CN102926183A) discloses an application of an additive in the desizing of electronic-grade glass fiber cloth and its desizing process, which uses a calcium compound as a desizing additive combined with a two-stage smoldering desizing process. By adding a desizing additive containing a calcium compound, it promotes the decomposition and gasification of the slurry on the surface of the electronic-grade glass fiber cloth during the smoldering process. Although this method can increase the whiteness of the electronic cloth after desizing and reduce the residual amount, the addition of calcium compounds increases the ash content.

[0007] In addition, the Chinese patent document (CN113957701A) also discloses a water-soluble one-step desizing liquid for ultra-thin electronic-grade glass fiber cloth and a preparation method. Although the desizing liquid is conducive to promoting the slurry infiltration and swelling of the surface of the electronic glass fiber cloth, and then separating from the cloth surface to reduce the slurry residue; however, the main components of the desizing liquid are hydrogen peroxide, alkali, stabilizer, etc. The reaction of hydrogen peroxide takes a long time, and the metal ions contained in the stabilizer and the alkali solution are prone to form metal ion ash residues, which in turn affects the combination of the electronic glass fiber cloth and the resin and leads to a decrease in electrical insulation performance. Therefore, it is urgent to develop a new desizing method with high desizing efficiency and suitable for mass production. Summary of the invention

[0008] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an electronic glass fiber cloth chemical desizing agent and a preparation method and application thereof.

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] In a first aspect, the present invention provides a chemical desizing agent for electronic glass fiber cloth, which includes water and water-soluble oligomers; the water-soluble oligomers are composed of a main chain and a side chain, the main chain is a carbon chain with a molecular weight of 300 to 400, and the side chain contains a hydroxyl group, an amino group and a thiol group; the mass fraction of the water-soluble oligomers in the chemical desizing agent for electronic glass fiber cloth is 30% to 50%.

[0011] The electronic glass fiber cloth chemical desizing agent of the present invention comprises a water-soluble oligomer and water, wherein the water-soluble oligomer consists of a main chain (short carbon chain) and a side chain connected to the main chain and comprising a hydroxyl group, an amino group and a thiol group, the main chain has a suitable molecular weight, so that its aqueous solution is stable and has suitable permeability, and is easy to penetrate the electronic cloth during implementation, and the side chain contains a hydroxyl group, an amino group and a thiol group, so that the oligomer is easily soluble in water and is easy to form hydrogen bonds such as hydroxyl-hydroxyl, hydroxyl-amino, hydroxyl-thiol, etc., which can destroy the hydrogen bonds between starch molecules and make the starch structure loose, so that the electronic glass fiber cloth can remove the wetting agent and the secondary sizing agent (mainly composed of starch) on the surface of the electronic glass fiber cloth at room temperature, so that the treated electronic glass fiber cloth maintains excellent tensile strength and has good impregnation.

[0012] Optionally, the mass fraction of the water-soluble oligomer in the chemical desizing agent for electronic glass fiber cloth can be any one of 30%, 35%, 40%, 45%, 50% or any two of them. Studies have found that when the mass fraction of the water-soluble oligomer in the chemical desizing agent for electronic glass fiber cloth is too large or too small, it is not conducive to the penetration of the water-soluble oligomer in the electronic cloth.

[0013] Optionally, the molecular weight of the main chain (short carbon chain) in the water-soluble oligomer can be any one or any two of 300, 310, 320, 330, 340, 350. Studies have shown that the molecular weight of the main chain in the water-soluble oligomer affects the water-soluble stability of the oligomer. If the molecular weight is too high, its water solubility will deteriorate.

[0014] As a preferred embodiment of the chemical desizing agent for electronic glass fiber cloth of the present invention, the mass fraction of the water-soluble oligomer in the chemical desizing agent for electronic glass fiber cloth is 35% to 45%, preferably 38% to 40%.

[0015] As a preferred embodiment of the chemical desizing agent for electronic glass fiber cloth of the present invention, the main chain in the water-soluble oligomer is a carbon chain with a molecular weight of 305-350.

[0016] As a preferred embodiment of the chemical desizing agent for electronic glass fiber cloth of the present invention, the mass percentage of hydroxyl groups in the water-soluble oligomer is 0.8% to 1.2%. Optionally, the mass percentage of hydroxyl groups in the water-soluble oligomer can be any one of 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, or any two of them.

[0017] As a preferred embodiment of the chemical desizing agent for electronic glass fiber cloth of the present invention, the mass percentage of amino groups in the water-soluble oligomer is 6.0% to 7.0%. Optionally, the mass percentage of amino groups in the water-soluble oligomer can be any one of 6.0%, 6.2%, 6.4%, 6.6%, 6.8%, 7.0%, or any two of the range values.

[0018] As a preferred embodiment of the chemical desizing agent for electronic glass fiber cloth of the present invention, the mass percentage of thiol in the water-soluble oligomer is 0.6% to 0.8%. Optionally, the mass percentage of thiol in the water-soluble oligomer can be any one of 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, or any two of them.

[0019] The mass percentage of hydroxyl, amino or thiol in the water-soluble oligomer can be determined by hydrogen nuclear magnetic resonance spectroscopy.

[0020] In a second aspect, the present invention provides a method for preparing the chemical desizing agent for electronic glass fiber cloth, comprising the following steps: dissolving a water-soluble oligomer in water to obtain the chemical desizing agent for electronic glass fiber cloth.

[0021] In a third aspect, the present invention provides the use of the above-mentioned chemical desizing agent for electronic glass fiber cloth in a continuous production desizing process.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention uses an aqueous solution of a specific water-soluble oligomer as a chemical desizing agent for electronic glass fiber cloth, which does not contain metal ions and does not bring additional ash. Moreover, the sizing agent and secondary sizing agent on the electronic glass fiber cloth can be efficiently separated from the cloth surface by soaking at room temperature without high temperature or other special conditions, and the treated electronic glass fiber cloth has good impregnation and excellent tensile strength, which can meet the requirements of continuous production desizing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a photograph of a sample completely immersed in a benzyl alcohol solution in the impregnation test of the present invention;

[0025] Figure 2 This is a photograph of the position of the sample measured by naked eye in the impregnation test of the present invention (left);

[0026] Figure 3 This is a photograph of the position of the sample (middle) measured by naked eye in the impregnation test of the present invention;

[0027] Figure 4 This is a photograph of the sample position (right) measured by naked eye in the impregnation test of the present invention. DETAILED DESCRIPTION

[0028] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0029] Unless otherwise specified, other materials, reagents, etc. used in the examples can be obtained from commercial sources.

[0030] Water-soluble oligomer 1, the main chain is a short carbon chain with a molecular weight of 305, the manufacturer is Axioma Enterprise LLC;

[0031] Water-soluble oligomer 2, the main chain is a short carbon chain with a molecular weight of 345, brand DS670, manufacturer Xi'an Zhiming Xinliang Biotechnology Co., Ltd.

[0032] Example 1

[0033] An embodiment of the chemical desizing agent for electronic glass fiber cloth of the present invention comprises a water-soluble oligomer 1 and water, wherein the mass fraction of the water-soluble oligomer 1 is 38%.

[0034] The preparation method of the chemical desizing agent for electronic glass fiber cloth comprises the following steps: dissolving a water-soluble oligomer in water to obtain the chemical desizing agent for electronic glass fiber cloth.

[0035] E glass fiber cloth (1080 cloth) was used as electronic glass fiber cloth (secondary sizing was starch-based secondary sizing) and was subjected to chemical desizing treatment and conventional thermal desizing treatment respectively;

[0036] Experimental group (chemical desizing - can be performed continuously): the above-mentioned electronic glass fiber cloth chemical desizing agent and the desizing device in Example 1 of the prior art CN218812619U (2022229763222 - a desizing device for electronic glass fiber cloth) were used for desizing treatment, and then deionized water was used for washing (the running speed of the electronic glass fiber cloth was 10m / min and the water spunlace pressure was 3kg) to obtain the desized electronic glass fiber cloth, and then a coupling agent (Dow Corning 6032) was used to surface treat the desized electronic glass fiber cloth to obtain a surface-treated electronic glass fiber cloth A;

[0037] Control group (conventional thermal desizing-intermittent): The electronic glass fiber cloth was first desized by conventional KH desizing (continuous calcination at 410°C process) and BH secondary desizing (calcination at 410°C for 45h) processes to obtain the desized electronic glass fiber cloth, and then the desized electronic glass fiber cloth was surface treated with a coupling agent (Dow Corning 6032) to obtain surface-treated electronic glass fiber cloth B.

[0038] The desized electronic glass fiber cloth and the surface treated electronic glass fiber cloth were respectively subjected to combustible content test, and the surface treated electronic glass fiber cloth was respectively subjected to warp yarn width test, air permeability test, impregnation test and tensile strength test. The specific test methods are shown below, and the test results are shown in Table 1.

[0039] 1) Combustible content (LOI): Determined in accordance with standard GB / T 9914.2-2001;

[0040] 2) Warp yarn width: measured according to standard T / STIC110088-2023;

[0041] 3) Air permeability: measured according to standard SJ21286-2018;

[0042] 4) Impregnation: Determined according to the electronic cloth penetration time test specification, specifically including the following steps:

[0043] S1. Add an appropriate amount of benzyl alcohol (about 500-600 mL) into a transparent glass container (length 50 cm, width 15 cm, height 5 cm);

[0044] S2, take 3 samples (length 10cm, width 7.5cm) from different positions of the surface treated electronic glass fiber cloth, record them as X1, X2, X3 respectively; then place X1, X2 and X3 on the liquid surface of benzyl alcohol in S1 in the order of left, middle and right, so that the samples are completely immersed in the benzyl alcohol solution (such as Figure 1 As shown), the timing starts immediately;

[0045] S3. The observer stands beside the transparent glass container and uses a light source (which can be a flashlight) placed about 5 to 7 cm away from the transparent glass container to observe the sample with the naked eye (such as Figure 2 , Figure 3 and Figure 4 The time required for the sample to be completely immersed in the benzyl alcohol solution until the warp and weft yarns of the sample are completely soaked in benzyl alcohol is used to evaluate the warp impregnation and weft impregnation.

[0046] 5) Tensile strength: measured in accordance with standard SJ21286-2018.

[0047] Table 1

[0048] physical properties Control group B Experimental Group A Desizing LOI (%) 0.07 0.05 LOI after surface treatment (%) 0.092 0.088 Warp yarn width (μm) 334 379 <![CDATA[Air permeability (cm 3 / cm 2 / s)]]> 29.2 11.7 Longitudinal impregnation (min) 8.9 7.5 Weft impregnation (min) 2.5 1.2 Warp tensile strength (N / 25mm) 168 183 Weft tensile strength (N / 25mm) 101 152

[0049] According to the data in Table 1, the residual amount of 1080 cloth after chemical desizing treatment with the chemical desizing agent for electronic glass fiber cloth in Example 1 is 0.05%, which meets the desizing requirements of 1080 cloth. Moreover, compared with conventional thermal desizing treatment, the warp yarn width of 1080 cloth after desizing treatment with the chemical desizing agent for electronic glass fiber cloth of the present invention is increased by 13.5%, the air permeability is reduced by 60%, the warp impregnation is increased by 15%, the weft impregnation is increased by 50%, the warp tensile strength is increased by 9%, and the weft tensile strength is increased by 50%.

[0050] Example 2

[0051] An embodiment of the chemical desizing agent for electronic glass fiber cloth of the present invention comprises a water-soluble oligomer 1 and water, wherein the mass fraction of the water-soluble oligomer 1 is 38%.

[0052] The preparation method of the chemical desizing agent for electronic glass fiber cloth comprises the following steps: dissolving a water-soluble oligomer in water to obtain the chemical desizing agent for electronic glass fiber cloth.

[0053] Low dielectric (LDK) 2116 cloth was used as electronic glass fiber cloth (secondary sizing was starch-based secondary sizing) and chemical desizing and conventional thermal desizing were performed respectively;

[0054] Experimental group (chemical desizing - can be performed continuously): the above-mentioned electronic glass fiber cloth chemical desizing agent and the desizing device in Example 1 of the prior art CN218812619U (2022229763222 - a desizing device for electronic glass fiber cloth) were used for desizing treatment, and then deionized water was used for washing (the running speed of the electronic glass fiber cloth was 10m / min and the water spunlace pressure was 3kg) to obtain the desized electronic glass fiber cloth, and then a coupling agent (Dow Corning 6032) was used to surface treat the desized electronic glass fiber cloth to obtain a surface-treated electronic glass fiber cloth C;

[0055] Control group (conventional thermal desizing-intermittent): The electronic glass fiber cloth was first desized by conventional KH desizing (continuous calcination at 410°C process) and BH secondary desizing (calcination at 410°C for 45h) processes to obtain the desized electronic glass fiber cloth, and then the desized electronic glass fiber cloth was surface treated with a coupling agent (Dow Corning 6032) to obtain surface-treated electronic glass fiber cloth D.

[0056] The surface treated electronic glass fiber cloth was subjected to combustible content test, warp yarn width test, air permeability test, impregnation test and tensile strength test respectively. The specific test methods were the same as those in Example 1. The test results are shown in Table 2.

[0057] Table 2

[0058] physical properties Control group D Experimental Group C Desizing LOI (%) 0.70 0.15 Warp yarn width (μm) 343 399 <![CDATA[Air permeability (cm 3 / cm 2 / s)]]> 12.6 4.76 Longitudinal impregnation (min) 27 17 Weft impregnation (min) 14 13 Warp tensile strength (N / 25mm) 166 276 Weft tensile strength (N / 25mm) 163 256

[0059] According to the data in Table 2, the residual amount of low dielectric 2116 cloth after chemical desizing treatment with the chemical desizing agent for electronic glass fiber cloth in Example 2 is 0.15%, which is much less than the residual amount of conventional thermal desizing treatment (0.70%). Moreover, compared with conventional thermal desizing treatment, the warp yarn width of low dielectric 2116 cloth after desizing treatment with the chemical desizing agent for electronic glass fiber cloth of the present invention is increased by 16.3%, the air permeability is reduced by 62%, the warp impregnation is increased by 37%, the warp tensile strength is increased by 66%, and the weft tensile strength is increased by 57%.

[0060] At present, the residual amount of the electronic glass fiber cloth obtained by the traditional desizing process (i.e. the conventional thermal desizing treatment mentioned above) of Low DK (low dielectric) electronic glass fiber cloth is about 0.5% to 0.8%. The high residual amount may be due to the fact that the sizing agent is firmly bonded to the surface of the Low DK glass fiber and is difficult to remove by thermal desizing. The high residual amount after thermal desizing will greatly reduce the remaining active area on the surface of the glass fiber, which may affect the bonding between the glass fiber surface and the coupling agent, and further affect the bonding with the epoxy resin, resulting in poor performance of the Low DK electronic glass fiber cloth. However, the residual amount after water washing by the chemical desizing treatment of the present invention is only 0.15%, which can enhance the bonding between the glass fiber and the resin, thereby significantly improving the performance of the Low DK electronic glass fiber cloth.

[0061] Example 3

[0062] An embodiment of the chemical desizing agent for electronic glass fiber cloth of the present invention comprises a water-soluble oligomer 2 and water, wherein the mass fraction of the water-soluble oligomer 2 is 40%.

[0063] The preparation method of the chemical desizing agent for electronic glass fiber cloth comprises the following steps: dissolving a water-soluble oligomer in water to obtain the chemical desizing agent for electronic glass fiber cloth.

[0064] 106 cloth (imitating 1080) was used as electronic glass fiber cloth (secondary sizing was starch-based secondary sizing) and was subjected to chemical desizing treatment and conventional thermal desizing treatment respectively;

[0065] Experimental group (chemical desizing - can be performed continuously): the above-mentioned electronic glass fiber cloth chemical desizing agent and the desizing device in Example 1 of the prior art CN218812619U (2022229763222 - a desizing device for electronic glass fiber cloth) were used for desizing treatment, and then deionized water was used for washing (the running speed of the electronic glass fiber cloth was 10m / min and the water spunlace pressure was 3kg) to obtain the desized electronic glass fiber cloth, and then a coupling agent (Dow Corning 6032) was used to surface treat the desized electronic glass fiber cloth to obtain a surface-treated electronic glass fiber cloth E;

[0066] Control group (conventional thermal desizing-intermittent): The electronic glass fiber cloth was first desized by conventional KH desizing (continuous calcination at 410°C process) and BH secondary desizing (calcination at 410°C for 45h) processes to obtain the desized electronic glass fiber cloth, and then the desized electronic glass fiber cloth was surface treated with a coupling agent (Dow Corning 6032) to obtain surface-treated electronic glass fiber cloth F.

[0067] The surface treated electronic glass fiber cloth was subjected to combustible content test, warp yarn width test, air permeability test, impregnation test and tensile strength test respectively. The specific test methods were the same as those in Example 1. The test results are shown in Table 3.

[0068] Table 3

[0069] physical properties Control group F Experimental Group E Desizing LOI (%) 0.07 0.06 Warp yarn width (μm) 315 357 <![CDATA[Air permeability (cm 3 / cm 2 / s)]]> 35.2 18.3 Longitudinal impregnation (min) 6.4 5.1 Weft impregnation (min) 2.2 1.0 Warp tensile strength (N / 25mm) 172 206 Weft tensile strength (N / 25mm) 97 143

[0070] According to the data in Table 3, the residual amount of 106 cloth after chemical desizing treatment with the chemical desizing agent for electronic glass fiber cloth in Example 3 is 0.06%, which meets the desizing requirements of 106 cloth. Moreover, compared with conventional thermal desizing treatment, the warp yarn width of 106 cloth after desizing treatment with the chemical desizing agent for electronic glass fiber cloth of the present invention is increased by 13.3%, the air permeability is reduced by 48%, the warp impregnation is 20% faster, the weft impregnation is 55% faster, the warp tensile strength is increased by 20%, and the weft tensile strength is increased by 47%.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A chemical desizing agent for electronic glass fiber cloth, characterized in that: It comprises water and water-soluble oligomers; the water-soluble oligomers consist of a main chain and a side chain, the main chain is a carbon chain with a molecular weight of 300-400, and the side chain contains a hydroxyl group, an amino group and a mercapto group; the mass fraction of the water-soluble oligomers in the electronic glass fiber cloth chemical desizing agent is 30%-50%.

2. The chemical desizing agent for electronic glass fiber cloth according to claim 1, characterized in that: The mass fraction of the water-soluble oligomer in the chemical desizing agent for electronic glass fiber cloth is 35% to 45%.

3. The chemical desizing agent for electronic glass fiber cloth according to claim 1, characterized in that: The main chain in the water-soluble oligomer is a carbon chain with a molecular weight of 305-350.

4. The chemical desizing agent for electronic glass fiber cloth according to claim 1, characterized in that: The mass percentage of hydroxyl groups in the water-soluble oligomer is 0.8% to 1.2%.

5. The chemical desizing agent for electronic glass fiber cloth according to claim 1, characterized in that: The mass percentage of amino groups in the water-soluble oligomer is 6.0% to 7.0%.

6. The chemical desizing agent for electronic glass fiber cloth according to claim 1, characterized in that: The mass percentage of thiol in the water-soluble oligomer is 0.6% to 0.8%.

7. The method for preparing the chemical desizing agent for electronic glass fiber cloth according to any one of claims 1 to 6, characterized in that: The following steps are involved: The water-soluble oligomer is dissolved in water to obtain the chemical desizing agent for electronic glass fiber cloth.

8. Use of the chemical desizing agent for electronic glass fiber cloth according to any one of claims 1 to 6 in a continuous production desizing process.

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