Preparation of silicone raf agent modified adhesive and cast sheet thereof
By modifying the binder with organosilicon RAFT reagent, the problems of flexibility and wettability of traditional PVB binders were solved, and ceramic substrate tapes with low glass transition temperature and high compatibility were achieved, which reduced costs and improved the quality of tapes.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XIAMEN HESSEMIC NEW MATERIAL TECH CO LTD
- Filing Date
- 2023-06-16
- Publication Date
- 2026-07-21
AI Technical Summary
Traditional PVB adhesives have a high glass transition temperature, resulting in poor flexibility of the cast film and poor wettability between ceramic powder and adhesive. This leads to uneven distribution of adhesive on the upper and lower surfaces of the electronic substrate cast film, causing defects such as substrate bending, and also results in high cost.
A method for preparing organosilicon RAFT-modified binders was adopted. Through monomer polymerization and crosslinking reaction, organosilicon RAFT-modified binders with low glass transition temperature were prepared. These binders are used to improve the compatibility between ceramic powder and organic phase, and to enhance the flexibility of cast sheets and the dispersion performance of the binder.
It improves the uniformity of binder distribution in ceramic substrate tapes, lowers the glass transition temperature, enhances the flexibility and compatibility of tapes, reduces costs, avoids the need for additional plasticizers, and improves the migration of tapes and the strength of the sintered ceramic body.
Smart Images
Figure CN116731277B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of adhesive technology, specifically relating to the preparation of an organosilicon RAFT reagent modified adhesive and its casting film. Background Technology
[0002] In recent years, with the rapid development of radio communication, aerospace, and new energy vehicles, electronic ceramic devices are moving towards miniaturization, integration, and multifunctionality. Ceramic casting technology, as a manufacturing technology for electronic components and integrated circuit substrates, has broad development prospects. With the development of electronic technology, the dimensional accuracy requirements for ceramic substrates are becoming increasingly stringent. Traditional electronic substrates generally use PVB (polyvinyl butyral) as a binder. However, electronic substrate castings using PVB as a binder have several problems: ① PVB has a high glass transition temperature, requiring the addition of plasticizers for softening; ② PVB has poor wettability with the ceramic powder in the casting sheet, leading to differences in binder content on the upper and lower surfaces of the electronic substrate casting sheet, resulting in defects such as substrate bending after sintering. Therefore, the design and optimization of the casting slurry system are of great significance for preparing high-quality ceramic substrate castings.
[0003] Silane coupling agents can be used to modify the bonding force between ceramic powder and binder. However, the crosslinked binders produced by this method generally have a high glass transition temperature (Tg), resulting in poor flexibility of the cast sheets. Linear polydimethylsiloxanes can effectively improve the flexibility of cast sheets and enhance the compatibility between the organic phase and alumina powder. However, domestically produced linear polydimethylsiloxane monomers are generally imported and expensive. Therefore, there is an urgent need for a binder with excellent performance that can improve the compatibility between ceramic slurry and organic phase, reduce compatibility with PET, improve the flexibility of cast sheets, and have a low glass transition temperature. Summary of the Invention
[0004] The purpose of this invention is to provide an organosilicon RAFT reagent modified binder and its preparation method, aiming to solve problems such as poor compatibility between alumina powder and organic phase, uneven distribution of binder on the free surface and release surface of cast sheets, and large amount of plasticizer. The binder can reduce compatibility with PET, improve the flexibility of cast sheets, and have a low glass transition temperature.
[0005] The objective of this invention is achieved through the following technical solution: a method for preparing an organosilicon RAFT reagent modified binder, comprising the following steps:
[0006] S1: Monomer polymerization: In a reactor, add 70–90 parts by weight of solvent, 0.01–0.05 parts by weight of initial initiator, 3–18 parts by weight of organosilicon-based RAFT reagent, and dropwise add 10–20 parts by weight of methyl methacrylate, 3–7 parts by weight of hydroxypropyl acrylate, 30–50 parts by weight of butyl acrylate, 10–20 parts by weight of glycidyl methacrylate, and 10–20 parts by weight of hydroxyethyl acrylate. The polymerization reaction is carried out under nitrogen gas at 60–90°C and 200–600 rpm. During the monomer polymerization reaction, continue to dropwise add 0.1–0.5 parts by weight of initiator to the reactor over a period of 4–6 hours. The polymerization reaction time is controlled to be 6–10 hours, yielding a product with a viscosity of 50–70 Pa·s and a weight-average molecular weight of 50,000–100,000 g mol. -1 Linear polymer A;
[0007] S2: Crosslinking: In the above viscous linear polymer A, the temperature is raised to 75-80°C under nitrogen protection with a stirring rate of 100-500 rad / min, and 30-40 parts by weight of isophorone diisocyanate are added for crosslinking reaction for 1-3 hours to obtain the organosilicon RAFT reagent for preparing ceramic casting adhesive.
[0008] Furthermore, the organosilicon-based RAFT reagent has the following structural formula:
[0009]
[0010] R1 represents any one of substituted or unsubstituted methyl or ethyl, substituted or unsubstituted vinyl, or H bond.
[0011] Furthermore, the solvent mentioned in S1 is one or more of toluene, isopropanol, ethyl acetate, butyl acetate, propylene glycol methyl ether, diethylene glycol butyl ether, and dimethyl sulfoxide xylene.
[0012] Furthermore, the initiator mentioned in S1 is one of azobisisobutyronitrile or benzoyl peroxide.
[0013] Furthermore, the structural formula of the linear polymer A described in S1 is as follows:
[0014]
[0015] The sum of a and b in the structural formula is 5-35;
[0016] The number of 'c' values mentioned in the structural formula is 60-85;
[0017] The number of 'd' values in the structural formula is 15-25;
[0018] The number of 'e's in the structural formula is 150-160;
[0019] The number of f's mentioned in the structural formula is 45-60;
[0020] The number of g values shown in the structural formula is 44-75.
[0021] Furthermore, the cross-linking reaction between the isophorone diisocyanate described in S1 and the hydroxyl groups on linear polymer A is as follows:
[0022]
[0023] Where M is a linear polymer A.
[0024] The present invention also provides a cast sheet, comprising the following parts by weight: 200-300 parts alumina powder, 10-20 parts talc powder, 2-3 parts silicon dioxide, 2-8 parts calcium carbonate, 80-120 parts solvent, and 80-120 parts binder. The binder is prepared by the method of preparing the organosilicon RAFT reagent modified binder according to any one of claims 1 to 6. The cast sheet is prepared by the following method: the above components are ball-milled in a ball mill at room temperature and pressure for 20-40 hours to prepare a casting slurry. The casting slurry is heated to 80°C in a casting molding machine to form a cast sheet with a thickness of 200-350 μm.
[0025] The beneficial effects of this invention are:
[0026] 1) The present invention is a silicone RAFT reagent modified binder. After the acrylate binder is modified by the silicone RAFT reagent, a molecular structure containing silicon bond structure is obtained. Due to the good affinity between the silicon bond structure and the ceramic powder, the bonding effect between the acrylate binder and the ceramic powder (mainly silicon dioxide powder) is greatly improved, and the dispersion performance of the binder is improved. It can effectively solve the problem of warping after sintering of electronic ceramic substrate casting film caused by uneven distribution of binder on the free surface and release surface.
[0027] 2) The organosilicon RAFT reagent modified binder of the present invention has good compatibility with alumina powder, and the slurry has a high solid content.
[0028] 3) The silicone RAFT reagent modified binder of the present invention has a low glass transition temperature and can achieve casting without the addition of additional plasticizers.
[0029] 4) The silicone RAFT reagent modified binder of the present invention produces cast sheets with good flexibility, which can ensure good migration of the cast sheets during lamination.
[0030] 5) The organosilicon RAFT reagent modified binder of the present invention has a lower cost than commercially available reactive organosilicon monomers and can be industrialized. Attached Figure Description
[0031] Figure 1 The surface pore morphology of a cast film prepared by using a traditional PVB binder and an organosilicon RAFT reagent-modified binder.
[0032] Figure 2 For linear polymer A 1 HNMR spectrum.
[0033] Figure 3 The image shows the FT-IR spectrum of linear polymer A. Detailed Implementation
[0034] The present invention will be further described in detail below with reference to embodiments. It should also be understood that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. The specific mass, reaction time, temperature, process parameters, etc., in the examples are merely examples within a suitable range. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention.
[0035] Unless otherwise specified, all reagents used are commercially available and were not further purified before use.
[0036] Example 1
[0037] The preparation steps of the silicone RAFT reagent modified binder are as follows:
[0038] S1: Monomer polymerization: 80g toluene, 0.03g initial initiator, 10g silicone-based RAFT reagent, 10g methyl methacrylate, 5g hydroxypropyl acrylate, 45g butyl acrylate, 15g glycidyl methacrylate, and 15g hydroxyethyl acrylate were added to a reactor. The polymerization reaction was carried out under nitrogen gas at 85℃ and 400rpm. During the monomer polymerization, 0.3g initiator was continuously added dropwise to the reactor over a period of 5 hours. The total polymerization time was controlled to 8 hours, yielding a product with a viscosity of 62.35 Pa·s and a weight-average molecular weight of 116861 g mol. -1 Linear polymer A;
[0039] After dehydration and vacuum extraction to remove excess solvent and monomer from linear polymer A, the product was subjected to FT-IR spectroscopy and recorded on a Bruker VERTEX 80V infrared spectrometer, with a spectral range of 400-4000 cm⁻¹. -1 The measurement results are as follows Figure 3 IR spectrum of the sample.
[0040] S2: Crosslinking: In the above viscous linear polymer A, the temperature is raised to 80°C at a stirring rate of 300 rad / min under nitrogen protection, and 38 g of isophorone diisocyanate is added for crosslinking reaction for 2 h to obtain organosilicon RAFT reagent to prepare ceramic casting adhesive.
[0041] exist Figure 3 Middle, 1727cm -1 The absorption peak at 1161 cm⁻¹ is the stretching vibration absorption peak of C=O. -1 The peak at 1450 cm⁻¹ represents the stretching vibration of CO in the ester group co-carbon with the carbonyl group. -1 The peaks at 1020 cm⁻¹ are the symmetric stretching vibration peak of C=O—O— and the C—H stretching vibration absorption peak in S—CH₂—. -1 The absorption peak at 801 cm⁻¹ is the Si-O asymmetric stretching vibration absorption peak in Si-O-CH₃. -1 The absorption peak at 1161 cm⁻¹ is the Si-C stretching vibration peak. -1 The absorption peaks at 2873 and 2958 cm⁻¹ correspond to the C—O—C antisymmetric stretching vibration in ester compounds. -1 The absorption peak at 1388 cm⁻¹ is due to the stretching vibration of C-H in CH₃ and —CH₂—. -1 and 1450cm -1 The peak at 1258 cm⁻¹ represents the bending vibration peak of the C-H groups of methyl and methylene groups. -1 This is the absorption peak of the C—H stretching vibration in Si-CH2, at 907 cm⁻¹. -1 and 842cm -1 The peak at 3515 cm⁻¹ is a characteristic peak of the epoxy group in —CH—O—CH₂—. -1 The absorption peak at position OH represents the stretching vibration of OH, indicating that various monomers such as organosilicon-based RAFT reagent, methyl methacrylate, hydroxypropyl acrylate, butyl acrylate, glycidyl methacrylate, and hydroxyethyl acrylate have been successfully polymerized together.
[0042] After the linear polymer A product is dehydrated and vacuum-extracted to remove excess solvent and monomer, 1 1H NMR spectra were recorded in solution form in CDCl3 using a 600MHz Bruker Avance III spectrometer. The results are as follows: Figure 2 The sample 1 H NMR spectrum, 1 The H NMR spectrum parameters are:
[0043] 1H-NMR (CDCl3, 600MHZ) δ (ppm): 0.06 (d, 9H, -Si-(CH3)3), 0.68 (m, 2H, -Si-CH2-), 1.72 (m, 2H, CH2-CH2-CH2-), 0.32 (t, 2H, -S-CH2-), 1.55 ( m, 2H, -CH-CH2-CH-), 1.54 (m, 1H, -CH2-CH-CH2-), 3.58 (m, 3H, -CO-CH3), 4.09 (m, 1H, -O-CH-CH3), 1.07 (m, 3H, -O-CH-CH3), 4.10 (m, 2H, -CH -CH2-OH), 5.32(m, 2H, -CH2-OH), 3.32(m, 6H, -O-CH2-CH2-CH2-CH3), 0.89(t, 2H, -CH2-CH3), 3.89(m, 2H, -O-CH2-CH-), 3.18(m, 1H, -CH2-C H-O-), 2.56 (m, 2H, -O-CH2-CH-), 1.99 (m, 3H, -CH2-C-CH3), 4.00 (m, 2H, -O-CH2-CH2-), 3.48 (m, 2H, -CH2-CH2-OH), 1.66 (m, 6H, -C-(CH3)2).
[0044] To prepare the cast film, according to the specified ratio, 275g of alumina powder, 11.03g of talc powder, 2.7g of silica, 3.64g of calcium carbonate, 85g of toluene, 28g of isopropanol, 80g of binder, and 400g of a 10mm ball milling tool were added to a ball milling jar. The mixture was ball milled at room temperature and pressure for 24 hours to obtain a cast film slurry. The cast film slurry was then heated to 80℃ in a casting forming machine to form a cast film with a thickness of 200-350μm. The binder was prepared using the method described above.
[0045] The prepared cast films were observed using a scanning electron microscope (SEM). Before analysis, the samples were gold-plated, and the surface morphology was observed using a scanning electron microscope (JSM-7600F, JEOL, Japan). The results are as follows: Figure 1 The SEM scan image shown.
[0046] Following the above method for preparing cast sheets, a traditional PVB binder was used to obtain a PVB binder cast sheet. The same testing method was used to obtain the following results: Figure 1 The SEM scan image shown.
[0047] Figure 1In this context, "free side" refers to the side of the cast sheet facing away from the conveyor belt during the casting process, while "release side" refers to the side of the cast sheet facing the conveyor belt. During the casting process, as the solvent evaporates, the release side of the cast sheet tends to have more adhesive and fewer pores due to similar compatibility, while the free side of the cast sheet has less adhesive and more pores. The free side and release side of the cast sheet exhibit different surface morphology effects during SEM scanning.
[0048] SEM scan results show that the cast film prepared by the modified binder of this invention has fewer pores and smaller pore sizes compared with the cast film prepared by the PVB binder of the prior art. This indicates that the modified binder has better dispersibility in ceramic slurry. The difference in binder content between the upper and lower surfaces of the electronic substrate cast film is small, which helps to reduce defects such as substrate bending after sintering.
[0049] Example 2
[0050] The preparation of the silicone RAFT reagent modified adhesive is based on Example 1, except that the amount of silicone RAFT reagent used in step S1 is 15g and the amount of butyl acrylate is 45g.
[0051] The preparation of the cast film is described in Example 1.
[0052] Example 3
[0053] The preparation of the organosilicon RAFT reagent modified binder is the same as in Example 1, except that the amount of isophorone diisocyanate used in step S2 is 40g.
[0054] The preparation of the cast film is described in Example 1.
[0055] Example 4
[0056] The preparation of the organosilicon RAFT reagent modified binder is described in Example 1.
[0057] The preparation of the cast film is the same as in Example 1, except that the amount of binder used in the cast film is 100g.
[0058] Comparative Example 1
[0059] Adhesive preparation: Take 120g of B76 adhesive, 216g of toluene, and 144g of isopropanol to prepare an adhesive solution.
[0060] Among them, B-76 is Butvar from the United States, and the adhesive model is PVB B-76 polyvinyl butyral.
[0061] The preparation of the cast film is the same as in Example 1, except that the binder used in the cast film is B-76.
[0062] Examples 1-4 and Comparative Example 1: The performance test indicators of the adhesive prepared by the present invention and the existing PVB adhesive are shown in Table 1.
[0063] Table 1. Performance test indicators of the adhesive prepared in this invention and existing PVB adhesives.
[0064] Adhesive weight average molecular weight 116861 81784 127488 116861 105000 Adhesive viscosity / Pa·s 62.35 53.59 63.72 62.35 70.23 Glass transition temperature / °C -10.4 -12.1 -8.3 -10.4 62.0 Viscosity of cast slurry / Pa·s 37.26 35.16 42.19 44.28 46.65 Casting tensile strength / MPa 2.331 1.437 2.514 2.867 4.240 Cast film strain / % 35.20 41.10 36.40 30.90 17.85 Cast film density / g / m3 2.14 2.01 2.14 2.18 1.98
[0065] The weight-average molecular weight of the binder was determined using a Waters GPC instrument. The eluent was tetrahydrofuran, the flow rate was 1.0 mL / min, the temperature was set at 35 °C, and the sample was dissolved in tetrahydrofuran at a concentration of 10 mg / mL.
[0066] The viscosity of the binder and the viscosity of the cast slurry were determined using Anton Paar MCR-102e, at a rotor diameter of 25 mm, an angle of 1°, a temperature of 25°C, and a shear rate of 5 s. -1 The determination was carried out under the specified conditions.
[0067] The glass transition temperature (Tg) of the binder was measured by DSC (Netzsch, Co. Ltd., Bavaria, Germany). The test was conducted by taking 5-10 mg of sample, heating and cooling the sample, and then heating it again, with a temperature change rate of 10 °C / min.
[0068] The tensile strength and strain of the cast film were measured using a universal testing machine (Shimadzu AGS-X-500N, testing range 0-500N), by uniformly cutting the cast film into test strips with a length × width of 30cm × 2cm and measuring at a temperature of 25℃.
[0069] As can be seen from Table 1, the weight-average molecular weight and viscosity of the binder in Examples 1-4 and Comparative Example 1 are similar, indicating that after modification with organosilicon RAFT reagent, the present invention can effectively replace the existing PVB binder during use without causing changes in process parameters, thus facilitating the direct and simple replacement of the existing PVB binder with the modified binder.
[0070] Compared to Comparative Example 1, the modified adhesive of the present invention, as described in Examples 1-4, exhibits a significantly lower glass transition temperature. Therefore, the modified adhesive of the present invention does not require the addition of plasticizers to lower the glass transition temperature during use, which is beneficial for the casting of the modified adhesive slurry. Furthermore, the strain of the cast sheet is also significantly improved. Thus, the cast sheet prepared by the organosilicon RAFT reagent modified adhesive of the present invention has good flexibility, resulting in good migration properties during lamination, ensuring a tighter lamination and improving the strength of the sintered ceramic body.
[0071] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for preparing an organosilicon RAFT-modified adhesive, characterized in that: Includes the following steps, S1: Monomer polymerization: Add the following components by weight to a reactor: 70-90 parts solvent, 0.01-0.05 parts initial initiator, 3-18 parts organosilicon-based RAFT reagent, 10-20 parts methyl methacrylate, 3-7 parts hydroxypropyl acrylate, 30-50 parts butyl acrylate, 10-20 parts glycidyl methacrylate, and 10-20 parts hydroxyethyl acrylate. Polymerize under nitrogen atmosphere at 60-90℃ and 200-600 rpm. During the monomer polymerization, continue to add 0.1-0.5 parts by weight of initiator dropwise to the reactor over 4-6 hours. The polymerization time is controlled to 6-10 hours, yielding a product with a viscosity of 50-70 Pa·s and a weight-average molecular weight of 50,000-100,000 g / mol. -1 Linear polymer A; S2: Crosslinking: In the above viscous linear polymer A, the temperature is raised to 75-80°C under nitrogen protection with a stirring rate of 100-500 rad / min, and 30-40 parts by weight of isophorone diisocyanate are added for crosslinking reaction for 1-3 hours to obtain organosilicon RAFT reagent modified binder.
2. The method for preparing the organosilicon RAFT reagent modified binder according to claim 1, characterized in that: The organosilicon-based RAFT reagent has the following structural formula: R1 represents any one of substituted or unsubstituted methyl or ethyl, substituted or unsubstituted vinyl, or H bond.
3. The method for preparing the organosilicon RAFT reagent modified binder according to claim 1, characterized in that: The linear polymer A has the following structural formula: The sum of a and b in the structural formula is 5-35; The number of 'c' values mentioned in the structural formula is 60-85; The number of 'd' values in the structural formula is 15-25; The number of 'e's in the structural formula is 150-160; The number of f's mentioned in the structural formula is 45-60; The number of g values shown in the structural formula is 44-75.
4. The method for preparing the organosilicon RAFT reagent modified binder according to claim 1, characterized in that: The solvent mentioned in step S1 is one or more of toluene, isopropanol, ethyl acetate, butyl acetate, propylene glycol methyl ether, diethylene glycol butyl ether, dimethyl sulfoxide, and xylene.
5. The method for preparing the organosilicon RAFT reagent modified binder according to claim 1, characterized in that: The initiator mentioned in step S1 is one of azobisisobutyronitrile or benzoyl peroxide.
6. The method for preparing the organosilicon RAFT reagent modified binder according to claim 1, characterized in that: The cross-linking reaction between the isophorone diisocyanate described in S2 and the hydroxyl groups on linear polymer A is as follows: M-OH is a linear polymer A.
7. A cast film, characterized in that: The product is composed of the following parts by weight: 200-300 parts alumina powder, 10-20 parts talc powder, 2-3 parts silica, 2-8 parts calcium carbonate, 80-120 parts solvent, and 80-120 parts binder. The binder is prepared by the method of preparing the organosilicon RAFT reagent modified binder according to any one of claims 1 to 6. The cast sheet is prepared by the following method: the above components are ball-milled in a ball mill at room temperature and pressure for 20-40 hours to prepare a casting slurry. The casting slurry is heated to 80°C in a casting molding machine to form a cast sheet with a thickness of 200-350 μm.