One-component dealcoholized sealant and preparation method and application thereof

Abstract

The application discloses a single-component dealcoholized sealant and a preparation method and application thereof. The single-component dealcoholized sealant comprises the following raw materials in parts by mass: 80-120 parts of alkoxyl-terminated polydimethylsiloxane; 40-70 parts of surface-modified silica powder; 10-40 parts of flame retardant; 3-12 parts of flame retardant synergist; 3-12 parts of fumed silica; 5-40 parts of plasticizer; 0.5-10 parts of crosslinking agent; 0.5-10 parts of catalyst; and 0.5-10 parts of adhesion promoter. The structural formula of the alkoxyl-terminated polydimethylsiloxane is shown as formula (I): (R1O)3SiCH2CH2[(CH3)2SiO]nSi(CH3)2CH2Si(OR2)3 n Formula (I), wherein R1 and R2 are independently selected from C1-C10 alkyl, and n is 800-2200. The sealant has good storage stability, low hardness and high elongation, low viscosity, good extrudability, no corrosion to PC, fast curing speed, low density and good flame retardancy.

Description

Technical Field

[0001] This invention belongs to the field of adhesives, and particularly relates to a one-component alcohol-free sealant, its preparation method, and its application. Background Technology

[0002] With the development of technology, the power of mobile phone fast chargers is getting higher and higher, and the charging time of mobile phones is significantly shortened. At present, chargers with 65W and above have become the mainstream on the market, and even fast chargers with 200W and above have been launched on the market. In order to solve the problems of heat dissipation and safety and reliability of fast chargers, a common method is to use adhesives inside the fast charger to dissipate heat and improve safety and reliability.

[0003] Fast chargers typically use two-component silicone addition-cure potting compounds. These compounds have low shrinkage, no byproducts, and good thermal conductivity and insulation properties. However, addition-cure potting compounds have poor adhesion to various substrates, and in the presence of elements such as nitrogen, phosphorus, and sulfur, they can become poisoned, leading to localized incomplete curing. Furthermore, the potting compound is applied throughout the fast charger, significantly increasing its weight and limiting its use. Polycarbonate (PC) is a common plastic widely used in chargers, but corrosion has been a persistent problem in the charger industry.

[0004] The fixing adhesive is applied by dispensing it onto key areas, optimizing the charger design to meet heat dissipation requirements. Furthermore, compared to potting compound, using fixing adhesive adds less weight to the fast charger. The single-component de-alcoholized sealant exhibits excellent adhesion to various metallic and non-metallic materials, is neutral, and non-corrosive; it also demonstrates resistance to tension, vibration, and impact over a wide temperature range, such as -60 to 180°C; and possesses excellent weather resistance, heat resistance, cold resistance, and hydrophobicity, effectively protecting the various components within the charger.

[0005] Common single-component de-alcoholized sealants used as fixing adhesives have the following problems: 1. The product has a short shelf life, and the curing speed decreases significantly with longer storage time, which cannot meet the efficiency requirements of automated production of fast chargers; 2. The hardness is high and the elongation is low, resulting in greater stress in actual applications; 3. The density is too high, which cannot meet the lightweight requirements of fast chargers. Summary of the Invention

[0006] In order to overcome the problems existing in the prior art, one of the objectives of the present invention is to provide a one-component de-alcoholized sealant, which has good storage stability, low hardness and high elongation, low viscosity, good extrudability, does not corrode PC, has fast curing speed, low density, and good flame retardancy.

[0007] The second objective of this invention is to provide a method for preparing the above-mentioned single-component alcohol-free sealant.

[0008] A third objective of this invention is to provide an application of the above-mentioned single-component de-alcoholized sealant in a charger.

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

[0010] A first aspect of the present invention provides a one-component alcohol-based sealant comprising the following raw materials in parts by weight:

[0011]

[0012] The structural formula of the alkoxy-terminated polydimethylsiloxane is shown in formula (I):

[0013] (R1O)3SiCH2CH2[(CH3)2SiO] n Si(CH3)2CH2CH2Si(OR2)3 formula (I);

[0014] In formula (I), R1 and R2 are independently selected from C1 to C10 alkyl groups; n is 800 to 2200;

[0015] The adhesion promoter comprises the following raw materials: aminosilane and epoxysilane;

[0016] The flame retardant includes at least one of phosphate ester, basic zinc carbonate, or nitrogen-phosphorus flame retardant.

[0017] Preferably, in formula (I), R1 and R2 are each independently selected from C1 to C8 alkyl groups; more preferably, in formula (I), R1 and R2 are each independently selected from C1 to C5 alkyl groups; even more preferably, in formula (I), R1 and R2 are each independently selected from methyl, ethyl, or propyl groups.

[0018] Preferably, in formula (I), n is 900 to 2100; more preferably, in formula (I), n is 1000 to 2000; even more preferably, in formula (I), n is 1200 to 1800.

[0019] Preferably, in the one-component de-alcoholized sealant, the alkoxy-terminated polydimethylsiloxane comprises the following raw materials:

[0020] CH2=CH[(CH3)2SiO] m Si(CH3)2CH=CH2 Formula (II);

[0021] HSi(OR3)3 Equation (III);

[0022] In the above formula (II), m is 800 to 2200;

[0023] In formula (III), R3 is a C1 to C10 alkyl group.

[0024] Preferably, in formula (II), m is 900 to 2100; more preferably, in formula (II), m is 1000 to 2000; even more preferably, in formula (II), m is 1200 to 1800.

[0025] Preferably, in formula (III), R3 is a C1 to C8 alkyl group; more preferably, in formula (III), R3 is a C1 to C5 alkyl group; even more preferably, in formula (III), R3 is methyl, ethyl, or propyl.

[0026] Preferably, in the single-component dealcoholized sealant, the alkoxy-terminated polydimethylsiloxane is prepared under the catalysis of a platinum catalyst; more preferably, the platinum catalyst includes at least one of platinum-vinylsiloxane complex, alcohol-modified chloroplatinic acid, and platinum-alkynyl complex; even more preferably, the platinum catalyst is selected from platinum-vinylsiloxane complex.

[0027] Preferably, the alkoxy-terminated polydimethylsiloxane is prepared by the following method, comprising the following steps: CH2=CH[(CH3)2SiO] m Si(CH3)2CH=CH2 and HSi(OR3)3 are mixed under the catalysis of a platinum catalyst to obtain the alkoxy-terminated polydimethylsiloxane.

[0028] Preferably, in the method for preparing the alkoxy-terminated polydimethylsiloxane, the mixing temperature is a first mixing temperature of 50–90°C; more preferably, in the method for preparing the alkoxy-terminated polydimethylsiloxane, the first mixing temperature is 55–85°C; and even more preferably, in the method for preparing the alkoxy-terminated polydimethylsiloxane, the first mixing temperature is 60–80°C.

[0029] Preferably, in the method for preparing the alkoxy-terminated polydimethylsiloxane, the mixing time is a first mixing time, which is 20-100 min; more preferably, in the method for preparing the alkoxy-terminated polydimethylsiloxane, the first mixing time is 25-95 min; even more preferably, in the method for preparing the alkoxy-terminated polydimethylsiloxane, the first mixing time is 30-90 min.

[0030] Preferably, the kinematic viscosity of the alkoxy-terminated polydimethylsiloxane at 25°C is 10–100 Pa·s; more preferably, the kinematic viscosity of the alkoxy-terminated polydimethylsiloxane at 25°C is 15–90 Pa·s; and even more preferably, the kinematic viscosity of the alkoxy-terminated polydimethylsiloxane at 25°C is 20–80 Pa·s.

[0031] Preferably, in the single-component de-alcoholized sealant, the adhesion promoter includes the following raw materials: aminosilane and epoxysilane.

[0032] Preferably, in the raw materials for preparing the adhesion promoter, the molar ratio of the epoxy group of the epoxy silane to the hydrogen on the amino group of the amino silane is (1-5):1; more preferably, in the raw materials for preparing the adhesion promoter, the molar ratio of the epoxy group of the epoxy silane to the hydrogen on the amino group of the amino silane is (1.2-4):1; even more preferably, in the raw materials for preparing the adhesion promoter, the molar ratio of the epoxy group of the epoxy silane to the hydrogen on the amino group of the amino silane is (1.4-3):1.

[0033] Preferably, the adhesion promoter is prepared by the following method, including the following steps: mixing aminosilane and epoxysilane to obtain the adhesion promoter.

[0034] Preferably, in the method for preparing the adhesion promoter, the mixing method involves adding aminosilane dropwise to epoxysilane for mixing.

[0035] Preferably, in the method for preparing the adhesion promoter, the mixing is carried out in an inert gas atmosphere; more preferably, the inert gas includes at least one of nitrogen, argon or helium; even more preferably, the inert gas is selected from nitrogen.

[0036] Preferably, in the method for preparing the adhesion promoter, the mixing temperature is a second mixing temperature of 60–100°C; more preferably, in the method for preparing the adhesion promoter, the second mixing temperature is 65–95°C; and even more preferably, in the method for preparing the adhesion promoter, the second mixing temperature is 70–90°C.

[0037] Preferably, in the method for preparing the adhesion promoter, the mixing time is a second mixing time, which is 3 to 9 hours; more preferably, in the method for preparing the adhesion promoter, the second mixing time is 3.5 to 8.5 hours; even more preferably, in the method for preparing the adhesion promoter, the second mixing time is 4 to 8 hours.

[0038] Preferably, in the one-component de-alcoholized sealant, the flame retardant includes at least one of phosphate ester, basic zinc carbonate, or nitrogen-phosphorus flame retardant; more preferably, in the one-component de-alcoholized sealant, the flame retardant includes at least one of phosphate ester or basic zinc carbonate; even more preferably, in the one-component de-alcoholized sealant, the flame retardant is selected from phosphate ester.

[0039] Preferably, in the single-component alcohol-free sealant, the surface-modified silica powder is prepared by reacting a first surface modifier with silica powder, wherein the first surface modifier includes at least one of methyltrimethoxysilane, vinyltrimethoxysilane, or dodecyltrimethoxysilane; more preferably, in the surface-modified silica powder, the first surface modifier includes at least one of vinyltrimethoxysilane or dodecyltrimethoxysilane.

[0040] Preferably, in the surface-modified silicon micro powder, the mass ratio of silicon micro powder to the first surface modifier is 100:(1-10); more preferably, in the surface-modified silicon micro powder, the mass ratio of silicon micro powder to the first surface modifier is 100:(1.5-5); even more preferably, in the surface-modified silicon micro powder, the mass ratio of silicon micro powder to the first surface modifier is 100:(2-4).

[0041] Preferably, the surface-modified silicon micropowder is modified using a dry processing method.

[0042] Preferably, the surface-modified silicon micropowder is crystalline silicon micropowder, molten silicon micropowder, or a combination thereof.

[0043] Preferably, in the one-component de-alcoholized sealant, the D50 particle size of the surface-modified silica powder is 0.3–12 micrometers; more preferably, in the one-component de-alcoholized sealant, the D50 particle size of the surface-modified silica powder is 0.5–10 micrometers; even more preferably, in the one-component de-alcoholized sealant, the D50 particle size of the surface-modified silica powder is 0.8–8 micrometers.

[0044] Preferably, in the single-component de-alcoholized sealant, the fumed silica is surface-modified fumed silica, which is prepared by reacting a second surface modifier with fumed silica.

[0045] Preferably, in the surface-modified fumed silica, the second surface modifier includes at least one of dimethyldichlorosilane, hexamethyldisilazane, or polysiloxane; more preferably, in the surface-modified fumed silica, the second surface modifier includes at least one of dimethyldichlorosilane or hexamethyldisilazane; even more preferably, in the surface-modified fumed silica, the second surface modifier is selected from dimethyldichlorosilane.

[0046] Preferably, in the surface-modified fumed silica, the mass ratio of fumed silica to the second surface modifier is 100:(1-5); more preferably, in the surface-modified fumed silica, the mass ratio of fumed silica to the second surface modifier is 100:(1.5-4.5); even more preferably, in the surface-modified fumed silica, the mass ratio of fumed silica to the second surface modifier is 100:(2-4).

[0047] Preferably, in the single-component de-alcoholized sealant, the specific surface area of ​​the fumed silica is 80–220 m² / g. 2 / g; More preferably, in the single-component de-alcoholized sealant, the specific surface area of ​​the fumed silica is 100-200 m² / g. 2 / g; More preferably, in the single-component de-alcoholized sealant, the specific surface area of ​​fumed silica is 150-200 m² / g. 2 / g.

[0048] Preferably, in the one-component de-alcoholized sealant, the plasticizer includes at least one of methyl silicone oil, white oil, or alkoxy silicone oil; more preferably, in the one-component de-alcoholized sealant, the plasticizer includes at least one of methyl silicone oil or white oil; even more preferably, in the one-component de-alcoholized sealant, the plasticizer is selected from methyl silicone oil.

[0049] Preferably, in the one-component de-alcoholized sealant, the kinematic viscosity of the plasticizer at 25°C is 80–1200 mPa·s; more preferably, in the one-component de-alcoholized sealant, the kinematic viscosity of the plasticizer at 25°C is 100–1000 mPa·s; even more preferably, in the one-component de-alcoholized sealant, the kinematic viscosity of the plasticizer at 25°C is 100–500 mPa·s.

[0050] Preferably, in the one-component alcohol-based sealant, the flame retardant synergist includes at least one of a silicon-containing compound, a titanium-containing compound, or a rare earth compound; more preferably, in the one-component alcohol-based sealant, the flame retardant synergist includes at least one of magnesium trisilicate, titanium dioxide, or cerium dioxide; even more preferably, in the one-component alcohol-based sealant, the flame retardant synergist includes at least one of magnesium trisilicate or titanium dioxide.

[0051] Preferably, in the one-component alcohol-free sealant, the crosslinking agent includes at least one of methyltrimethoxysilane, ethyltrimethoxysilane, vinyltrimethoxysilane, polymethyltrimethoxysilane, or polyethyltrimethoxysilane; more preferably, in the one-component alcohol-free sealant, the crosslinking agent includes at least one of methyltrimethoxysilane, ethyltrimethoxysilane, vinyltrimethoxysilane, or polymethyltrimethoxysilane; even more preferably, in the one-component alcohol-free sealant, the crosslinking agent includes at least one of methyltrimethoxysilane, ethyltrimethoxysilane, or vinyltrimethoxysilane.

[0052] Preferably, in the one-component dealcoholized sealant, the catalyst includes at least one of the following: ethyl acetoacetate chelate of isopropyl titanate, acetylacetone chelate of isopropyl titanate, ethyl acetoacetate chelate of tert-butyl titanate, or acetylacetone chelate of tert-butyl titanate; more preferably, in the one-component dealcoholized sealant, the catalyst includes at least one of the following: ethyl acetoacetate chelate of isopropyl titanate, acetylacetone chelate of isopropyl titanate, or ethyl acetoacetate chelate of tert-butyl titanate; even more preferably, in the one-component dealcoholized sealant, the catalyst includes at least one of the following: ethyl acetoacetate chelate of isopropyl titanate or acetylacetone chelate of isopropyl titanate.

[0053] Preferably, in the one-component de-alcoholized sealant, the alkoxy-terminated polydimethylsiloxane has a mass fraction of 85-115 parts; more preferably, in the one-component de-alcoholized sealant, the alkoxy-terminated polydimethylsiloxane has a mass fraction of 90-110 parts; and even more preferably, in the one-component de-alcoholized sealant, the alkoxy-terminated polydimethylsiloxane has a mass fraction of 95-105 parts.

[0054] Preferably, the surface-modified silica powder in the one-component de-alcoholized sealant is 42-65 parts by weight; more preferably, the surface-modified silica powder in the one-component de-alcoholized sealant is 45-60 parts by weight; and even more preferably, the surface-modified silica powder in the one-component de-alcoholized sealant is 45-58 parts by weight.

[0055] Preferably, the flame retardant in the one-component de-alcoholized sealant is 15-35 parts by weight; more preferably, the flame retardant in the one-component de-alcoholized sealant is 20-30 parts by weight; and even more preferably, the flame retardant in the one-component de-alcoholized sealant is 22-30 parts by weight.

[0056] Preferably, the flame retardant synergist in the one-component de-alcoholized sealant is 4 to 11 parts by mass; more preferably, the flame retardant synergist in the one-component de-alcoholized sealant is 5 to 10 parts by mass; and even more preferably, the flame retardant synergist in the one-component de-alcoholized sealant is 6 to 9 parts by mass.

[0057] Preferably, the fumed silica in the one-component de-alcoholized sealant is 4 to 11 parts by weight; more preferably, the fumed silica in the one-component de-alcoholized sealant is 5 to 10 parts by weight; and even more preferably, the fumed silica in the one-component de-alcoholized sealant is 6 to 9 parts by weight.

[0058] Preferably, the plasticizer in the one-component de-alcoholized sealant is 8 to 35 parts by weight; more preferably, the plasticizer in the one-component de-alcoholized sealant is 10 to 30 parts by weight; and even more preferably, the plasticizer in the one-component de-alcoholized sealant is 15 to 25 parts by weight.

[0059] Preferably, the crosslinking agent in the one-component de-alcoholized sealant is 0.8 to 8 parts by mass; more preferably, the crosslinking agent in the one-component de-alcoholized sealant is 1 to 5 parts by mass; and even more preferably, the crosslinking agent in the one-component de-alcoholized sealant is 1.5 to 3 parts by mass.

[0060] Preferably, the catalyst in the one-component de-alcoholized sealant is 0.8 to 8 parts by mass; more preferably, the catalyst in the one-component de-alcoholized sealant is 1 to 5 parts by mass; and even more preferably, the catalyst in the one-component de-alcoholized sealant is 1.5 to 3 parts by mass.

[0061] Preferably, the adhesion promoter in the one-component de-alcoholized sealant is 0.8 to 8 parts by weight; more preferably, the adhesion promoter in the one-component de-alcoholized sealant is 1 to 5 parts by weight; and even more preferably, the adhesion promoter in the one-component de-alcoholized sealant is 1.5 to 3 parts by weight.

[0062] Preferably, the one-component alcohol-based sealant comprises the following raw materials in parts by weight:

[0063]

[0064]

[0065] More preferably, the one-component alcohol-based sealant comprises the following raw materials in parts by weight:

[0066]

[0067] More preferably, the one-component alcohol-based sealant comprises the following raw materials in parts by weight:

[0068]

[0069] The second aspect of the present invention provides a method for preparing the single-component de-alcoholized sealant described in the first aspect of the present invention, comprising the following steps: mixing alkoxy-terminated polydimethylsiloxane, surface-modified silica powder, and flame retardant; then adding a plasticizer and mixing; then adding a flame retardant synergist and fumed silica and mixing; and finally adding a crosslinking agent, a catalyst, and an adhesion promoter and mixing to obtain the single-component de-alcoholized sealant.

[0070] Preferably, in the method for preparing the one-component de-alcoholized sealant, the mixing temperature of the alkoxy-terminated polydimethylsiloxane, the surface-modified silica powder, and the flame retardant is a third mixing temperature, which is 100–170°C; more preferably, in the method for preparing the one-component de-alcoholized sealant, the third mixing temperature is 110–160°C; and even more preferably, in the method for preparing the one-component de-alcoholized sealant, the third mixing temperature is 120–150°C.

[0071] Preferably, in the method for preparing the one-component de-alcoholized sealant, the vacuum degree at which the alkoxy-terminated polydimethylsiloxane, surface-modified silica powder, and flame retardant are mixed is the first mixing vacuum degree, which is 0.075–0.100 MPa; more preferably, in the method for preparing the one-component de-alcoholized sealant, the first mixing vacuum degree is 0.080–0.100 MPa; even more preferably, in the method for preparing the one-component de-alcoholized sealant, the first mixing vacuum degree is 0.085–0.095 MPa.

[0072] Preferably, in the method for preparing the one-component de-alcoholized sealant, the mixing time of the alkoxy-terminated polydimethylsiloxane, the surface-modified silica powder, and the flame retardant is the third mixing time, which is 100-200 min; more preferably, in the method for preparing the one-component de-alcoholized sealant, the third mixing time is 110-190 min; and even more preferably, in the method for preparing the one-component de-alcoholized sealant, the third mixing time is 120-180 min.

[0073] Preferably, in the method for preparing the one-component de-alcoholized sealant, the temperature at which the plasticizer is added and mixed is a fourth mixing temperature, which is 100–170°C; more preferably, in the method for preparing the one-component de-alcoholized sealant, the fourth mixing temperature is 110–160°C; and even more preferably, in the method for preparing the one-component de-alcoholized sealant, the fourth mixing temperature is 120–150°C.

[0074] Preferably, in the method for preparing the one-component de-alcoholized sealant, the vacuum degree for mixing with the plasticizer is the second mixing vacuum degree, which is 0.075–0.105 MPa; more preferably, in the method for preparing the one-component de-alcoholized sealant, the second mixing vacuum degree is 0.080–0.100 MPa; even more preferably, in the method for preparing the one-component de-alcoholized sealant, the second mixing vacuum degree is 0.085–0.095 MPa.

[0075] Preferably, in the method for preparing the one-component de-alcoholized sealant, the mixing time for adding the plasticizer is the fourth mixing time, which is 20-100 min; more preferably, in the method for preparing the one-component de-alcoholized sealant, the fourth mixing time is 25-95 min; even more preferably, in the method for preparing the one-component de-alcoholized sealant, the fourth mixing time is 30-90 min.

[0076] Preferably, in the preparation method of the single-component de-alcoholized sealant, the temperature at which the flame retardant synergist and fumed silica are added and mixed is the fifth mixing temperature, which is 20–40°C; more preferably, in the preparation method of the single-component de-alcoholized sealant, the fifth mixing temperature is 22–38°C; and even more preferably, in the preparation method of the single-component de-alcoholized sealant, the fifth mixing temperature is 25–35°C.

[0077] Preferably, in the method for preparing the one-component de-alcoholized sealant, the vacuum degree at which the flame retardant synergist and fumed silica are mixed is the third mixing vacuum degree, which is 0.075–0.105 MPa; more preferably, in the method for preparing the one-component de-alcoholized sealant, the third mixing vacuum degree is 0.080–0.100 MPa; and even more preferably, in the method for preparing the one-component de-alcoholized sealant, the third mixing vacuum degree is 0.085–0.095 MPa.

[0078] Preferably, in the method for preparing the single-component de-alcoholized sealant, the mixing time for adding the flame retardant synergist and fumed silica is the fifth mixing time, which is 10-50 min; more preferably, in the method for preparing the single-component de-alcoholized sealant, the fifth mixing time is 15-45 min; and even more preferably, in the method for preparing the single-component de-alcoholized sealant, the fifth mixing time is 20-40 min.

[0079] Preferably, in the method for preparing the single-component de-alcoholized sealant, the mixing speed of the flame retardant synergist and fumed silica is a first mixing speed of 15-40 Hz; more preferably, in the method for preparing the single-component de-alcoholized sealant, the first mixing speed is 20-35 Hz; even more preferably, in the method for preparing the single-component de-alcoholized sealant, the first mixing speed is 25-30 Hz.

[0080] Preferably, in the method for preparing the one-component de-alcoholized sealant, the temperature at which the crosslinking agent, catalyst, and adhesion promoter are added and mixed is the sixth mixing temperature, which is 20–40°C; more preferably, in the method for preparing the one-component de-alcoholized sealant, the sixth mixing temperature is 22–38°C; and even more preferably, in the method for preparing the one-component de-alcoholized sealant, the sixth mixing temperature is 25–35°C.

[0081] Preferably, in the method for preparing the one-component de-alcoholized sealant, the vacuum degree at which the crosslinking agent, catalyst, and adhesion promoter are mixed is a fourth mixing vacuum degree, which is 0.075–0.105 MPa; more preferably, in the method for preparing the one-component de-alcoholized sealant, the fourth mixing vacuum degree is 0.080–0.100 MPa; and even more preferably, in the method for preparing the one-component de-alcoholized sealant, the fourth mixing vacuum degree is 0.085–0.095 MPa.

[0082] Preferably, in the method for preparing the one-component de-alcoholized sealant, the mixing time for adding the crosslinking agent, catalyst, and adhesion promoter is the sixth mixing time, which is 10-50 min; more preferably, in the method for preparing the one-component de-alcoholized sealant, the sixth mixing time is 15-45 min; even more preferably, in the method for preparing the one-component de-alcoholized sealant, the sixth mixing time is 20-40 min.

[0083] Preferably, in the method for preparing the one-component de-alcoholized sealant, the mixing speed of the crosslinking agent, catalyst, and adhesion promoter is a second mixing speed of 10-35 Hz; more preferably, in the method for preparing the one-component de-alcoholized sealant, the second mixing speed is 15-30 Hz; and even more preferably, in the method for preparing the one-component de-alcoholized sealant, the second mixing speed is 20-25 Hz.

[0084] The third aspect of the present invention provides the application of the single-component de-alcoholized sealant described in the first aspect of the present invention, or the single-component de-alcoholized sealant prepared by the preparation method described in the second aspect of the present invention, in a charger.

[0085] Preferably, the charger is a fast charger; more preferably, the charger is a fast charger for mobile phones.

[0086] Preferably, the fast charger has a charging power of 65W or higher; more preferably, the fast charger has a charging power of 200W or higher.

[0087] The beneficial effects of this invention are as follows: This invention provides a one-component alcohol-based sealant with a long shelf life, reaching up to 12 months at room temperature, with no significant decrease in curing speed, good storage stability, and low volatile content. Simultaneously, this sealant has low hardness and high elongation, effectively protecting internal components during drop tests on chargers. It has low viscosity, good extrudability, excellent adhesion to PC without corroding it. It cures quickly and has low density, meeting the requirements of streamlined production lines and lightweight products. Furthermore, the product is free of halogens and other harmful substances, complying with EU RoHS and REACH regulations. It also exhibits good flame retardancy, meeting the UL94 V0 standard requirements.

[0088] Specifically, compared with the prior art, the present invention has the following advantages:

[0089] 1. The single-component alcohol-free sealant prepared by the present invention uses the alkoxy-terminated polydimethylsiloxane of the present invention. Compared with the alkoxy-terminated polydimethylsiloxane obtained by condensation reaction of alkoxysilane and 107 glue, it has better storage stability and lower volatile content.

[0090] 2. This invention uses silicon micropowder, combined with flame retardants and flame retardant synergists, which greatly reduces the amount of flame retardant used. The flame retardant content accounts for only 10-15% of the total amount, which is enough to have good flame retardancy. The flame retardant performance meets the UL94 V0 standard requirements. At the same time, due to the reduction in the amount of flame retardant added, the hardness of the product is reduced and the elongation of the product is increased. According to GB / T 13477, the hardness of the product is ≤45 Shore A and the elongation is ≥500%.

[0091] 3. This invention ensures that the flame retardancy reaches UL94 V0 and the plasticizer content is 5-15%, while giving the product low viscosity and good extrudability, making it suitable for automated dispensing during charger production and improving efficiency.

[0092] 4. The adhesion promoter used in this invention makes the resulting sealant product non-corrosive to PC, thus solving the PC corrosion problem that has been difficult to solve in the charger industry.

[0093] 5. The sealant prepared by this invention also has a fast curing speed and low density, which can meet the requirements of automated production lines and product lightweighting. In addition, the product does not contain halogens or other harmful substances and complies with EU RoHS and REACH regulations.

[0094] 6. The preparation method of the sealant provided by the present invention is simple, easy to implement, safe and environmentally friendly, and has high production efficiency, making it suitable for large-scale industrial application. Detailed Implementation

[0095] The following specific embodiments further illustrate the content of the present invention in detail. 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. Non-essential improvements and adjustments made by those skilled in the art based on the principles described in the present invention are all within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make selections within a suitable range based on the description herein, and are not intended to be limited to the specific data in the examples below. Unless otherwise specified, the raw materials, reagents, or apparatus used in the following embodiments and comparative examples can be obtained from conventional commercial sources or by existing known methods. I. Alkoxy-terminated polydimethylsiloxanes

[0096] The structural formula of the alkoxy-terminated polydimethylsiloxane of the present invention is shown in formula (I):

[0097] (R1O)3SiCH2CH2[(CH3)2SiO] n Si(CH3)2CH2CH2Si(OR2)3 formula (I);

[0098] In formula (I), R1 and R2 are independently selected from C1 to C10 alkyl groups; n is 800 to 2200.

[0099] Using the above-mentioned alkoxy-terminated polydimethylsiloxane as the base polymer can improve the storage stability of the sealant. To obtain better reactivity, R1 and R2 are independently selected from methyl or ethyl groups, and n is 1400–1600.

[0100] II. Surface-modified silica powder

[0101] The silicon micropowder of this invention is crystalline or molten silicon micropowder treated with a surface treatment agent, and the treatment is carried out using a dry method. After treatment, the silicon micropowder can improve its compatibility with the base polymer and reduce the viscosity of the sealant.

[0102] III. Flame retardants

[0103] The flame retardant of this invention is one or more of phosphate esters, basic zinc carbonate, and nitrogen-phosphorus flame retardants, without using halogenated flame retardants that do not meet environmental protection requirements or inorganic flame retardants (such as aluminum hydroxide or magnesium hydroxide) with general flame retardant effects. The use of high-efficiency flame retardants reduces the proportion of flame retardants, reduces the density and hardness of the product, and has a relatively small impact on the mechanical properties of the product.

[0104] IV. Flame Retardant Synergists

[0105] This invention adds a flame retardant synergist, which enables the sealant to have superior flame retardant properties. Without the flame retardant synergist, the amount of flame retardant used needs to be increased by 50-100% to achieve the same flame retardant effect. Furthermore, reducing the amount of flame retardant helps to lower the product's hardness and increase its elongation.

[0106] V. Fumed silica

[0107] In this embodiment and comparative example, the fumed silica used is surface-modified fumed silica. Surface-modified fumed silica exhibits better compatibility with the aforementioned alkoxy-terminated polydimethylsiloxane. Furthermore, as a reinforcing filler in the sealant, it improves the tensile strength of the sealant and imparts good thixotropic properties, preventing stringing during dispensing. The fumed silica used in this embodiment and comparative example is Degussa R974.

[0108] VI. Plasticizers

[0109] In this embodiment and comparative example, the plasticizer used is methyl silicone oil, which has a kinematic viscosity of 100 mPa·s at 25°C. Adding methyl silicone oil as a plasticizer can improve the extrusion rate of the sealant and increase the elongation at break of the sealant.

[0110] VII. Crosslinking Agent

[0111] The crosslinking agent described in this invention is at least one of methyltrimethoxysilane, ethyltrimethoxysilane, vinyltrimethoxysilane, polymethyltrimethoxysilane, and polyethyltrimethoxysilane.

[0112] VIII. Catalysts

[0113] The catalyst described in this invention is at least one of the following: ethyl acetoacetate chelate of isopropyl titanate, acetylacetone chelate of isopropyl titanate, ethyl acetoacetate chelate of tert-butyl titanate, and acetylacetone chelate of tert-butyl titanate.

[0114] 9. Adhesion promoters

[0115] The adhesion promoter described in this invention is a reaction product of aminosilane and epoxysilane. The sealant prepared using this reaction product has been experimentally verified to have good adhesion to PC plastic and does not corrode it. However, if aminosilane is directly used as the adhesion promoter, PC plastic will corrode. In this embodiment and comparative example, the aminosilane used is KH550, and the epoxysilane is KH560.

[0116] Example 1

[0117] A one-component alcohol-based sealant comprises the following raw materials in parts by weight:

[0118]

[0119] The structural formula of the alkoxy-terminated polydimethylsiloxane is shown in formula (I):

[0120] (CH3O)3SiCH2CH2[(CH3)2SiO] 1500 Si(CH3)2CH2CH2Si(OCH3)3 formula (I).

[0121] The alkoxy-terminated polydimethylsiloxane shown in formula (I) is prepared by the following method:

[0122] CH2=CH[(CH3)2SiO] 1500 Si(CH3)2CH=CH2 and HSi(OCH3)3 were mixed and reacted at 80°C for 60 min under the catalysis of a caster platinum catalyst to obtain the alkoxy-terminated polydimethylsiloxane, which has a kinematic viscosity of 60 Pa·s at 25°C. The caster platinum catalyst was bis(1,3-divinyl-1,1,3,3-tetramethyldisiloxane)platinum.

[0123] The surface-modified silicon powder 1 is a molten silicon powder obtained by modifying it with vinyltrimethoxysilane using a dry processing method. The mass ratio of silicon powder to vinyltrimethoxysilane is 100:2, and the D50 particle size of the surface-modified silicon powder 1 is 5 micrometers.

[0124] The fumed silica is a surface-modified fumed silica treated with dimethyldichlorosilane. The mass ratio of fumed silica to dimethyldichlorosilane is 100:2, and the specific surface area of ​​the fumed silica is 200 m² / g. 2 / g.

[0125] The adhesion promoter is the reaction product of aminosilane KH550 and epoxysilane KH560, wherein the molar ratio of the epoxy group of the epoxysilane to the hydrogen on the amino group of the aminosilane is 1.5:1. The reaction is carried out in a three-necked flask in a constant temperature water bath at 75°C, and specifically includes the following steps: first, aminosilane is added to the three-necked flask and stirring is started; epoxysilane is added dropwise; after the addition is complete, stirring is continued for 6 hours; the reaction is carried out under nitrogen protection.

[0126] The preparation method of the above-mentioned one-component alcohol-free sealant includes the following steps:

[0127] (1) The above-mentioned alkoxy-terminated polydimethylsiloxane, surface-modified silica powder and flame retardant were added to a planetary mixer with heating function and dehydrated and mixed for 130 minutes at 130°C and vacuum degree 0.093MPa.

[0128] (2) Add plasticizer and circulate cooling water or ice water to lower the material temperature to below 40°C before proceeding to the next step;

[0129] (3) Add flame retardant synergist and fumed silica. Add the silica in several batches. After the silica is completely mixed into the base material, stir for 30 minutes under a vacuum of 0.093 MPa and a speed of 30 Hz.

[0130] (4) Add the crosslinking agent, catalyst and adhesion promoter into a planetary mixer and stir for 30 minutes at a vacuum of 0.093 MPa and a speed of 25 Hz to obtain the single-component alcohol-free sealant.

[0131] Example 2

[0132] A one-component alcohol-based sealant comprises the following raw materials in parts by weight:

[0133]

[0134] The surface-modified silicon powder 2 is a molten silicon powder modified by a dry process using dodecyltrimethoxysilane. The mass ratio of silicon powder to dodecyltrimethoxysilane is 100:4, and the D50 particle size of the surface-modified silicon powder 2 is 8 micrometers.

[0135] The alkoxy-terminated polydimethylsiloxane, titanium dioxide, fumed silica, methyl silicone oil, methyltrimethoxysilane, ethyl acetoacetate chelate of isopropyl titanate, and adhesion promoter in this embodiment are the same as in Example 1.

[0136] The single-component de-alcoholized sealant of this embodiment was prepared according to the preparation method of Example 1.

[0137] Comparative Example 1

[0138] The raw materials and preparation method of the single-component de-alcoholized sealant in this comparative example are basically the same as those in Example 1, except that the surface-modified silica powder in Example 1 is replaced with unmodified ordinary silica powder.

[0139] Comparative Example 2

[0140] The raw materials and preparation method of the single-component de-alcoholized sealant in this comparative example are basically the same as those in Example 1, except that the adhesion promoter in Example 1 is replaced with aminosilane KH550.

[0141] Comparative Example 3

[0142] The raw materials and preparation method of the single-component de-alcoholized sealant in this comparative example are basically the same as those in Example 1, except that the flame retardant in Example 1 is replaced with aluminum hydroxide.

[0143] Comparative Example 4

[0144] The raw materials and preparation method of the single-component de-alcoholized sealant in this comparative example are basically the same as those in Example 1, except that the flame retardant synergist of Example 1 is omitted.

[0145] Comparative Example 5

[0146] The raw materials and preparation method of the single-component alcohol-free sealant in this comparative example are basically the same as those in Example 1, except that the alkoxy-terminated polydimethylsiloxane in Example 1 is replaced with the alkoxy-terminated polydimethylsiloxane obtained by the condensation reaction of alkoxysilane and 107 glue, with the structural formula (CH3O)3SiO[(CH3)2SiO] 1500 Si(OCH3)3.

[0147] The one-component de-alcoholized sealants prepared in Examples 1-2 and Comparative Examples 1-5 were tested for performance according to GB / T 13477, and the results are shown in Table 1.

[0148] Table 1. Performance test results of the one-component alcohol-based sealants in Examples 1-2 and Comparative Examples 1-5

[0149]

[0150]

[0151] The test results above show that the single-component alcohol-based sealant prepared by this invention has a long shelf life, reaching 12 months at room temperature, with no significant decrease in curing speed, good storage stability, and low volatile content. It also exhibits low hardness and high elongation; according to GB / T 13477, the product's hardness is ≤45 Shore A and its elongation is ≥500%, effectively protecting internal components during drop tests on chargers. Furthermore, it has low viscosity, good extrusion performance, good adhesion to PC, and does not corrode PC. It cures quickly and has low density, meeting the requirements of automated production lines and lightweight products. The product is free of halogens and other harmful substances, complying with EU RoHS and REACH regulations. It also has good flame retardancy, meeting the UL94 V0 standard requirements.

[0152] Furthermore, the preparation method of the sealant provided by this invention is simple, easy to implement, safe, environmentally friendly, and highly efficient, making it suitable for large-scale industrial applications. The single-component de-alcoholized sealant obtained by this invention can be used in chargers, and has wide applications in fast chargers, especially mobile phone fast chargers.

Claims

1. A one-component dealcoholized sealant, characterized in that, The raw materials include the following parts by weight: 80-120 parts of alkoxy-terminated polydimethylsiloxane; 40-70 parts of surface-modified silica powder; 10-40 parts flame retardant; 3-12 parts of flame retardant synergist; 3-12 parts of fumed silica; Plasticizer 5-40 parts; Crosslinking agent 0.5~10 parts; Catalyst 0.5~10 parts; Adhesion promoter 0.5~10 parts; The structural formula of the alkoxy-terminated polydimethylsiloxane is shown in formula (I): (R1O)3SiCH2CH2[(CH3)2SiO] n Si(CH3)2CH2CH2Si(OR2)3formula (I); In formula (I), R1 and R2 are both selected from methyl groups; n is 1200~1800; The kinematic viscosity of the alkoxy-terminated polydimethylsiloxane at 25°C is 20~80 Pa·s; The adhesion promoter comprises the following raw materials: aminosilane and epoxysilane; the adhesion promoter is prepared by a method including the following steps: mixing aminosilane and epoxysilane to obtain the adhesion promoter; the mixing is carried out in an inert gas atmosphere; the mixing temperature is a second mixing temperature, which is 60~100℃; the molar ratio of hydrogen on the epoxy group of the epoxysilane to hydrogen on the amino group of the aminosilane is (1~5):1; The flame retardant includes at least one of phosphate ester or basic zinc carbonate; The surface-modified silicon micro powder is prepared by reacting a first surface modifier and silicon micro powder. The first surface modifier includes at least one of methyltrimethoxysilane, vinyltrimethoxysilane, or dodecyltrimethoxysilane. The mass ratio of silicon micro powder to the first surface modifier in the surface-modified silicon micro powder is 100:(2~4). The flame retardant synergist includes at least one of magnesium trisilicate or titanium dioxide. The fumed silica is a surface-modified fumed silica, which is prepared by reacting a second surface modifier with fumed silica; the second surface modifier is selected from dimethyldichlorosilane; in the surface-modified fumed silica, the mass ratio of fumed silica to the second surface modifier is 100:(1~5). The plasticizer includes at least one of methyl silicone oil, white oil, or alkoxy silicone oil; The crosslinking agent includes at least one of methyltrimethoxysilane, ethyltrimethoxysilane, vinyltrimethoxysilane, polymethyltrimethoxysilane, or polyethyltrimethoxysilane; The catalyst comprises at least one of the following: ethyl acetoacetate chelate of isopropyl titanate, acetylacetone chelate of isopropyl titanate, ethyl acetoacetate chelate of tert-butyl titanate, or acetylacetone chelate of tert-butyl titanate.

2. The one-part dealcoholized sealant of claim 1, wherein The alkoxyl terminated polydimethylsiloxane includes the following raw materials of preparation: CH2=CH[(CH3)2SiO] m Si(CH3)2CH=CH2Formula (II); HSi(OR3)3 formula (III); In the formula (II), m is 1200~1800; In formula (III), R3 is a methyl group.

3. The one-component dealcoholized sealant according to claim 1 or 2, wherein The alkoxy-terminated polydimethylsiloxane was prepared under the catalysis of a platinum catalyst.

4. The one-part dealcoholized sealant of claim 1, wherein, The D50 particle size of the surface-modified silicon micropowder is 0.3~12 micrometers.

5. The single-component alcohol-free sealant according to claim 1, characterized in that, The specific surface area of the fumed white carbon is 80-220 m 2 / g.

6. The single-component alcohol-free sealant according to claim 1, characterized in that, The plasticizer has a kinematic viscosity of 80~1200 mPa·s at 25°C.

7. A method for preparing the single-component alcohol-based sealant according to any one of claims 1 to 6, characterized in that, Includes the following steps: Alkoxy-terminated polydimethylsiloxane, surface-modified silica powder, and flame retardant are mixed together, then a plasticizer is added and mixed, followed by the addition of a flame retardant synergist and fumed silica. Finally, a crosslinking agent, a catalyst, and an adhesion promoter are added and mixed to obtain the single-component de-alcoholized sealant.

8. The application of a one-component de-alcoholized sealant in a charger, characterized in that, The single-component alcohol-free sealant is the single-component alcohol-free sealant according to any one of claims 1 to 6, or the single-component alcohol-free sealant prepared by the preparation method according to claim 7.

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