A solvent-free environment-friendly low-viscosity high-performance printing silica gel and a preparation method thereof

Abstract

The application discloses a kind of solvent-free environment-friendly low viscosity high-performance printing silica gel and preparation method thereof, including component A and component B, uniformly mixed, obtain solvent-free environment-friendly low viscosity high-performance printing silica gel, which has lower viscosity, is easy to scrape and silk screen, has excellent construction performance, can realize easy printing, silk screen effect is good, by the use of rheological modifier, different appearance effects such as round corner and right angle can be printed out, and the mechanical property after silk screen is good, has high tensile strength, high elongation, high tear resistance effect, meets the performance requirements of most textile fabrics on the market for printing and coating, and is green and environment-friendly, very friendly to human body and environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of textile printing silicone, in particular to a solvent-free environment-friendly low-viscosity high-performance printing silicone and a preparation method thereof. BACKGROUND

[0002] The printing technology in the textile field has the advantages of scalable production and individual customization, which meets the demand of economic development for improving productivity and the pursuit of individuality. The printing material has evolved from early ink and water-based paste to room temperature vulcanized silicone rubber and now to the widespread use of liquid silicone rubber. Compared with other printing materials, liquid silicone rubber has the advantages of environmental friendliness, excellent colloid mechanics performance, good acid and alkali corrosion resistance, and skin-friendly non-irritating properties, thereby gaining the recognition and favor of many high-end fashion brands.

[0003] The ink used for printing on the market has low viscosity and is easy to print, and the curing conditions are simple and can achieve room temperature curing, so it is widely used in early text and pattern printing of clothing, electronic components, and glassware. However, the solid content of ink is very low, and contains a large amount of organic solvent, which is released during printing, causing harm to the body of the printing operator and polluting the environment. The emergence of paste has alleviated the problem of environmental pollution, but the pattern printed by paste has poor three-dimensional effect and the hand feeling cannot be soft and comfortable. Liquid silicone rubber has the advantages of 100% solid content, soft and comfortable hand feeling after curing, and no release of small molecular products during the curing process, which is friendly to the environment and the human body, and has rapidly risen in the field of clothing printing.

[0004] However, in the face of a wide variety of textile fabrics, especially high-elasticity fabrics, or fabrics that need to be wear-resistant and scratch-resistant, due to the low cohesive energy and high flexibility of silicone rubber molecules, effective interaction cannot be formed within the molecules, resulting in poor mechanical properties of silicone rubber without the addition of reinforcing fillers. Therefore, printing silicone needs to be reinforced accordingly to adapt to the fabric. The current mainstream method is to add silica fillers for reinforcement, and a certain amount of fillers makes the consistency of printing silicone significantly increase, which causes difficulties in printing. In order to facilitate printing, a certain amount of dilution solvent is added during the printing process or the production of printing silicone, and the dilution solvent is released during the thermal curing process of printing silicone, which is harmful to the health of the operator. However, by adding a small amount or even no silica fillers, printing silicone with low viscosity and easy printing can be obtained, but the mechanical properties of the cured silicone are poor, and high strength, high hardness, and high elongation cannot be achieved at the same time, which makes it difficult to deal with high-elasticity fabrics and even causes deformation or rupture.

[0005] Patent CN115785447A discloses a kind of ultra-low viscosity liquid silicone rubber and its crosslinking agent and preparation method, by preparing a low degree of polymerization polysiloxane crosslinking agent, it directly occurs ring-opening copolymerization with cyclotrisiloxane such as trimethyltrivinylcyclotrisiloxane under acidic conditions, realize copolymerization and vulcanization occur simultaneously, and the elastic crosslinking body is prepared, but the product gluing process is complicated, there is certain difficulty in printing process.The patent CN111218116A discloses a kind of low modulus high strength silicone rubber and its preparation method, by selecting the mass of hydrogen in the end containing hydrogen polysilane and oligomeric hydrogen-containing polysilane and the ratio of the two, realize the good comprehensive performance of product, while improving the tensile strength and tear strength, also maintain higher elongation at break, but cannot take into account high hardness, and low hardness will lead to the decline of wear resistance and scratch resistance, cannot meet the demand of high strength wear resistance of fabric.The patent CN106884333A discloses a kind of high-brightness cover printing silicone for screen printing, by using 500-20000cps of vinyl silicone oil, and adding vinyl MQ silicone resin for reinforcement, without using fumed silica that can easily increase the viscosity of matrix to reinforce, so that the silicone rubber matrix can maintain low viscosity, but due to the special three-dimensional network structure of vinyl MQ silicone resin, the hardness of the finally crosslinked and cured matrix is high, and the elongation and tear strength are very low, which cannot realize high performance. SUMMARY

[0006] In view of the problems in the prior art, the purpose of the present application is to provide a kind of solvent-free environmental protection low viscosity high performance printing silicone and its preparation method, its production process is relatively simple, low viscosity and does not contain solvent, without adding diluent, it can realize easy printing, low viscosity can also maintain higher mechanical properties of colloid, can adapt to the different mechanical properties of various fabrics.

[0007] To solve the above problems, the technical scheme adopted by the present application is as follows.

[0008] A kind of solvent-free environmental protection low viscosity high performance printing silicone, component A and component B are 9-11:1;

[0009] A component is composed of the following raw materials by weight:

[0010]

[0011] B component is composed of the following raw materials by weight:

[0012]

[0013]

[0014] In the A component of the present application

[0015] The dual-terminated vinyl polydimethylsiloxane has a viscosity of 500–50000 cps. If the vinyl content in the vinyl silicone oil is too low, the degree of cross-linking of the silicone will decrease, leading to a drop in strength. If the vinyl content is too high, it will exacerbate the embrittlement of the silicone. Appropriate viscosity and vinyl content can control the viscosity within a suitable range to achieve a low-viscosity finished product that is easy to apply. Preferably, the viscosity of the vinyl silicone oil is 3000–20000 cps.

[0016] The single-ended vinyl silicone oil is a polydimethylsiloxane with a vinyl group at one end and a methyl group at the other end, and has a viscosity of 50-5000 cps, preferably 50-500 cps. The single-ended vinyl silicone oil mainly functions to adjust the viscosity and application properties of the printing silicone. Because it contains a single-ended vinyl reactive group, it is less prone to precipitation compared to ordinary dimethyl silicone oil.

[0017] The specific surface area of ​​the reinforcing filler, fumed silica, is 250 m². 2 / g-380m 2 Generally, it is believed that the larger the specific surface area of ​​fumed silica, the higher the transparency of the base adhesive. However, an excessively high specific surface area will cause the viscosity of the base adhesive to increase sharply. A suitable specific surface area and weight fraction can give the base adhesive good transparency while keeping the viscosity within a reasonable range. Preferably, the specific surface area is 250–350 μg. 2 / g. For example, it could be 250m. 2 / g, 280m 2 / g、300m 2 / g, 350m 2 / g etc.

[0018] The polyvinyl silicone oil, in addition to containing vinyl groups at both ends, also contains vinyl groups on its side chains in different directions. During the product's heat curing process, the polyvinyl silicone oil can play a role in "concentrated cross-linking," thereby improving the tear resistance, tensile properties, and other mechanical properties of the printed silicone. Its structural formula is:

[0019]

[0020] Where m>0, n>0, the viscosity is preferably 500-10000, and the vinyl content is preferably 1.5-3.0 wt%.

[0021] The platinum catalyst can be an isopropanol complex of chloroplatinic acid, a di-organic acid ester coordination complex of chloroplatinic acid, a tetrahydrofuran complex of chloroplatinic acid, or a platinum-vinylsiloxane complex, preferably a platinum-vinylsiloxane complex, and its zero-valent platinum content can be 2500 ppm, 3000 ppm, or 5000 ppm.

[0022] The structuring control agent is hexamethyldisilazane, hexamethylcyclotrisilazane, tetramethyldivinyldisilazane, hydroxyl silicone oil, small molecule methoxy silicone oil, small molecule ethoxy silicone oil, dimethyldimethoxysilane, dimethyldiethoxysilane, etc., preferably hexamethyldisilazane.

[0023] According to the present invention, a self-made functional block polysiloxane is provided, mainly used for surface treatment of fumed silica as a reinforcing filler. Its structure is a flexible polysiloxane molecule containing multifunctional groups such as vinyl, ester, and alkoxy groups, with a main chain composed of alkyl and siloxane segments, formed by block copolymerization. The structural formula of the functional block polysiloxane is as follows:

[0024]

[0025] Where m = 4 to 10 and X = 1 to 3, it should be noted that if the value of m is less than 4, the flexibility of the chain segment is insufficient, and if the value of m is greater than 10, the activity of the functional group may be too low, which will ultimately affect the design function and effect. The functional groups R1 and R2 can both be alkyl (methyl or ethyl), or one can be an alkyl (methyl or ethyl) and the other is an alkoxy (methoxy or ethoxy).

[0026] Structural Formula I is primarily used for the surface treatment of silica, a reinforcing filler, in the silicone printing product described in this invention. The terminal alkoxy groups are chemically bonded to the surface of the reinforcing filler, fumed silica, while the vinyl functional groups remain free. During the heat curing process in product use, these free vinyl groups participate in addition reactions with hydrogen-containing groups on the main chain, chemically linking the fumed silica molecules to the polysiloxane main chain of the base adhesive, rather than simply using conventional physical wrapping and winding methods. This chemical linking significantly enhances the mechanical reinforcement effect. The ester groups act as hydrogen bonds between the base adhesive main chain and the fumed silica molecules, while the sufficiently flexible alkyl-siloxane block copolymer chains provide lubrication and toughening effects through the aforementioned chemical and hydrogen bond forces. When the functional block polysiloxane has two or more terminal alkoxy groups, it also positively promotes the adhesion between the finished product and substrates such as textiles. In summary, the use of functional block polysiloxane of structural formula I has a very good positive enhancing effect on the mechanical properties of the finished product, such as tensile strength, tear strength, and adhesive strength.

[0027] In this invention, a self-made tackifier is also provided. In the above structural formula I, when X = 1 to 3, m = 4 to 10, and both R1 and R2 are methoxy groups, or one is methyl and the other is methoxy, it can be used for addition to a specific structure of end-side hydrogen-containing silicone oil, the specific structure of which is as follows:

[0028]

[0029] Where d = 1 to 5, n = 15 to 25, the tackifier required for screen printing silicone rubber of the present invention is obtained by adding structural formula I and the hydrogen-containing silicone oil on the end side. The structural formula of the tackifier is as follows:

[0030]

[0031] In structural formula III, X = 1–3, m = 4–10, n = 15–25, d = 1–5, and both R1 and R2 are methoxy groups, or one is methyl and the other is methoxy.

[0032] Structural Formula III is mainly used as a tackifier in the screen-printed silicone rubber. In actual use, the two or more polyalkoxy groups at the end of Structural Formula II react with polar groups such as hydroxyl groups on the surface of textile fabrics during the heating and curing process, playing a chemical coupling role. The ester groups in the chain segment have a good affinity with most textile fabrics, especially polyester fibers, leather and other substrates. Meanwhile, the polyhydrogen groups at the other end are connected to the main chain of the base rubber through the addition reaction with vinyl groups, thereby achieving the effect of firmly adhering the finished silicone to the textile substrate fabric.

[0033] In component B of the present invention

[0034] The hydrogen-containing silicone oil is a hydrogen-containing polydimethylsiloxane with an active hydrogen content of 0.09 to 0.45 wt%, preferably 0.15 to 0.36 wt%.

[0035] The hydrogen-containing silicone oil with both ends and side chains is a hydrogen-containing polydimethylsiloxane with both ends and side chains. The hydrogen at both ends can play a chain-extending role during the curing process, and the active hydrogen hanging down from the side chains can make the cross-linked network structure after curing more three-dimensional. While improving the hardness and tear resistance of silicone rubber, it can also keep the elongation at break at a high level. Preferably, its active hydrogen content is 0.3 to 0.75 wt%.

[0036] The dimethyl silicone oil is polydimethylsiloxane, with a viscosity of 50-5000 cps. Since polydimethylsiloxane is a non-reactive silicone oil, if the viscosity is too low, migration and precipitation are likely to occur, while if the viscosity is too high, it will affect the construction performance of the finished product. The appropriate weight fraction and viscosity can make the viscosity of the base adhesive within a suitable range. Preferably, the viscosity is 100-500 cps.

[0037] The inhibitor may be one or more of methylbutynol, ethynylcyclohexanol, phenylbutynol, propylbutynol, tetramethyltetravinylcyclotetrasiloxane, cis-bis(2-methoxyethyl)maleate, azobis(2-methoxyethyl)maleate, azobis(N,N-dimethylformamide), etc., preferably ethynylcyclohexanol is selected as the inhibitor.

[0038] The rheology modifier is primarily an epoxy and polyether-modified methyl silicone oil, preferably a bimethyl polysiloxane with epoxy groups and polyether segments in its side chains. More preferably, it has a viscosity of 300–1000 cps and an epoxy value of 0.04–0.08 mol / g. The main function of this rheology modifier is that, when added to a screen-printed liquid silicone rubber system, it can interact with the fumed silica in the screen-printed silicone rubber base through hydrogen bonding, forming a three-dimensional network force-supported structure. This alters the rheological state of the system, transforming it from a self-flowing state to a paste-like thixotropic non-flowing state.

[0039] The self-made thickener is the one described in structural formula III above.

[0040] Beneficial effects of the present invention

[0041] Compared with the prior art, the advantages of this invention are:

[0042] 1. According to the present invention, a self-made functional block polysiloxane is provided, which is mainly used for the surface treatment of reinforcing filler fumed silica. Its structure is a flexible polysiloxane molecule (structural formula I) containing multifunctional groups such as vinyl, ester, and alkoxy groups, and whose main chain is a block copolymer of alkyl and siloxane segments.

[0043] This functional block polysiloxane, as a surface modifier for fumed silica, has at least one methoxy group on its end group, which can chemically couple with the hydroxyl groups on fumed silica to form a more stable and higher bond energy covalent bond. At the same time, the vinyl group exposed on the other end can also be added to the main chain of silicone rubber through addition reaction with the crosslinking agent containing active hydrogen polysiloxane, becoming part of the crosslinking network structure of silicone rubber.

[0044] It is generally believed that when silicone rubber matrix and fumed silica are uniformly mixed, the silicone rubber matrix molecular chains adsorb onto the surface of silica particles, forming stable hydrogen bonds and van der Waals forces, thus acting as physical cross-linking points. When external forces stretch or compress the matrix, the resistance to matrix expansion increases, and the power consumption generated by deformation also increases, thereby enhancing the mechanical properties of the silicone rubber matrix material. However, both hydrogen bonds and van der Waals forces are merely intermolecular forces. Furthermore, covalent bonding cannot be achieved between fumed silica and the silicone rubber matrix; the enhancement effect requires a sufficient amount of filler, leading to a sharp increase in the viscosity of the silicone rubber matrix.

[0045] The self-made functional block polysiloxane of this invention enables coupling between the reinforcing filler fumed silica and the crosslinked network of silicone rubber. By adjusting the degree of polymerization of alkyl or siloxane segments in the flexible segments of the functional block polysiloxane, the distribution of coupling points is adjusted, providing sufficient slip space between the molecules of the silicone rubber backbone. This results in silicone rubber matrix with superior elasticity and higher elongation at break. Covalent coupling of the reinforcing filler and silicone rubber matrix using the functional block polysiloxane significantly enhances the interaction between the reinforcing filler fumed silica and the silicone rubber matrix. This allows a small amount of fumed silica filler to provide a much greater reinforcement effect than conventional methods relying primarily on van der Waals forces and hydrogen bonds. Consequently, the viscosity of the silicone rubber matrix is ​​maintained at a low level, enabling easy printing even without solvents.

[0046] 2. According to the present invention, a multifunctional polysiloxane tackifier containing ester groups, polyalkoxy groups, and multiple hydrogen-containing groups is provided (structural formula II).

[0047] It is generally believed that the bonding mechanism between textile fabrics and adhesives is mechanical interlocking. The surface of textile fabrics is uneven, and when a coating is applied, adhesives, including silicone rubber, penetrate into the fabric's pores. After curing, the adhesive forms a topological structure similar to tenons or screws, firmly binding the adhesive to the textile fabric without the need for covalent bonds or intermolecular forces. However, because the surfaces of substrates such as leather, nylon, and polyester fibers are often smooth and flat, mechanical interlocking cannot be formed. In these cases, intermolecular forces are needed for adsorption, chemical bonds for coupling, or diffusion through Brownian motion of molecules.

[0048] In practical use, the printed silicone rubber of this invention exhibits a chemical coupling effect when two or more polyalkoxy groups at the end of structural formula II react with polar groups such as hydroxyl groups on the surface of textile fabrics during the heating and curing process. The ester groups in the chain segments possess chemical polarity and exhibit good compatibility and affinity with substrates such as leather natural protein fibers, nylon polyamide fibers, and polyester fibers. Meanwhile, the polyhydrogen groups at the other end connect to the main chain of the silicone rubber base through an addition reaction with vinyl groups. During the heating and curing of the printed silicone rubber, the heating conditions promote the aforementioned chemical bonding reactions and the physical wetting of the silicone rubber base and the various substrates, thereby achieving the effect of firmly adhering the finished silicone rubber to the textile substrate fabric.

[0049] 3. This invention uses polysiloxanes with epoxy groups and polyether segments in their side chains as rheology modifiers. By adjusting the amount of rheology modifier in component B, different rheological properties of printing silicone rubber can be formulated, easily achieving various rounded corners, right angles, and different screen printing thicknesses. Compared with traditional common printing silicone rubber processes, this invention improves production efficiency and reduces manufacturing costs for manufacturers. Detailed Implementation

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0051] Example 1

[0052] I. Preparation of Glue A: This includes the preparation of self-made functional block polysiloxane, the preparation of Glue A semi-finished base material, and the preparation of Glue A itself.

[0053] ① Preparation of functional block polysiloxanes:

[0054] 1500g of a double-ended hydrogen-containing silicone oil with an active hydrogen content of 0.397wt% was added to a reactor under nitrogen protection. The mixture was stirred and heated to 68°C. 1.7g of a platinum-vinylsiloxane complex with a zero-valent platinum content of 3000ppm was then added. Next, 200g of 3-(acryloyloxy)propylmethyldimethoxysilane was added in five batches of 40g each, with stirring time of 20 minutes after each addition. After all five additions and the reaction was complete, the temperature was raised, and the excess double-ended hydrogen-containing silicone oil was distilled off under reduced pressure to obtain intermediate product (i).

[0055] 1118.4 g of tetramethyldivinyldisiloxane was added to a reactor. The temperature was raised to 70°C under nitrogen protection. Then, 1358 g of the above intermediate product (i) was added slowly dropwise over 6 hours. After the addition was complete, the reaction was stirred for 30 minutes. Then, the temperature was raised and the excess vinyl double-headed distillate was removed under reduced pressure to obtain the desired functional block polysiloxane.

[0056] ②Preparation of A-grade semi-finished base material:

[0057] In a kneader, 60 parts of 20,000 cps dual-end vinyl silicone oil, 7 parts of 4,000 cps polyvinyl silicone oil with a vinyl content of 1.8 wt%, 10 parts of 300 cps single-end vinyl silicone oil, and 24 parts of a specific surface area of ​​250 m² were added. 2 / g of fumed silica, 6 parts of hexamethyldisilazane, and 4 parts of the above-mentioned self-made functional block polysiloxane are mixed evenly and kneaded at room temperature for 3 hours. Then, the material is heated to 158°C and kneaded under vacuum for 4 hours to obtain the A-grade semi-finished base material.

[0058] ③Preparation of Glue A:

[0059] Weigh out 86 parts of the above semi-finished base material, 14 parts of double-ended vinyl silicone oil with a viscosity of 3000 cps, and 0.4 parts of platinum catalyst with a zero-valent platinum content of 3000 ppm. Put them into a planetary mixer and stir and disperse them for 30 minutes under a vacuum degree ≤ -0.095 MPa to obtain A glue.

[0060] II. Preparation of Glue B: This includes the preparation of tackifiers and the preparation of Glue B.

[0061] ①Preparation of thickener:

[0062] In a 5000ml four-necked flask equipped with a stirrer, thermometer, cooling tube, and funnel, 1821g of end-side hydrogen-containing silicone oil of structural formula II was added. When d=1 and n=20, its active hydrogen content was 0.23wt%. Under nitrogen protection, the material temperature was heated to 65℃. Then, 1.8g of platinum-vinylsiloxane complex catalyst with a zero-valent platinum content of 3000ppm was added, and 866g of the functional block polysiloxane prepared above was added dropwise over approximately 4-5 hours until complete. After complete addition, stirring was continued for 20 minutes to obtain the desired thickener.

[0063] ②Preparation of Glue B:

[0064] Add 1.6 parts of dimethyl silicone oil with a viscosity of 13000, 1.4 parts of the self-made thickener, 3 parts of double-ended hydrogen-containing silicone oil with an active hydrogen content of 0.23wt%, 4 parts of double-ended and side-chain hydrogen-containing silicone oil with an active hydrogen content of 0.53wt%, and 0.04 parts of ethynylcyclohexanol inhibitor to a mixer and stir for 10 minutes to mix evenly to obtain component B.

[0065] Example 2

[0066] I. Preparation of Glue A: This includes the preparation of self-made functional block polysiloxane, the preparation of Glue A semi-finished base material, and the preparation of Glue A itself.

[0067] ① Preparation of functional block polysiloxanes:

[0068] 1500g of a double-ended hydrogen-containing silicone oil with an active hydrogen content of 0.465wt% was added to a reactor under nitrogen protection. The mixture was stirred and heated to 68°C. 1.03g of a platinum-vinylsiloxane complex with a zero-valent platinum content of 5000ppm was then added. Next, 203.5g of 3-(acryloyloxy)propylmethyldimethoxysilane was added in five batches of 40.7g each, with stirring for 20 minutes after each addition. After all five additions and the reaction was complete, the temperature was raised, and the excess double-ended hydrogen-containing silicone oil was distilled off under reduced pressure to obtain intermediate product (ii).

[0069] 1280.2 g of tetramethyldivinyldisiloxane was added to a reactor. The temperature was raised to 70°C under nitrogen protection. Then, 1388 g of the above intermediate product (ii) was added slowly dropwise over 5 hours. After the addition was complete, the reaction was stirred for another 30 minutes. Then, the temperature was raised and the excess vinyl double-headed distillate was removed under reduced pressure to obtain the desired functional block polysiloxane.

[0070] ②Preparation of A-grade semi-finished base material:

[0071] In a kneader, 60 parts of 15000 cps dual-end vinyl silicone oil, 6.2 parts of 3000 cps polyvinyl silicone oil with a vinyl content of 2.5 wt%, 12.3 parts of 500 cps single-end vinyl silicone oil, and 26 parts of a specific surface area of ​​250 m² were added. 2 / g of fumed silica, 6.5 parts of hexamethyldisilazane, and 3.75 parts of the above-mentioned self-made functional block polysiloxane were mixed evenly and kneaded at room temperature for 3 hours. Then the material was heated to 158°C and kneaded under vacuum for 4 hours to obtain the A-grade semi-finished base material.

[0072] ③Preparation of Glue A:

[0073] Weigh out 85 parts of the above semi-finished base material, 15 parts of double-ended vinyl silicone oil with a viscosity of 5000cps, and 0.23 parts of platinum catalyst with a zero-valent platinum content of 5000ppm. Put them into a planetary mixer and stir and disperse them for 30 minutes under a vacuum degree ≤-0.095MPa to obtain A glue.

[0074] II. Preparation of Glue B: This includes the preparation of tackifiers and the preparation of Glue B.

[0075] ①Preparation of thickener:

[0076] In a 3000ml four-necked flask equipped with a stirrer, thermometer, cooling tube, and funnel, 1708.8g of end-side hydrogen-containing silicone oil of structural formula II was added. When d=2 and n=15, its active hydrogen content was 0.35wt%. Under nitrogen protection, the material temperature was heated to 72℃. Then, 0.45g of platinum-vinylsiloxane complex catalyst with a zero-valent platinum content of 3000ppm was added, and 958.8g of the functional block polysiloxane prepared above was added dropwise over approximately 4-5 hours until complete. After complete addition, stirring was continued for 20 minutes to obtain the desired thickener.

[0077] ②Preparation of Glue B:

[0078] Add 1.8 parts of dimethyl silicone oil with a viscosity of 22000 cps, 1.4 parts of the self-made tackifier, 3.2 parts of double-ended hydrogen-containing silicone oil with an active hydrogen content of 0.18 wt%, 3.6 parts of double-ended and side-chain hydrogen-containing silicone oil with an active hydrogen content of 0.65 wt%, 0.035 parts of ethynylcyclohexanol inhibitor, and 0.5 parts of epoxy and polyether modified polysiloxane with an epoxy value of 0.06 mol / g to a mixer and stir for 10 minutes to mix evenly to obtain component B.

[0079] Example 3

[0080] I. Preparation of Glue A: This includes the preparation of self-made functional block polysiloxane, the preparation of Glue A semi-finished base material, and the preparation of Glue A itself.

[0081] ① Preparation of functional block polysiloxanes:

[0082] 1500g of a double-ended hydrogen-containing silicone oil with an active hydrogen content of 0.562wt% was added to a reactor under nitrogen protection. The mixture was stirred and heated to 68°C. 1.5g of a platinum-vinylsiloxane complex with a zero-valent platinum content of 3000ppm was then added. Next, 209g of 2-(acryloyloxy)ethyldimethylmethoxysilane was added in five batches of 41.8g each, with stirring for 20 minutes after each addition. After all five additions and the reaction was complete, the temperature was raised, and the remaining excess double-ended hydrogen-containing silicone oil was distilled off under reduced pressure to obtain intermediate product (iii).

[0083] 1280.2 g of tetramethyldivinyldisiloxane was added to a reactor. The temperature was raised to 70°C under nitrogen protection. Then, 1158 g of the above intermediate product (iii) was added slowly dropwise over 5-6 hours. After the addition was complete, the reaction was stirred for 30 minutes. Then, the temperature was raised and the excess vinyl double-headed distillate was distilled off under reduced pressure to obtain the desired functional block polysiloxane.

[0084] ②Preparation of A-grade semi-finished base material:

[0085] Add 60 parts of 8000 cps dual-end vinyl silicone oil, 8 parts of 5000 cps polyvinyl silicone oil with a vinyl content of 1.5 wt%, 12 parts of 500 cps single-end vinyl silicone oil, and 25 parts of silicone oil with a specific surface area of ​​300 m² to a kneader. 2 / g of fumed silica, 6.25 parts of hexamethyldisilazane, and 2.8 parts of the above-mentioned self-made functional block polysiloxane were mixed evenly and kneaded at room temperature for 3 hours. Then the material was heated to 158°C and kneaded under vacuum for 4 hours to obtain the A-grade semi-finished base material.

[0086] ③Preparation of Glue A:

[0087] Weigh out 83 parts of the above semi-finished base material, 17 parts of double-ended vinyl silicone oil with a viscosity of 20000cps, and 0.4 parts of platinum catalyst and put them into a planetary mixer. Stir and disperse for 1 hour under a vacuum of ≤-0.095MPa to obtain A glue.

[0088] II. Preparation of Glue B: This includes the preparation of tackifiers and the preparation of Glue B.

[0089] ①Preparation of thickener:

[0090] In a 5000ml four-necked flask equipped with a stirrer, thermometer, cooling tube, and funnel, 1816g of end-side hydrogen-containing silicone oil of structural formula II was added. When d=3 and n=20, its active hydrogen content was 0.32wt%. Under nitrogen protection, the material temperature was heated to 65℃. Then, 0.48g of platinum-vinylsiloxane complex catalyst with a zero-valent platinum content of 3000ppm was added, and 700g of the functional block polysiloxane prepared above was added dropwise over approximately 4-5 hours until complete. After complete addition, stirring was continued for 20 minutes to obtain the desired thickener.

[0091] ②Preparation of Glue B:

[0092] Add 2 parts of dimethyl silicone oil with a viscosity of 30000 cps, 1.2 parts of the self-made thickener, 3.5 parts of double-ended hydrogen-containing silicone oil with an active hydrogen content of 0.25 wt%, 3.2 parts of double-ended and side-chain hydrogen-containing silicone oil with an active hydrogen content of 0.7 wt%, 0.03 parts of ethynylcyclohexanol inhibitor, and 0.5 parts of epoxy and polyether modified polysiloxane with an epoxy value of 0.06 mol / g to a mixer and stir for 10 minutes to mix evenly to obtain component B.

[0093] According to the set weight ratio, the A and B adhesives of the above three embodiments were weighed and mixed evenly to obtain a solvent-free, environmentally friendly, low-viscosity, high-performance printing silicone. The printing silicone was printed on various fabrics for screen printing tests, and mechanical property tests were conducted according to the corresponding standards. The main technical parameters are shown in Table 1.

[0094] Compared to a certain brand of screen printing silicone on the market, its hardness is comparable, but its elongation is too low, its tensile strength and tear resistance are also poor, and its viscosity is much higher, so it cannot achieve the printing effect of switching between rounded and right angles.

[0095]

[0096]

[0097] Table 1 Main technical parameters of each embodiment

[0098] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A solvent-free, environmentally friendly, low viscosity, high performance printing silicone, characterized in that: Component A and Component B in a weight ratio of 9-11:1; The A component is composed of the following raw materials by weight: Double-ended vinyl silicone oil 50-65 parts Single-ended vinyl silicone oil 5-10 parts Multi-vinyl silicone oil 5-10 parts Fumed silica 18-24 parts Functional block polysiloxane 2-4 parts Structure control agent 3-6 parts Platinum catalyst 0.2-0.6 parts; The B component is composed of the following raw materials by weight: Dimethyl silicone oil 1-3 parts Double-ended hydrogen-containing silicone oil 3-5 parts Double-ended and side-chain hydrogen-containing silicone oil 3-5 parts Inhibitor 0.01-0.1 parts Rheology modifier 0-1 parts Tackifier 1-4 parts; The multi-vinyl silicone oil contains vinyl groups not only in its double ends but also in its side chains; The structure formula of the functional block polysiloxane is as follows: (structure formula I) In the above structure formula I, when X=1-3, m=4-10, and R1 and R2 are both methoxy or one is methyl and the other is methoxy; the functional block polysiloxane is also used to add to a specific structure of end-side hydrogen-containing silicone oil to prepare a tackifier; the specific structure of the end-side hydrogen-containing silicone oil is as follows: (structure formula II) Wherein, d=1-5, n=15-25, the structure formula I and the specific structure of the end-side hydrogen-containing silicone oil after addition obtain a tackifier required for silk screen silicone rubber, and the structure formula of the tackifier is as follows: (structure III) In the structure formula III, X=1-3, m=4-10, n=15-25, d=1-5, and R1 and R2 are both methoxy or one is methyl and the other is methoxy.

2. The solvent-free, environmentally friendly, low-viscosity, high-performance printing silicone rubber according to claim 1, characterized in that: The double-ended vinyl silicone oil is set as double-ended vinyl polydimethylsiloxane, the viscosity is 500-50000 cps, and the vinyl content is 0.06-0.42 wt%.

3. The solvent-free, environmentally friendly, low-viscosity, high-performance printing silicone rubber according to claim 1, characterized in that: The single-ended vinyl silicone oil is set as polydimethylsiloxane with one end vinyl and the other end methyl, and the viscosity is 50-5000 cps.

4. The solvent-free, environmentally friendly, low-viscosity, high-performance printing silicone rubber and its preparation method according to claim 1, characterized in that: The specific surface area of the fumed silica is 250 m 2 / g-380 m 2 / g.

5. The solvent-free, environmentally friendly, low-viscosity, high-performance printing silicone rubber according to claim 1, characterized in that: The multi-vinyl silicone oil contains vinyl groups not only in its double ends but also in its side chains, which are in different directions, and in the product heating and curing process, the multi-vinyl silicone oil can play a role of "concentrated crosslinking", so that the tear resistance and tensile properties of the printing silicone rubber can be improved, and the structure formula is as follows: Wherein m>0, n>0, the viscosity is 500-10000, and the vinyl content is 1.5-3.0 wt%.

6. A method for preparing the solvent-free, environmentally friendly, low-viscosity, high-performance printing silicone as described in any one of claims 1-5, characterized in that, Including the following preparation steps: Preparation of A glue: including preparation of functional block polysiloxane, preparation of A glue semi-finished base material, and preparation of A glue: ①Preparation of functional block polysiloxane: In the reaction kettle, put in active hydrogen double-end hydrogen-containing silicone oil, nitrogen protection, open the stirring to heat the material temperature, add platinum-vinylsiloxane complex, then add 3-(acryloyloxy) propyl methyl dimethoxysilane to the reaction kettle in batches, a total of 5 times, after each step, stir, after 5 times, the material temperature is raised, the remaining excess double-end hydrogen-containing silicone oil is distilled under reduced pressure, to obtain the intermediate (i); In the reaction kettle, put in tetramethyl divinyl disiloxane, nitrogen protection, raise the material temperature, then add the above intermediate (i) in a slow dropwise manner, after dropwise addition, continue to stir and react, then raise the material temperature, and the excess tetramethyl divinyl disiloxane double seal head is distilled under reduced pressure, to obtain the desired functional block polysiloxane; ②Preparation of A glue semi-finished base material: In the kneader, put in double-end vinyl silicone oil, multi-vinyl silicone oil, single-end vinyl silicone oil, fumed silica, structure control agent hexamethyl disilazane, and the above functional block polysiloxane, stir uniformly, then knead at room temperature, then raise the material temperature, and knead under vacuum and reduced pressure, to obtain the A glue semi-finished base material; ③Preparation of A glue: Put the above semi-finished base material, double-end vinyl silicone oil, and platinum catalyst into the planetary mixer, stir and disperse under a vacuum degree of ≤-0.095 MPa, to obtain the main glue A; Preparation of B glue: including preparation of tackifier and preparation of B glue; ①Preparation of tackifier: In a four-necked flask equipped with a stirrer, thermometer, cooling tube, and funnel, put in the end-side hydrogen-containing silicone oil of structural formula II, heat the material temperature under nitrogen protection, then add platinum-vinylsiloxane complex catalyst, and add the above functional block polysiloxane in a dropwise manner, continue to stir after dropwise addition, to obtain the desired tackifier; ②Preparation of B glue: Take the above tackifier, and take dimethyl silicone oil, double-end hydrogen-containing silicone oil, double-end and side-chain hydrogen-containing silicone oil, and acetylene cyclohexanol inhibitor, mix uniformly to obtain component B; According to the set weight ratio, mix the above A glue and B glue uniformly, to obtain a solvent-free, environmentally friendly, low-viscosity, and high-performance printing silicone glue.

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