A food-grade silicone anti-slip cushioning bottom glassware and its coating and curing preparation process

Abstract

This invention discloses a food-grade silicone anti-slip cushioning bottom layer for glassware and its coating and curing process. The anti-slip bottom layer is cured from a self-coated food-grade liquid silicone rubber composition, which contains a base liquid silicone rubber and an interface enrichment agent package. The agent package consists of a silane coupling agent and a polar azeotropic carrier solvent containing glacial acetic acid. After degassing, the composition is directly coated onto a clean glass bottom and subjected to step-by-step nonlinear curing. In the first stage, a low-temperature isothermal process is used, where the polar solvent drives the coupling agent to migrate directionally to the glass interface, achieving in-situ bonding catalyzed by glacial acetic acid. In the second stage, a high-temperature isothermal process is used to promote solvent dissipation and bulk cross-linking. This invention eliminates the need for surface physical activation and a base coating process, forming a continuous chemical gradient structure with decreasing coupling agent concentration, eliminating interfacial physical breaks and dispersing thermal stress. It achieves bubble-free in-situ anchoring under thick film conditions, effectively improving the adhesion durability of the bottom layer.

Description

Technical Field

[0001] This invention relates to the field of functional modification technology for daily-use glassware, specifically to a food-grade silicone anti-slip cushioning bottom glassware and its coating and curing preparation process. Background Technology

[0002] Everyday glassware is widely used in households, catering, and baby care due to its stable chemical properties, ease of cleaning, and high transparency. Common everyday glassware includes glass water glasses, food storage jars, and baby water cups, which are everyday containers for holding and storing food.

[0003] In practical use, glass is a smooth and fragile rigid material. To prevent glassware from slipping and tipping over when in contact with tabletops, reduce bumps and noise during movement, and prevent scratches, the industry typically adds a layer of liquid silicone rubber as an anti-slip cushioning layer to the bottom of the glassware. However, due to the low surface energy of glass, liquid silicone rubber is difficult to apply directly and firmly. Existing liquid silicone rubber bottom coating processes usually involve multiple steps: before applying the adhesive, the glass bottom surface is physically activated using a plasma or flame treatment device; then a separate, specialized primer is applied; after air drying to form a transition film, the liquid silicone rubber is applied and cured.

[0004] Existing multi-step coating processes have the following drawbacks: the process flow, which relies on surface physical activation and independent primer drying, is lengthy, increasing equipment investment in the production line; and the turnover between multiple processes reduces mass production efficiency. Furthermore, the anti-slip underlayer formed by stacking multiple layers creates physical interfaces between the glass substrate, the primer layer, and the silicone body. Due to the differences in the coefficients of thermal expansion of the different layers, when glassware is subjected to alternating hot and cold environments such as dishwasher washing or microwave heating, thermal stress concentration easily occurs at these physical interfaces, leading to edge lifting or interlayer peeling of the silicone layer, resulting in poor overall adhesion durability. Summary of the Invention

[0005] The technical problem solved by this invention is that conventional glassware has a smooth bottom, which makes it easy to slip, tip over, bump, and scratch the countertop during use; while existing methods of attaching silicone feet have problems such as easy detachment, water accumulation and dirt trapping in the joints, and failure to meet food-grade contact standards; at the same time, glass has low surface energy, and direct application of liquid silicone has poor adhesion, easy delamination and peeling, and conventional multi-step base coating process is cumbersome, energy-intensive, and the physical coating formed after curing is prone to stress concentration and peeling under alternating hot and cold environments.

[0006] To address the above problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a food-grade silicone anti-slip cushioning bottom glass container, which adopts the following technical solution: A food-grade silicone anti-slip cushioning bottom glassware includes a glassware and an anti-slip cushioning bottom layer disposed on the bottom surface of the glassware. The anti-slip cushioning bottom layer is formed by curing a self-coated food-grade liquid silicone rubber composition. The self-coated food-grade liquid silicone rubber composition contains the following components in parts by weight: 100 parts of base liquid silicone rubber; 0.5 to 2.0 parts of an interface enrichment agent package. The interface enrichment agent package is composed of components containing the following percentages by weight: 66.7% to 80.0% silane coupling agent; and 20.0% to 33.3% polar azeotropic carrier solvent.

[0007] By adopting the above technical solution, an interface enrichment agent package containing a polar azeotropic carrier solvent and a silane coupling agent is used, combined with a base liquid silicone rubber to form a self-priming system. This eliminates the need for separate surface physical activation and separate primer application processes. The polar azeotropic carrier solvent and the non-polar base liquid silicone rubber have polarity and boiling point differences. Under heating conditions, the polar azeotropic carrier solvent diffuses directionally towards the high surface energy glass interface, simultaneously carrying the silane coupling agent to enrich at the glass interface and undergoing in-situ chemical bonding. After curing, the silicone layer forms a high-strength chemical bond with the glass substrate, solving the technical problem of poor adhesion between glass and liquid silicone.

[0008] Preferably, the silane coupling agent is a mixture of vinyltriethoxysilane and tetraethyl orthosilicate, and the mass ratio of vinyltriethoxysilane to tetraethyl orthosilicate is 4:1 to 5:1; the polar azeotropic carrier solvent is a mixture of anhydrous ethanol and glacial acetic acid, and the glacial acetic acid accounts for 1.5% to 3.0% of the total mass of the polar azeotropic carrier solvent.

[0009] By employing the above technical solution, anhydrous ethanol in the polar azeotropic carrier solvent provides the driving force for low-boiling-point thermodynamic phase separation, while trace amounts of glacial acetic acid act as an acidic catalyst, promoting the rapid dehydration condensation of the alkoxy groups of the silane coupling agent with the silanol groups on the glass surface. Vinyltriethoxysilane provides vinyl sites for addition reactions with the base liquid silicone rubber, and tetraethyl orthosilicate provides condensation sites for multifunctional silanol groups. The combination of these two components not only increases the crosslinking density at the silicone layer-glass interface, but also, at room temperature, glacial acetic acid forms a coordination effect with the platinum catalyst in the base liquid silicone rubber, inhibiting premature crosslinking at room temperature and ensuring the pot life of the composition.

[0010] Preferably, the base liquid silicone rubber is composed of component A and component B mixed in a 1:1 mass ratio; the raw materials of the base liquid silicone rubber include: vinyl-terminated polydimethylsiloxane, side-chain hydrogen-containing polydimethylsiloxane, surface hydrophobically modified fumed silica, platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex, and 1-ethynyl-1-cyclohexanol.

[0011] By adopting the above technical solution, the base liquid silicone rubber provides a food-grade addition reaction framework and mechanical property support. Vinyl-terminated polydimethylsiloxane and side-chain hydrogen-containing polydimethylsiloxane undergo a hydrosilylation reaction at high temperature to construct a three-dimensional cross-linked network; surface-hydrophobically modified fumed silica provides reinforcement, ensuring that the silicone layer has cushioning and impact-resistant properties.

[0012] Preferably, the preparation method of the interface enrichment agent package includes the following steps: under a nitrogen protective atmosphere, controlling the ambient temperature at 15℃~20℃, adding the prescribed amount of anhydrous ethanol to a sealed reaction vessel, followed by slowly adding the prescribed amount of glacial acetic acid, turning on magnetic stirring and continuously mixing at a speed of 200~300 rpm for 10~15 minutes to obtain a polar azeotropic carrier solvent; keeping the ambient temperature not higher than 20℃, slowly injecting the prescribed amount of the silane coupling agent into the polar azeotropic carrier solvent, increasing the stirring speed to 400~500 rpm and continuously stirring for 30~45 minutes, filtering through a 0.5 micron filter membrane, and then dispensing into an opaque sealed container for refrigeration and storage.

[0013] By adopting the above technical solutions, the anhydrous environment and low temperature conditions are strictly controlled, the introduction of moisture is cut off and the reaction rate is reduced, and the hydrolysis and polycondensation reaction or alcohol esterification side reaction of silane coupling agent is prevented during the mixing and storage stages, so as to ensure that the polar azeotropic carrier solvent and silane coupling agent are in a stable physical dispersion state.

[0014] Preferably, the thickness of the anti-slip buffer layer is 1.5mm to 3.0mm, and the anti-slip buffer layer has a continuous chemical gradient structure in which the concentration of the silane coupling agent gradually decreases from the outside to the inside.

[0015] By employing the above technical solution, silicone layers with a thickness ranging from 1.5mm to 3.0mm provide anti-slip and shock-absorbing functions that meet application requirements. The silane coupling agent migrates and cures unidirectionally from the system interior to the glass interface, forming a continuous chemical gradient structure, eliminating the rigid physical discontinuities produced by traditional multi-layer primer processes. In environments with alternating hot and cold use, such as dishwashers or microwave ovens, the continuous chemical gradient structure effectively disperses and buffers interfacial thermal stress, preventing edge lifting or interlayer peeling of the silicone layer.

[0016] Secondly, the present invention provides a coating and curing process for food-grade silicone anti-slip cushioning bottom glassware, employing the following technical solution: A coating and curing process for a food-grade silicone anti-slip cushioning bottom layer glassware includes the following steps: Composition preparation: Mix the raw material components of the base liquid silicone rubber, then add the interface enrichment agent package, and perform short-time degassing treatment under a set vacuum degree to obtain a self-coating food-grade liquid silicone rubber composition. Substrate pretreatment: The bottom of the glassware is placed in an ultrasonic cleaning tank for degreasing and oil removal and rinsing with pure water, and then sent into a hot air drying tunnel for drying and cooling; the substrate pretreatment process does not involve surface physical activation treatment. Quantitative in-situ coating: Using a fully automatic fluid dispensing machine, the prepared self-bottoming food-grade liquid silicone rubber composition is directly and quantitatively coated onto the bottom surface of the glassware that has not undergone surface physical activation treatment. Nonlinear curing: The coated glassware is placed in a tunnel-type constant temperature oven for stepped nonlinear curing. In the first stage, the ambient temperature is rapidly raised to 65℃~75℃ and kept constant for 3~5 minutes. In the second stage, the temperature is rapidly raised to 135℃~145℃ and kept constant for 8~12 minutes. After curing, the finished product is obtained by naturally cooling at room temperature.

[0017] By adopting the above technical solution, the multi-step substrate construction is simplified into a single-step coating, achieving bubble-free in-situ chemical bonding under thick film conditions. The reaction mechanism of the nonlinear curing process is as follows: Step 1: The first stage is a low-temperature isothermal zone, where the oven temperature is maintained at 65℃~75℃, which is lower than the boiling point of the anhydrous ethanol azeotrope. The polar azeotropic carrier solvent gains heat energy but does not boil or vaporize, driving the silane coupling agent to migrate and penetrate directionally to the glass interface. Glacial acetic acid enriched at the interface plays an in-situ catalytic role, promoting the dehydration condensation reaction between alkoxy groups and silanol groups on the glass surface, thus completing the interfacial bonding.

[0018] Step Two: The second stage is a high-temperature isothermal section, where the temperature rises above the boiling point to 135℃~145℃. Residual low-boiling-point solvents rapidly vaporize and escape from the outer surface of the liquid silicone rubber. The platinum complex catalyst is fully activated, freed from room-temperature coordination inhibition. At the interface, the vinyl groups of the silane coupling agent undergo addition reactions with the hydrogen-containing polysiloxanes in the bulk, simultaneously completing three-dimensional network cross-linking of the liquid silicone rubber bulk, forming a non-porous, highly adhesive, anti-slip buffer layer.

[0019] Preferably, in the composition preparation step, the vacuum degree is controlled to be between -0.05 MPa and -0.085 MPa, and the short-time degassing treatment time is between 1.5 minutes and 3 minutes.

[0020] By employing the above technical solution, the vacuum level is controlled above the critical value of the room temperature saturated vapor pressure of anhydrous ethanol. This removes mechanical bubbles entrained during the mixing process while preventing the polar azeotropic carrier solvent from flashing and evaporating at room temperature under negative pressure. The solvent concentration set in the formulation is maintained to ensure the driving force for subsequent thermodynamic phase separation and interfacial enrichment processes.

[0021] Preferably, in the substrate pretreatment step, the drying parameters of the hot air drying tunnel are: drying at a temperature of 60°C to 80°C for 4 to 6 minutes, and then cooling to below 30°C.

[0022] By employing the above technical solution, surface free moisture at the bottom of the glassware is completely removed. Free moisture causes the silane coupling agent to undergo premature self-hydrolysis and condensation during its migration to the interface, consuming effective reactive functional groups. Coating is performed while controlling the substrate temperature to below 30°C to prevent localized instantaneous cross-linking of the self-coated food-grade liquid silicone rubber composition at the dispensing interface due to high-temperature substrate, which would affect coating uniformity and leveling.

[0023] Preferably, in the quantitative in-situ coating step, the coating morphology is three-point dot coating, outer ring coating, or full bottom surface coating, and the coating thickness is controlled to be 1.5mm to 3.0mm.

[0024] By adopting the above technical solution, the shock absorption and anti-slip requirements of food-grade glassware of different specifications and application scenarios can be met. Within the set thickness range, the polar azeotropic carrier solvent can effectively dissipate, and combined with the step-type nonlinear curing curve, the internal gas blockage caused by surface skin formation is avoided, ensuring the structural density of the thick film coating.

[0025] Preferably, in the nonlinear curing step, the specific heating rate parameters for the stepped nonlinear curing are as follows: the heating rate of the first stage is 8℃ / min to 10℃ / min; the heating rate of the second stage is 15℃ / min to 20℃ / min.

[0026] By adopting the above technical solution, the first stage uses a relatively slow heating rate to match the thermal diffusion kinetics rate of the polar azeotropic carrier solvent inside the silica gel, ensuring that the silane coupling agent has sufficient time to migrate to the glass interface without generating thermal shock; the second stage uses a faster heating rate to quickly establish the three-dimensional network crosslinking of the polymer while the solvent dissipates, thereby improving production efficiency and fixing the continuous chemical gradient structure distribution.

[0027] This invention provides a food-grade silicone anti-slip cushioning bottom glassware and its coating and curing preparation process. It has the following beneficial effects: 1. This invention achieves single-step in-situ coating bonding by adding an interface enrichment agent package composed of a polar azeotropic carrier solvent and a silane coupling agent to a base liquid silicone rubber. In the early stage of heating, the polar azeotropic carrier solvent drives the silane coupling agent to migrate directionally to the glass interface, and dehydration condensation is catalyzed by glacial acetic acid. This technical solution eliminates the plasma or flame surface physical activation step required in traditional processes, as well as the separate coating and drying processes for the primer, shortening the production process, reducing equipment investment in the production line, and improving the mass production efficiency of anti-slip undercoats for glassware.

[0028] 2. The anti-slip buffer underlayer prepared by this invention forms a continuous chemical gradient structure with the concentration of silane coupling agent gradually decreasing from the outside to the inside. The silane coupling agent migrates unidirectionally from the interior of the silicone to the glass interface and undergoes covalent bonding, avoiding the rigid physical interface formed between the glass, the base layer, and the silicone layer in traditional multi-step coating processes. This continuous gradient distribution can effectively disperse the interfacial thermal stress of the material under alternating hot and cold environments, reduce stress concentration, and prevent edge lifting and interlayer peeling of the silicone layer in use scenarios such as dishwashers or microwave ovens, thereby improving the adhesion durability of the product.

[0029] 3. This invention employs a stepped nonlinear curing process to solve the problem of internal pores easily generated during the molding of solvent-containing thick-film silicone. The temperature in the first stage of the process is set below the boiling point of the polar azeotropic carrier solvent, ensuring that the solvent completes interfacial enrichment without boiling or vaporizing. The rapid heating in the second stage promotes effective solvent dissipation and simultaneously completes the three-dimensional network cross-linking of the silicone matrix. Combined with controlled vacuum degassing treatment before coating, internal trapped gas is eliminated under coating thickness conditions of 1.5 mm to 3.0 mm, ensuring the solid density and mechanical cushioning performance of the anti-slip buffer layer. Attached Figure Description

[0030] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0031] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0032] In the core polymer raw materials used in the basic liquid silicone rubber system, the vinyl-terminated polydimethylsiloxane (CAS No.: 68083-19-2) has a dynamic viscosity of 10,000 mPa·s to 20,000 mPa·s at 25°C, and a vinyl mass fraction of 0.12% to 0.16%; the side-chain hydrogen-containing polydimethylsiloxane (CAS No.: 68037-59-2) has a dynamic viscosity of 50 mPa·s to 10 mPa·s at 25°C. 0 mPa·s, active hydrogen mass fraction of 0.7% to 1.2%; specific surface area of ​​surface hydrophobically modified fumed silica (CAS No.: 68909-20-6) of 200 m2 / g to 300 m2 / g; platinum metal mass fraction of platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (CAS No.: 68478-92-2) of 3000 ppm to 5000 ppm. The 1-ethynyl-1-cyclohexanol (CAS No.: 78-27-3), vinyltriethoxysilane (CAS No.: 78-08-0), tetraethyl orthosilicate (CAS No.: 78-10-4), anhydrous ethanol (CAS No.: 64-17-5), glacial acetic acid (CAS No.: 64-19-7), as well as high borosilicate glassware and general-purpose food-grade single-component organosilicon primer used in this invention are all commercially available, conventional, and known products. They are fully disclosed and are well-known to those skilled in the art, and their physicochemical parameters will not be described in detail here.

[0033] Preparation Example 1: This preparation example provides an interface enrichment agent package, including the following steps: Under a dry nitrogen protective atmosphere and with the ambient temperature controlled at 18°C, 53.90 parts by mass of anhydrous ethanol were added to a sealed reactor, followed by the slow dropwise addition of 1.10 parts by mass of glacial acetic acid. Magnetic stirring was started and the mixture was continuously stirred at 250 rpm for 12 minutes to obtain 55.00 parts by mass of a polar azeotropic carrier solvent (of which glacial acetic acid accounted for 2.0% of the total mass of the polar azeotropic carrier solvent). Maintaining the ambient temperature not higher than 20°C, a mixture of 135.00 parts by mass of vinyltriethoxysilane and 30.00 parts by mass of tetraethyl orthosilicate (mass ratio of the two to 4.5:1) was slowly injected into the above polar azeotropic carrier solvent (mass ratio of silane mixture to polar azeotropic carrier solvent to 3:1). The stirring speed was increased to 450 rpm and stirred continuously for 40 minutes. After filtration through a 0.5-micron filter membrane, the mixture was dispensed into opaque, sealed containers and stored at 5°C to 10°C for later use.

[0034] Preparation Example 2: This preparation example provides an interface enrichment agent package, including the following steps: Under a dry nitrogen protective atmosphere and with the ambient temperature controlled at 15°C, 24.625 parts by mass of anhydrous ethanol were added to a sealed reactor, followed by the slow dropwise addition of 0.375 parts by mass of glacial acetic acid. Magnetic stirring was started and the mixture was continuously stirred at 200 rpm for 10 minutes to obtain 25.00 parts by mass of a polar azeotropic carrier solvent (of which glacial acetic acid accounted for 1.5% of the total mass of the polar azeotropic carrier solvent). Maintaining the ambient temperature not higher than 20°C, a mixture of 40.00 parts by mass of vinyltriethoxysilane and 10.00 parts by mass of tetraethyl orthosilicate (mass ratio of the two to 4:1) was slowly injected into the above polar azeotropic carrier solvent (mass ratio of silane mixture to polar azeotropic carrier solvent is 2:1). The stirring speed was increased to 400 rpm and stirred continuously for 30 minutes. After filtration through a 0.5-micron filter membrane, the mixture was dispensed into opaque, sealed containers and stored at 5°C to 10°C for later use.

[0035] Preparation Example 3: This preparation example provides an interface enrichment agent package, including the following steps: Under a dry nitrogen protective atmosphere and with the ambient temperature controlled at 20°C, 14.55 parts by mass of anhydrous ethanol were added to a sealed reactor, followed by the slow dropwise addition of 0.45 parts by mass of glacial acetic acid. Magnetic stirring was started and the mixture was continuously stirred at 300 rpm for 15 minutes to obtain 15.00 parts by mass of a polar azeotropic carrier solvent (of which glacial acetic acid accounted for 3.0% of the total mass of the polar azeotropic carrier solvent). Maintaining the ambient temperature not higher than 20°C, a mixture of 50.00 parts by mass of vinyltriethoxysilane and 10.00 parts by mass of tetraethyl orthosilicate (mass ratio of the two to 5:1) was slowly injected into the above polar azeotropic carrier solvent (mass ratio of silane mixture to polar azeotropic carrier solvent is 4:1). The stirring speed was increased to 500 rpm and the mixture was continuously stirred for 45 minutes. After filtration through a 0.5-micron filter membrane, the mixture was dispensed into opaque, sealed containers and stored at 5°C to 10°C for later use.

[0036] Reference Figure 1 , Figure 1 This is a process flow diagram of the present invention. Example 1: This embodiment provides a food-grade silicone anti-slip cushioning bottom glassware and its coating and curing preparation process, including the following steps: Composition preparation: Component A and component B of the base liquid silicone rubber were mixed at a mass ratio of 1:1, and then the interface enrichment agent package obtained in Preparation Example 1, accounting for 1.2% of the total mass of the base liquid silicone rubber, was added. The mixture was subjected to a short-term degassing treatment for 2 minutes under a medium vacuum of -0.06 MPa to -0.08 MPa (while removing mechanical bubbles, the evaporation of low-boiling-point carrier solvent was avoided) to obtain a self-coating food-grade liquid silicone rubber composition.

[0037] Substrate pretreatment: The bottom of the high borosilicate glassware is placed in an ultrasonic cleaning tank for routine degreasing and rinsing with pure water, and then sent into a hot air drying tunnel to dry at 70°C for 5 minutes. It is then removed and cooled to below 30°C.

[0038] Quantitative in-situ coating: Using a fully automatic fluid dispensing machine, the prepared self-bottom coating food-grade liquid silicone rubber composition is directly applied to the bottom surface of the glassware that has not undergone surface physical activation treatment in a full-coverage manner, with the coating thickness controlled at 2.2mm.

[0039] Nonlinear curing: The coated glassware is placed in a tunnel-type constant temperature oven for stepped nonlinear curing. In the first stage, the ambient temperature is rapidly increased to 70°C at a heating rate of 8°C / min and held at a constant temperature for 4 minutes. In the second stage, the temperature is rapidly increased to 140°C at a heating rate of 18°C / min and held at a constant temperature for 10 minutes. After curing, the glassware is removed from the oven and allowed to cool naturally at room temperature to obtain the finished product.

[0040] Example 2: This embodiment provides a food-grade silicone anti-slip cushioning bottom glassware and its coating and curing preparation process, including the following steps: Composition preparation: Component A and component B of the base liquid silicone rubber were mixed at a mass ratio of 1:1, and then the interface enrichment agent package obtained in Preparation Example 2 was added at a mass ratio of 0.5% of the total mass of the base liquid silicone rubber. The mixture was subjected to a short-term degassing treatment for 3 minutes at a medium vacuum degree of -0.05 MPa to -0.07 MPa (while removing mechanical bubbles, the evaporation of low-boiling-point carrier solvent was avoided) to obtain a self-coating food-grade liquid silicone rubber composition.

[0041] Substrate pretreatment: The bottom of the high borosilicate glassware is placed in an ultrasonic cleaning tank for routine degreasing and rinsing with pure water, and then sent into a hot air drying tunnel to dry at 60°C for 6 minutes. It is then removed and cooled to below 30°C.

[0042] Quantitative in-situ coating: Using a fully automatic fluid dispensing machine, the prepared self-bottoming food-grade liquid silicone rubber composition is directly applied to the bottom surface of the glassware that has not undergone surface physical activation treatment in a three-point dot coating manner, with the coating thickness controlled at 1.5mm.

[0043] Nonlinear curing: The coated glassware is placed in a tunnel-type constant temperature oven for stepped nonlinear curing. In the first stage, the ambient temperature is rapidly increased to 65°C at a heating rate of 10°C / min and held at that temperature for 5 minutes. In the second stage, the temperature is rapidly increased to 135°C at a heating rate of 15°C / min and held at that temperature for 12 minutes. After curing, the glassware is removed from the oven and allowed to cool naturally at room temperature to obtain the finished product.

[0044] Example 3: This embodiment provides a food-grade silicone anti-slip cushioning bottom glassware and its coating and curing preparation process, including the following steps: Composition preparation: Component A and component B of the base liquid silicone rubber were mixed at a mass ratio of 1:1, and then the interface enrichment agent package obtained in Preparation Example 3 was added at a mass ratio of 2.0% of the total mass of the base liquid silicone rubber. The mixture was subjected to a short-term degassing treatment for 1.5 minutes under a vacuum of -0.07 MPa to -0.085 MPa (while removing mechanical bubbles, the evaporation of low-boiling-point carrier solvent was avoided) to obtain a self-coating food-grade liquid silicone rubber composition.

[0045] Substrate pretreatment: The bottom of the high borosilicate glassware is placed in an ultrasonic cleaning tank for routine degreasing and rinsing with pure water. Then it is sent into a hot air drying tunnel and dried at 80°C for 4 minutes. After that, it is taken out and cooled to below 30°C.

[0046] Quantitative in-situ coating: Using a fully automatic fluid dispensing machine, the prepared self-coating food-grade liquid silicone rubber composition is directly coated onto the bottom surface of the glassware that has not undergone surface physical activation treatment in an outer ring coating form, with the coating thickness controlled at 3.0 mm.

[0047] Nonlinear curing: The coated glassware is placed in a tunnel-type constant temperature oven for stepped nonlinear curing. In the first stage, the ambient temperature is rapidly increased to 75°C at a heating rate of 9°C / min and held at that temperature for 3 minutes. In the second stage, the temperature is rapidly increased to 145°C at a heating rate of 20°C / min and held at that temperature for 8 minutes. After curing, the glassware is removed from the oven and allowed to cool naturally at room temperature to obtain the finished product.

[0048] Comparative Example 1: Compared with Example 1, the difference is that no interface enrichment agent package was added, only the main component of the basic liquid silicone rubber was used for coating, and the curing process was changed to direct constant temperature curing at 140°C for 14 minutes, all other aspects are the same.

[0049] Comparative Example 2: Compared with Example 1, the difference is that when preparing the interface enrichment agent package, anhydrous ethanol and glacial acetic acid are not added. Instead, vinyltriethoxysilane and tetraethyl orthosilicate are mixed in the same mass ratio and then directly added to the base liquid silicone rubber. All other aspects are the same.

[0050] Comparative Example 3: Compared with Example 1, the difference is that when preparing the interface enrichment agent package, only anhydrous ethanol was used as the polar azeotropic carrier solvent, and glacial acetic acid was not added; all other aspects are the same.

[0051] Comparative Example 4: Compared with Example 1, the difference is that the first stage of low-temperature enrichment and in-situ anchoring is omitted in the curing process. The coated glassware is directly sent into a constant temperature oven and rapidly heated to 140°C at a heating rate of 18°C / min and cured at a constant temperature for 14 minutes. All other aspects are the same.

[0052] Comparative Example 5: Compared with Example 1, the difference is that the pretreatment step of the substrate is to add plasma surface activation treatment and coating with a general-purpose food-grade single-component silicone primer and air drying. The coating is pure basic liquid silicone rubber without the addition of interface enrichment agent package. The curing process is replaced by direct constant temperature curing at 140°C for 14 minutes. All other processes are the same.

[0053] Test Example 1: In the initial interfacial peel strength test, adhesive strip samples with a width of 10 mm and a length of 150 mm were prepared. Using an electronic universal testing machine, the peel force between the adhesive layer and the glass substrate was tested at a tensile speed of 50 mm / min using the 90-degree peel method. The average peel strength was recorded in N / mm, and the interface failure mode was also recorded. Failure modes were divided into interfacial failure (the adhesive layer peels completely from the glass surface) and cohesive failure (the adhesive layer tears itself, leaving adhesive residue on the glass surface). In the microporosity detection of the adhesive layer cross-section, the cured glassware was cut along the centerline of the bottom adhesive layer, and cross-sectional samples were taken. Using a stereomicroscope at 40x magnification, the number of air bubbles with a diameter greater than 0.1 mm within a 10 square centimeter cross-sectional area was counted. In the thermal shock durability test, the test sample was immersed in a 100°C boiling water bath for 30 minutes, removed, dried, and placed in a -20°C freezer for 30 minutes. Completion of these steps constituted one cycle. After 50 consecutive cycles, the percentage of the perimeter of the adhesive layer edge that detached from the edge was measured out to the total perimeter and recorded as the edge detachment rate. The peel strength after thermal shock was tested using the aforementioned method, and the retention rate of the peel strength after shock relative to the initial peel strength was calculated.

[0054] Table 1 Summary of comprehensive performance test data for the examples and comparative examples

[0055] The test data reflects the synergistic effect of the composition formulation and the nonlinear step-curing process. The initial peel strength of Examples 1 to 3 was above 4.18 N / mm, with 100% cohesive failure as the failure mode and no bubbles in the cross-section. In the low-temperature range of the first curing stage, the temperature is below the boiling point of the polar azeotropic carrier solvent. The solvent does not vaporize and carries the silane coupling agent to the glass interface through a thermodynamic phase separation mechanism, where it migrates and accumulates. The glacial acetic acid accumulated at the interface acts as a catalyst, promoting the dehydration condensation reaction between alkoxy groups and silanol groups on the glass surface, forming covalent bonds for anchoring. During the heating process in the second stage, the solvent dissipates, and the main hydrosilylation reaction completes network locking, preventing gas retention and pore formation within the thick film structure.

[0056] Comparative Example 2, without the addition of a polar solvent as a migration carrier, showed a polysiloxane network encapsulating the silane coupling agent. The coupling agent failed to contact the glass interface, resulting in an initial peel strength of 1.14 N / mm, exhibiting interface failure characteristics. Comparative Example 3, without the addition of glacial acetic acid, lacked acid catalysis for the dehydration condensation reaction at the interface, resulting in a peel strength lower than the examples. Comparative Example 4 employed a high-temperature single-stage curing process. Solvent boiling and flash evaporation disrupted the enrichment process of the coupling agent at the interface. Simultaneously, the cross-linking silicone network trapped the gas, leading to numerous bubbles in the cross-section and a decline in mechanical properties.

[0057] Thermal shock durability tests verified the improvement of the present patent solution on the problem of interfacial thermal stress concentration. Comparative Example 5 employed a multi-layer coating process, with physical interfaces between the substrate and the underlying primer, and between the primer and the silicone matrix. Different physical coatings have different coefficients of thermal expansion. Under alternating hot and cold conditions, shear stress is generated at the interface, resulting in an 18.3% edge warping rate after 50 cycles, and a decline in peel strength. In the examples, the silane coupling agent migrates from the matrix to the interface, forming a continuous chemical gradient structure with a gradually decreasing coupling agent concentration from the outside to the inside after curing. The gradient layer eliminates physical discontinuities, and thermal stress is dissipated and buffered within the gradient region. Examples 1 to 3 showed a warping rate of 0.0% after impact testing, with a strength retention rate of over 95%, indicating improved interfacial stability.

[0058] 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 food-grade silicone anti-slip cushioning bottom glass container, comprising a glass container and an anti-slip cushioning bottom layer disposed on the bottom surface of the glass container, characterized in that, The anti-slip cushioning bottom layer is formed by curing a self-coated food-grade liquid silicone rubber composition. The self-priming food-grade liquid silicone rubber composition comprises the following components in parts by weight: Basic liquid silicone rubber: 100 parts; Interface enrichment agent package: 0.5–2.0 parts; The interface enrichment agent package is composed of a mixture of components comprising the following mass percentages: Silane coupling agent: 66.7%~80.0%; Polar azeotropic carrier solvent: 20.0%~33.3%.

2. The food-grade silicone anti-slip cushioning glassware according to claim 1, characterized in that, The silane coupling agent is a mixture of vinyltriethoxysilane and tetraethyl orthosilicate, and the mass ratio of vinyltriethoxysilane to tetraethyl orthosilicate is 4:1 to 5:

1. The polar azeotropic carrier solvent is a mixed solvent composed of anhydrous ethanol and glacial acetic acid, and the glacial acetic acid accounts for 1.5% to 3.0% of the total mass of the polar azeotropic carrier solvent.

3. The food-grade silicone anti-slip cushioning glassware according to claim 1, characterized in that, The raw materials for the basic liquid silicone rubber include: vinyl-terminated polydimethylsiloxane, side-chain hydrogen-containing polydimethylsiloxane, surface hydrophobically modified fumed silica, platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex, and 1-ethynyl-1-cyclohexanol.

4. The food-grade silicone anti-slip cushioning glassware according to claim 1, characterized in that, The preparation method of the interface enrichment agent package includes the following steps: Under a nitrogen protective atmosphere and with the ambient temperature controlled at 15℃~20℃, anhydrous ethanol of the prescribed amount is added to a sealed reactor, followed by the slow addition of glacial acetic acid of the prescribed amount. Magnetic stirring is started and the mixture is continuously stirred at a speed of 200~300 rpm for 10~15 minutes to obtain a polar azeotropic carrier solvent. Maintaining the ambient temperature not higher than 20℃, the prescribed amount of the silane coupling agent is slowly injected into the polar azeotropic carrier solvent, and the stirring speed is increased to 400~500 rpm for continuous stirring for 30~45 minutes. After filtration through a 0.5-micron filter membrane, the mixture is dispensed into opaque, sealed containers and stored under cold for later use.

5. The food-grade silicone anti-slip cushioning glassware according to claim 1, characterized in that, The thickness of the anti-slip buffer layer is 1.5mm to 3.0mm, and the anti-slip buffer layer has a continuous chemical gradient structure in which the concentration of the silane coupling agent gradually decreases from the outside to the inside.

6. The coating and curing preparation process of the food-grade silicone anti-slip cushioning bottom layer glassware according to any one of claims 1 to 5, characterized in that, Includes the following steps: Composition preparation: Mix the raw material components of the base liquid silicone rubber, then add the interface enrichment agent package, and perform short-time degassing treatment under a set vacuum degree to obtain a self-coating food-grade liquid silicone rubber composition. Substrate pretreatment: The bottom of the glassware is placed in an ultrasonic cleaning tank for degreasing and oil removal and rinsing with pure water, and then sent into a hot air drying tunnel for drying and cooling; the substrate pretreatment process does not involve surface physical activation treatment. Quantitative in-situ coating: Using a fully automatic fluid dispensing machine, the prepared self-bottoming food-grade liquid silicone rubber composition is directly and quantitatively coated onto the bottom surface of the glassware that has not undergone surface physical activation treatment. Nonlinear curing: The coated glassware is placed in a tunnel-type constant temperature oven for stepped nonlinear curing. In the first stage, the ambient temperature is rapidly raised to 65℃~75℃ and kept constant for 3~5 minutes. In the second stage, the temperature is rapidly raised to 135℃~145℃ and kept constant for 8~12 minutes. After curing, the finished product is obtained by naturally cooling at room temperature.

7. The coating and curing preparation process for the food-grade silicone anti-slip cushioning bottom layer of glassware according to claim 6, characterized in that, In the composition preparation step, the vacuum degree is controlled to be between -0.05 MPa and -0.085 MPa, and the short-time degassing treatment time is between 1.5 minutes and 3 minutes, so as to avoid the evaporation of low-boiling-point carrier solvent while extracting mechanical bubbles.

8. The coating and curing preparation process for the food-grade silicone anti-slip cushioning bottom layer of glassware according to claim 6, characterized in that, In the substrate pretreatment step, the drying parameters of the hot air drying tunnel are: drying at a temperature of 60°C to 80°C for 4 to 6 minutes, and then cooling to below 30°C.

9. The coating and curing preparation process for the food-grade silicone anti-slip cushioning bottom layer of glassware according to claim 6, characterized in that, In the quantitative in-situ coating step, the coating morphology is three-point dot coating, outer ring coating, or full bottom surface coating, and the coating thickness is controlled to be 1.5mm to 3.0mm.

10. The coating and curing preparation process for the food-grade silicone anti-slip cushioning bottom layer of glassware according to claim 6, characterized in that, In the nonlinear curing step, the specific heating rate parameters for the stepped nonlinear curing are as follows: The heating rate in the first stage is 8°C / min to 10°C / min; The heating rate in the second stage is 15°C / min to 20°C / min.

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