Glass surface treatment method capable of resisting high-temperature and high-pressure injection molding shear force
By cleaning and dual-phase activation of the glass substrate, a three-band self-locking polymer adhesive layer is formed, which solves the problem of easy delamination and detachment of the glass-plastic interface during high-temperature and high-pressure injection molding, and achieves stable bonding and high yield in high-temperature and high-pressure injection molding.
Patent Information
- Application Number
- CN202610363817.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-24
- Publication Date
- 2026-05-12
AI Technical Summary
During high-temperature and high-pressure injection molding, the glass-plastic interface is prone to delamination and detachment. Existing technologies suffer from insufficient temperature resistance, numerous process steps, inadequate stability, poor mass production adaptability, and weak interface shear resistance.
The glass substrate is cleaned and activated in two phases to form a three-band self-locking polymer adhesive layer, including a glass anchoring layer, a shear buffer layer and a plastic affinity layer. A stable self-crosslinking network is formed through directional leveling and staged pre-curing, achieving high-temperature and high-pressure bonding between glass and plastic.
It improves the heat resistance and shear strength of the glass-plastic interface, reduces interface delamination and peeling, and ensures the stability and yield of the injection molding process.
Smart Images
Figure CN122008475A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of glass surface treatment technology, specifically to a glass surface treatment method that can resist the shear force of high-temperature and high-pressure injection molding. Background Technology
[0002] Glass products, used in consumer electronics, instrument housings, automotive parts, sealed windows, and functional trim, often require injection molding to encapsulate them with plastics to achieve a unified appearance, structural strength, and sealing performance. However, existing glass has low surface energy, strong surface chemical inertness, and poor compatibility with injection-molded plastics. Furthermore, during the injection molding process, it is simultaneously subjected to high temperatures, gate impact, high-pressure filling, and shear flow, making it highly susceptible to the following problems: interfacial delamination between the glass and plastic; cracking at the interface; detachment after injection molding; decreased sealing performance, insufficient strength, and reduced yield of the finished product.
[0003] Existing solutions typically rely on primers, conventional silane coupling agents, plasma treatment, flame treatment, or single adhesive systems. While these solutions can improve adhesion in some scenarios, they still suffer from insufficient temperature resistance, numerous process steps, inadequate stability, poor mass production adaptability, and weak interfacial shear resistance under high-temperature, high-pressure injection molding shear environments. Particularly when glass and plastic are simultaneously subjected to thermal stress and flow shear stress, single interfacial activation methods struggle to maintain effective bonding over the long term. Summary of the Invention
[0004] To overcome the shortcomings of the prior art, the present invention provides the following technical solution: a glass surface treatment method that can resist high temperature and high pressure injection molding shear force, comprising the following steps: S1, cleaning and drying the glass substrate; S2, performing biphase activation on the cleaned glass substrate to form a glass surface with high surface reactivity; S3, coating the biphase activated glass surface with a film-forming liquid and forming a three-band self-locking polymer adhesive layer by directional leveling, wherein the three-band self-locking polymer adhesive layer consists of a glass anchoring layer near the glass substrate, a shear buffer layer in the middle, and a plastic affinity layer near the injection molding plastic; S4, pre-curing the three-band self-locking polymer adhesive layer to form a stable self-crosslinking network; S5, placing the pre-cured glass substrate in an injection mold for injection molding, so that the injection molding plastic and the plastic affinity layer complete interfacial bonding under high temperature and high pressure conditions.
[0005] Preferably, the film-forming liquid comprises the following components in parts by weight: 48 to 58 parts of o-bisphosphonic acid-terminated aromatic polyetherimide resin; 12 to 20 parts of benzoxazine-maleimide latent crosslinking resin; 8 to 16 parts of styrene-acrylate-vinylpyrrolidone copolymer; 4 to 8 parts of intraimide-terminated flexible segment resin; 1 to 4 parts of surface-grafted nano-silica; 0.3 to 1.0 parts of latent acid release agent; and the balance being solvent.
[0006] Preferably, the directional leveling includes the following conditions: the direction of movement of the coating head is consistent with the direction of flow of the injection molten metal, and the operating speed of the coating head is 30 mm / s to 80 mm / s; an uncoated edge band with a width of 1.0 mm to 2.0 mm is provided around the glass substrate.
[0007] Preferably, the biphase activation includes alkaline mist activation and ozone ultraviolet activation, and the alkaline mist activation is performed before the ozone ultraviolet activation.
[0008] Preferably, the alkaline mist activation conditions are: activation solution temperature of 35°C to 45°C, and activation time of 40 to 90 seconds; the ozone ultraviolet activation conditions are: 185 nm ozone activation for 2 to 5 minutes, and 254 nm ultraviolet activation for 1 to 3 minutes.
[0009] Preferably, the pre-curing includes a first-stage pre-curing and a second-stage pre-curing. The conditions for the first-stage pre-curing are 80 to 110 degrees Celsius for 3 to 6 minutes, and the conditions for the second-stage pre-curing are 120 to 150 degrees Celsius for 1 to 3 minutes.
[0010] Preferably, the total thickness of the three-band self-locking polymer adhesive layer is 8 micrometers to 18 micrometers, wherein the thickness of the glass anchoring layer is 1 micrometer to 3 micrometers, the thickness of the shear buffer layer is 4 micrometers to 10 micrometers, and the thickness of the plastic affinity layer is 2 micrometers to 5 micrometers.
[0011] Preferably, the injection molding plastic is one of PC, ABS, PC / ABS, PA6, PBT, and PPS, and the temperature of the injection molding barrel is 220 degrees Celsius to 330 degrees Celsius, and the injection pressure is 80 MPa to 150 MPa.
[0012] Preferably, the glass anchoring layer is formed by enriching the o-bisphosphonic acid-terminated aromatic polyetherimide resin, the shear buffer layer is formed by enriching the benzoxazine-maleimide latent crosslinking resin and the intraimide-terminated flexible segment resin, and the plastic affinity layer is formed by enriching the styrene-acrylate-vinylpyrrolidone copolymer.
[0013] Compared with the prior art, the present invention has the following advantages: (1) The glass surface bonding layer of the present invention is not a temporary activation layer, but forms a stable polymer self-crosslinking network with higher heat resistance and stability; (2) The glass end, stress end and plastic end of the present invention are completed in the same layer, and the interface stress transmission is smoother; (3) The present invention has higher coating uniformity and less edge overflow and local accumulation through directional leveling and edge sealing tape design; (4) The present invention has sufficient initial strength before injection molding impact through staged pre-curing, and is not easily washed away and damaged during injection molding. Attached Figure Description
[0014] Figure 1 This is a flowchart of the overall process of the method of the present invention. Detailed Implementation
[0015] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0016] The technical problem to be solved by this invention is how to overcome the problems of poor adhesion, easy delamination and easy detachment of glass and injection-molded plastic under high temperature and high pressure injection molding conditions, and to provide a glass surface treatment solution that is simple in process, has strong adhesion, is resistant to high temperature injection molding, and is suitable for mass production.
[0017] The technical solution adopted in this invention is as follows: The glass substrate is cleaned to remove surface oil, dust, mold release residue, and weakly adsorbed contaminants. The cleaned glass substrate undergoes biphasic activation: first, alkaline mist activation increases the density of reactive sites on the glass surface; then, ozone ultraviolet activation further enhances surface energy and surface activity. A film-forming liquid with a specific formulation is coated onto the glass surface to form a three-band self-locking polymer adhesive layer. Through directional leveling, the adhesive layer forms a gradient structure on the glass surface, consisting of a glass anchoring layer, a shear buffer layer, and a plastic affinity layer. Staged pre-curing is performed to form a stable self-crosslinking network within the adhesive layer while retaining sufficient interfacial active sites. The treated glass substrate is placed in an injection mold for injection molding, utilizing interfacial wetting under high temperature and pressure and subsequent cooling and shrinkage to achieve a high-strength bond.
[0018] This invention unifies the three previously separate functions of glass and plastic into a single layer: a glass anchoring layer (responsible for securing the glass surface); a shear buffer layer (responsible for absorbing injection molding shear and thermal stress); and a plastic affinity layer (responsible for forming good wetting and fusion with the injection-molded plastic). This is not achieved by simply adding two or three separate layers, but rather through a single coating, a single directional leveling process, and a single curing to naturally form gradient zones. In this way, the high-pressure shear during injection molding does not directly impact the glass interface; instead, it is first absorbed by the shear buffer layer and then transitions to the injection-molded plastic through the plastic affinity layer, thus significantly improving interface stability.
[0019] Select the glass substrate to be injection molded. The glass substrate can be flat glass, curved glass, display cover glass, instrument window glass, or functional decorative glass. The glass surface should be cleaned and decontaminated beforehand.
[0020] This can be achieved through the following methods and steps: The cleaning steps are as follows: First, immerse the glass in a 2.0% by weight neutral cleaning solution and ultrasonically clean it for 6 minutes at 45 to 50 degrees Celsius; then rinse it with pure water for 2 minutes; wipe it with ethanol for 1 minute; and finally dry it at 85 degrees Celsius for 12 minutes.
[0021] Two-phase activation: Two-phase activation consists of alkaline mist activation and ozone-UV activation. During alkaline mist activation, the glass surface is exposed to an activation solution atomization environment at 35°C to 45°C for 40 to 90 seconds. The activation solution is preferably a weakly alkaline solution to increase the number of reaction sites on the glass surface. Immediately after alkaline mist activation, ozone-UV activation is performed, using 185 nm ozone for 2 to 5 minutes, followed by 254 nm UV activation for 1 to 3 minutes, further forming a highly active interface state on the glass surface. The purpose of two-phase activation is not simply cleaning, but simultaneously removing surface contaminants, increasing surface energy, and activating surface reaction sites, providing a strong anchoring foundation for the subsequent polymer adhesive layer.
[0022] Composition of the film-forming solution: The film-forming solution, based on 100 parts by weight, consists of the following components: 48 to 58 parts of o-bisphosphonic acid-terminated aromatic polyetherimide resin; 12 to 20 parts of benzoxazine-maleimide latent crosslinking resin; 8 to 16 parts of styrene-acrylate-vinylpyrrolidone copolymer; 4 to 8 parts of intraimide-terminated flexible segment resin; 1 to 4 parts of surface-grafted nano-silica; 0.3 to 1.0 parts of latent acid release agent; and the balance of solvent.
[0023] The formulation comprises: o-bisphenol phosphonic acid-terminated aromatic polyetherimide resin as the glass anchoring host, whose molecular end groups can form a high-strength anchor with the activated glass surface; benzoxazine-maleimide latent crosslinking resin as a heat-resistant skeleton to improve the thermal and structural stability of the interface layer during injection molding; styrene-acrylate-vinylpyrrolidone copolymer as a plastic affinity host to enhance wettability and compatibility with plastics such as PC, ABS, PC / ABS, PA6, PBT, and PPS; internal imide-terminated flexible segment resin to construct the tough zone of the shear buffer layer; surface-grafted nano-silica to construct a microscale skeleton and reduce shrinkage crack propagation; and latent acid release agent to trigger end crosslinking during pre-curing and subsequent injection molding thermal history. It should be noted that this formulation differs from conventional silane primer systems; the main anchoring structure is a non-silane main chain anchoring system, and the interface layer itself is a polymer functional layer, not a low-molecular-weight temporary primer.
[0024] Coating and Oriented Leveling: The film-forming liquid is uniformly coated onto the glass surface after dual-phase activation treatment. The preferred coating method is scraping, slot coating, or spraying. During coating, the coating head moves in the same direction as the injection melt flow, with a speed of 30 to 80 millimeters per second. This is to allow the adhesive layer to form an orientation structure along the future injection shear direction during film formation, preventing the shear force during subsequent injection from directly tearing the interface, but instead dispersing it along the internal orientation structure. Simultaneously, a 1.0 to 2.0 millimeter wide uncoated edge sealing strip is applied around the glass substrate to prevent the coating from being squeezed out to the edges during mold cavity pressing, ensuring neat finished product boundaries and reducing edge stress concentration.
[0025] Formation of the Three-Band Self-Locking Polymer Adhesive Layer: After coating, the film-forming liquid automatically forms a three-band structure during evaporation, leveling, and localized reaction: The first band is a glass anchoring layer, 1 to 3 micrometers thick, located close to the glass substrate and enriched with o-bisphosphonic acid-terminated aromatic polyetherimide resin; the second band is a shear buffer layer, 4 to 10 micrometers thick, enriched with benzoxazine-maleimide latent crosslinking resin and internal imide-terminated flexible segment resin; the third band is a plastic affinity layer, 2 to 5 micrometers thick, enriched with styrene-acrylate-vinylpyrrolidone copolymer. The key point is that the same material spontaneously forms bands during film formation due to differences in surface energy, solvent evaporation rates, and pre-curing temperatures, rather than through multiple layering and overcoating. This reduces the number of interlayer interfaces and lowers the risk of internal delamination.
[0026] Pre-curing consists of two stages: Stage 1 pre-curing: 80°C to 110°C, lasting 3 to 6 minutes; Stage 2 pre-curing: 120°C to 150°C, lasting 1 to 3 minutes. Stage 1 is used to remove residual solvent and complete the initial network construction; Stage 2 is used to lock the three-band structure and improve the heat resistance stability of the surface layer. After pre-curing, the adhesive layer surface does not exhibit sagging, collapse, or obvious pinholes, and maintains a stable film state before injection molding.
[0027] Injection Molding Overmolding: The pre-cured glass substrate is placed into an injection mold and then overmolded. The injection plastic is selected from PC, ABS, PC / ABS, PA6, PBT, and PPS. The barrel temperature is controlled between 220°C and 330°C, and the injection pressure is controlled between 80 MPa and 150 MPa. During injection molding, the high-temperature melt first contacts the plastic affinity layer, which has good wettability and compatibility with the melt. Subsequently, the melt shear stress is absorbed and dispersed by the shear buffer layer. Finally, the interfacial load is transferred to the glass anchoring layer, which forms a stable bond with the glass substrate. Therefore, the interface avoids the instantaneous peeling, thermal shock delamination, and cooling-induced detachment commonly seen in traditional methods.
[0028] The working principle is as follows: First, chemical anchoring. Specific end groups in the glass anchoring layer form a stable bond with the glass surface, preventing interfacial slippage. Second, shear dissipation. The shear buffer layer has a structure that combines rigidity and flexibility, preventing brittle fracture under high-speed flow shear during injection molding. Instead, it disperses stress through chain segment rearrangement and micro-area energy dissipation. Third, plastic wetting transition. The plastic affinity layer has good compatibility with the injection-molded plastic, allowing the melt to spread and adhere quickly, reducing voids and unwetted areas. Because these three mechanisms exist simultaneously, it does not rely on a single coupling agent or a single primer, but rather solves the three problems of difficult glass adhesion, easy tearing under shear, and easy delamination due to thermal shock through a hierarchical locking network.
Claims
1. A glass surface treatment method capable of resisting the shear force of high-temperature and high-pressure injection molding, characterized in that, Includes the following steps: S1. Clean and dry the glass substrate; S2. Perform two-phase activation on the cleaned glass substrate to form a glass surface with high surface reactivity; S3. Coat the glass surface after dual-phase activation with a film-forming liquid and form a three-band self-locking polymer adhesive layer by directional leveling. The three-band self-locking polymer adhesive layer consists of a glass anchoring layer close to the glass substrate, a shear buffer layer in the middle, and a plastic affinity layer close to the injection-molded plastic. S4. Pre-curing the three-band self-locking polymer adhesive layer to form a stable self-crosslinking network. S5. The pre-cured glass substrate is placed in an injection mold for injection molding and coating, so that the injection-molded plastic and the plastic affinity layer complete the interface bonding under high temperature and high pressure conditions.
2. The glass surface treatment method according to claim 1, which can resist the shear force of high temperature and high pressure injection molding, is characterized in that, The film-forming solution comprises the following components in parts by mass: 48 to 58 parts of o-bisphosphonic acid-terminated aromatic polyetherimide resin; 12 to 20 parts of benzoxazine-maleimide latent crosslinking resin; 8 to 16 parts of styrene-acrylate-vinylpyrrolidone copolymer; 4 to 8 parts of a lactimide-terminated flexible segment resin; 1 to 4 parts of surface-grafted nano-silica; Latent acid release agent 0.3 to 1.0 parts; Solvent balance.
3. The glass surface treatment method according to claim 2, which can resist the shear force of high temperature and high pressure injection molding, is characterized in that, The directional leveling includes the following conditions: The coating head moves in the same direction as the injection melt flow, and the coating head runs at a speed of 30 mm / s to 80 mm / s. The glass substrate is surrounded by an uncoated edge band with a width of 1.0 mm to 2.0 mm.
4. A glass surface treatment method capable of resisting high-temperature and high-pressure injection molding shear forces according to claim 3, characterized in that, The biphase activation includes alkaline mist activation and ozone ultraviolet activation, with the alkaline mist activation performed before the ozone ultraviolet activation.
5. A glass surface treatment method according to claim 4 that can resist high temperature and high pressure injection molding shear force, characterized in that, The conditions for alkaline mist activation are: activation solution temperature of 35 to 45 degrees Celsius and activation time of 40 to 90 seconds; the conditions for ozone ultraviolet activation are: 185 nm ozone activation for 2 to 5 minutes and 254 nm ultraviolet activation for 1 to 3 minutes.
6. A glass surface treatment method according to claim 5 that can resist high temperature and high pressure injection molding shear force, characterized in that, The pre-curing includes a first-stage pre-curing and a second-stage pre-curing. The conditions for the first-stage pre-curing are 80 to 110 degrees Celsius for 3 to 6 minutes, and the conditions for the second-stage pre-curing are 120 to 150 degrees Celsius for 1 to 3 minutes.
7. A glass surface treatment method according to claim 6 that can resist high temperature and high pressure injection molding shear force, characterized in that, The total thickness of the three-band self-locking polymer adhesive layer is 8 to 18 micrometers, of which the thickness of the glass anchoring layer is 1 to 3 micrometers, the thickness of the shear buffer layer is 4 to 10 micrometers, and the thickness of the plastic affinity layer is 2 to 5 micrometers.
8. A glass surface treatment method according to claim 7 that can resist high temperature and high pressure injection molding shear force, characterized in that, The injection molding plastic is one of PC, ABS, PC / ABS, PA6, PBT, and PPS. The temperature of the injection molding barrel is 220°C to 330°C, and the injection pressure is 80 MPa to 150 MPa.
9. A glass surface treatment method according to claim 8 that can resist high temperature and high pressure injection molding shear force, characterized in that, The glass anchoring layer is formed by enriching the o-bisphosphonic acid-terminated aromatic polyetherimide resin, the shear buffer layer is formed by enriching the benzoxazine-maleimide latent crosslinking resin and the intramimide-terminated flexible segment resin, and the plastic affinity layer is formed by enriching the styrene-acrylate-vinylpyrrolidone copolymer.