A solvent-free semi-permeable dual-color composite film and a preparation method thereof
By employing a solvent-free adhesive double-layer co-extrusion process, and using nano-semi-permeable modifiers and color masterbatches, environmentally friendly production and efficient molding of dual-color composite films have been achieved. This solves the environmental pollution and stability problems of traditional processes and improves product performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 安徽思瑞盟新材料有限公司
- Filing Date
- 2026-03-26
- Publication Date
- 2026-07-24
AI Technical Summary
Existing technologies for preparing two-color composite films involve the use of solvent-based adhesives, which leads to environmental pollution, health hazards to operators, unstable adhesion between film layers, and high production complexity, making it difficult to achieve precise control over semi-permeability and color saturation.
The solvent-free adhesive is used in a two-layer co-extrusion process. Through the co-extrusion of white and black semi-permeable layers, the transmittance and haze are precisely controlled by nano-semi-permeable regulators and color masterbatches, and the interlayer strength is enhanced by chemical bonding.
Solvent-free preparation was achieved, reducing VOC emissions and production energy consumption, improving the bonding strength between membrane layers and the uniformity of light transmission, and extending the product's service life.
Abstract
Description
Technical Field
[0001] This invention belongs to the field of functional thin film technology, and particularly relates to a solvent-free semi-permeable dual-color composite film and its preparation method. Background Technology
[0002] In the field of semi-permeable colored films for display carriers such as billboards and light boxes, there is a clear market demand for two-color semi-permeable composite films with one side white and the other black. The core process for preparing such two-color composite films is a solvent-based composite process, which involves first preparing two single-color semi-permeable films separately, and then achieving double-layer composite by coating with a solvent-based adhesive. This process has become a key issue restricting product performance and industrial development: This type of process relies on solvent-based adhesives to complete the composite, which not only causes environmental hazards and affects the health of operators due to the emission of volatile organic compounds (VOCs), but also leads to insufficient adhesion stability between film layers due to solvent residue, making it prone to delamination and warping after long-term use, significantly reducing the product's lifespan. At the same time, the use of solvents requires supporting equipment for solvent recovery, drying and curing, which increases the complexity of the production process and energy consumption costs, contradicting the industrial development requirements of green environmental protection, high efficiency and low cost.
[0003] Furthermore, the traditional combination of color masterbatch formulation and solvent compounding makes it difficult to simultaneously achieve precise control of semi-permeability and color saturation, and also fails to solve the problem of synergistic optimization of interlayer bonding and molding process of composite films. There is an urgent need for a technical solution that can eliminate solvent-based adhesives and achieve solvent-free preparation of dual-color semi-permeable composite films through formulation and process innovation, so as to solve the core problems such as environmental defects and insufficient product stability of existing processes. Summary of the Invention
[0004] To address the problems in the prior art, the present invention proposes the following technical solution: A solvent-free semi-permeable dual-color composite film has a double-layer co-extruded structure, comprising a white semi-permeable layer and a black semi-permeable layer that are composited with each other and are free of solvent adhesive; The white semi-permeable layer is composed of the following raw materials in parts by weight: 60-80 parts of base resin, 5-15 parts of white masterbatch, 3-8 parts of semi-permeable conditioner, 0.5-2 parts of antioxidant, and 0.3-1 parts of lubricant; The black semi-permeable layer is composed of the following raw materials in parts by weight: 60-80 parts of base resin, 5-15 parts of black masterbatch, 3-8 parts of semi-permeable conditioner, 0.5-2 parts of antioxidant, and 0.3-1 parts of lubricant. The semi-permeable conditioning agent is one or more of nano-silica, calcium carbonate, or talc, with a particle size of 50-200nm; the white masterbatch uses titanium dioxide as a colorant, and the carrier resin is the same as the substrate resin of the white semi-permeable layer; the black masterbatch uses carbon black as a colorant, and the carrier resin is the same as the substrate resin of the black semi-permeable layer.
[0005] Preferably, the white semi-transparent layer has a light transmittance of 30%-60% and a haze of 20%-50%; the black semi-transparent layer has a light transmittance of 10%-30% and a haze of 20%-50%.
[0006] Preferably, the total thickness of the composite film is 50-200 μm, wherein the thickness of the white semi-permeable layer is 25-100 μm and the thickness of the black semi-permeable layer is 25-100 μm.
[0007] Preferably, the base resin is one or more of polyolefin resin, PET resin, or PVC resin; the antioxidant is one or a combination of hindered phenolic antioxidant and phosphite antioxidant; and the lubricant is one or more of stearic acid, calcium stearate, or polyethylene wax.
[0008] A method for preparing a solvent-free semi-permeable dual-color composite membrane as described above includes the following steps: S1. Raw material pretreatment: The raw materials for the white semi-permeable layer and the black semi-permeable layer are mixed according to the weight ratio to obtain a white mixture and a black mixture. S2, Co-extrusion plasticizing: The white mixture and the black mixture are added to the two feed ports of the twin-screw extruder respectively for heating and plasticizing; S3. Co-extrusion composite molding: The plasticized white melt and black melt are extruded through a co-extrusion die, cooled and shaped, drawn and trimmed to obtain a solvent-free semi-permeable two-color composite film. S4. Finished Product Inspection and Rewinding: Perform performance testing on the composite film, and rewind it after it passes the test.
[0009] Preferably, in step S1, the base resin and color masterbatch need to be dried before mixing the raw materials. The drying temperature is 80-120℃ and the drying time is 2-4h. During the mixing process, the rotation speed is controlled at 300-500r / min and the mixing time is 10-20min.
[0010] Preferably, in step S2, the plasticizing temperature is 160-230℃; in step S3, the temperature of the co-extrusion die is 5-10℃ higher than the plasticizing temperature, the temperature of the cooling roller is 20-40℃, and the traction speed is 5-20m / min.
[0011] The beneficial effects of this invention are as follows: 1. This invention employs a co-extrusion composite process, which allows the melts of the white and black semi-permeable layers to directly fuse and form chemical bonds at high temperatures. This eliminates the need for solvent-based adhesives to achieve double-layer composite, thus eliminating the possibility of solvent evaporation and VOCs generation. It also eliminates the need for solvent recovery, drying, and curing processes and equipment, reducing production energy consumption and equipment investment. Furthermore, the raw materials are directly plasticized and extruded after being uniformly mixed at 300-500 r / min, making the molding process simpler and improving production efficiency.
[0012] 2. Based on the raw material formulation, this invention achieves precise control of the film's transmittance and haze at the raw material level by adding a semi-permeable regulator with a particle size of 50-200nm and controlling its addition amount to 3-8 parts, combined with a ratio of 5-15 parts of the corresponding color masterbatch. This ensures that the white and black semi-permeable layers reach the preset transmittance and haze ranges, guaranteeing the uniformity of light transmission. At the same time, the chemically bonded interlayer structure improves the interlayer bonding strength from the bonding principle, avoiding the problem of unstable interlayer adhesion caused by solvent residue in traditional solvent composites, and fundamentally preventing delamination and warping of the composite film after long-term use. Detailed Implementation
[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.
[0014] A solvent-free, semi-permeable, dual-color composite membrane The composite film has a double-layer co-extruded structure, comprising a white semi-permeable layer and a black semi-permeable layer that are compounded together and bonded without solvent adhesive; The white semi-permeable layer is composed of the following raw materials in parts by weight: 60-80 parts of base resin, 5-15 parts of white masterbatch, 3-8 parts of semi-permeable conditioner, 0.5-2 parts of antioxidant, and 0.3-1 parts of lubricant; The black semi-permeable layer is composed of the following raw materials in parts by weight: 60-80 parts of base resin, 5-15 parts of black masterbatch, 3-8 parts of semi-permeable conditioner, 0.5-2 parts of antioxidant, and 0.3-1 parts of lubricant. in: The substrate resin is one or more of polyolefin resin, PET resin or PVC resin, which provides basic molding and structural support for the composite film. The semi-permeability regulator is one or more of nano-silica, calcium carbonate or talc, with a particle size of 50-200nm, used to precisely control the transmittance and haze of the composite film. The white masterbatch uses titanium dioxide as a colorant, and its carrier resin is the same as the substrate resin of the white semi-permeable layer, ensuring the compatibility between the masterbatch and the substrate resin. The black masterbatch uses carbon black as a colorant, and its carrier resin is the same as the substrate resin of the black semi-permeable layer, thus avoiding delamination and phase separation problems caused by carrier differences. The antioxidant is one or a combination of hindered phenolic antioxidants (such as antioxidant 1010) and phosphite antioxidants (such as antioxidant 168) to improve the anti-aging performance of the composite film and extend its service life. The lubricant is one or more of stearic acid, calcium stearate, or polyethylene wax, which improves the fluidity of the raw material during the plasticizing and molding process and avoids defects such as film sticking to the mold and uneven surface.
[0015] As a preferred embodiment of the present invention, the light transmittance of the white semi-transparent layer is 30%-60%, and the haze is 20%-50%; the light transmittance of the black semi-transparent layer is 10%-30%, and the haze is 20%-50%. This parameter range can ensure the display effect of the composite film under different viewing angles, taking into account both light transmittance and occlusion.
[0016] As a preferred embodiment of the present invention, the total thickness of the composite film is 50-200μm, wherein the thickness of the white semi-permeable layer is 25-100μm and the thickness of the black semi-permeable layer is 25-100μm. The thickness design of the two layers with equal thickness or reasonable ratio ensures the structural balance of the composite film and avoids warping caused by uneven thickness.
[0017] The preparation method of the above-mentioned solvent-free semi-permeable dual-color composite membrane includes the following steps: S1. Raw material pretreatment: First, the base resin, white masterbatch, and black masterbatch are dried at a temperature of 80-120℃ for 2-4 hours to remove moisture from the raw materials and prevent defects such as bubbles and pinholes from appearing in the film after molding. Then, the raw materials of the white semi-permeable layer and the black semi-permeable layer are mixed according to the above weight ratio. During the mixing process, the rotation speed is controlled at 300-500 r / min and the mixing time is 10-20 min to obtain a uniformly mixed white mixture and a black mixture.
[0018] S2. Co-extrusion plasticizing: The white mixture and the black mixture are added to the two independent feed ports of the twin-screw extruder and heated for plasticizing. The plasticizing temperature is adjusted to 160-230℃ according to the type of base resin to ensure that the raw materials are fully plasticized to form a uniform melt.
[0019] S3. Co-extrusion composite molding: The plasticized white melt and black melt are extruded through a co-extrusion die. The temperature of the co-extrusion die is 5-10℃ higher than the plasticizing temperature to ensure the fluidity of the melt in the die. The two melts are initially composited in the die. Then, they are cooled and shaped by a cooling roller at 20-40℃, pulled by a traction machine at 5-20m / min, and trimmed by an edge trimmer to obtain a solvent-free semi-permeable two-color composite film.
[0020] S4. Finished Product Inspection and Rewinding: The thickness, light transmittance, haze, color uniformity, and interlayer bonding strength of the composite film are fully inspected. After passing the inspection, the film is rewound to obtain the finished composite film. Example 1
[0021] Raw material ratio (parts by weight) White semi-permeable layer: 70 parts HDPE resin, 10 parts white masterbatch (60% titanium dioxide content, HDPE as carrier), 5 parts nano silica (100nm particle size), 10101 parts antioxidant, and 0.5 parts calcium stearate. Black semi-permeable layer: 70 parts HDPE resin, 10 parts black masterbatch (50% carbon black content, HDPE as carrier), 5 parts nano silica (100nm particle size), 10101 parts antioxidant, and 0.5 parts calcium stearate.
[0022] Preparation method S1. Raw material pretreatment: HDPE resin, white masterbatch and black masterbatch are dried at 100℃ for 3h. Then, the white semi-permeable layer and black semi-permeable layer raw materials are mixed according to the above ratio. The mixing speed is 400r / min and the mixing time is 15min to obtain white and black mixture. S2, Co-extrusion plasticizing: The two mixtures are added to the two feed ports of the twin-screw extruder, and the plasticizing temperature is controlled at 180℃; S3. Co-extrusion composite molding: The plasticized melt is extruded through a co-extrusion die at a die temperature of 185℃. After being cooled and shaped by a 30℃ cooling roller, it is pulled at a speed of 10m / min and trimmed to obtain a composite film with a total thickness of 100μm (50μm white semi-permeable layer and 50μm black semi-permeable layer). S4. Finished Product Inspection and Rewinding: The composite film is subjected to performance testing. The results are as follows: white semi-permeable layer has a light transmittance of 45% and a haze of 35%; black semi-permeable layer has a light transmittance of 20% and a haze of 35%; interlayer bonding strength is ≥2.5N / 15mm; color uniformity is good; and there are no defects such as bubbles or pinholes. After passing the inspection, the film is rewound. Example 2
[0023] Raw material ratio (parts by weight) White semi-permeable layer: 75 parts PET resin, 8 parts white masterbatch (65% titanium dioxide content, PET carrier), 4 parts nano calcium carbonate (80nm particle size), 1681.5 parts antioxidant, and 0.8 parts polyethylene wax; Black semi-permeable layer: 75 parts PET resin, 8 parts black masterbatch (carbon black content 55%, carrier is PET), 4 parts nano calcium carbonate (particle size 80nm), 1681.5 parts antioxidant, and 0.8 parts polyethylene wax.
[0024] Preparation method S1. Raw material pretreatment: Dry PET resin, white masterbatch and black masterbatch at 120℃ for 4 hours, then mix the raw materials according to the above ratio, mix at 500 r / min for 12 min to obtain white and black mixture. S2, Co-extrusion plasticizing: The two mixtures are added to the two feed ports of the twin-screw extruder, and the plasticizing temperature is controlled at 220℃; S3. Co-extrusion composite molding: The plasticized melt is extruded through a co-extrusion die at a die temperature of 225℃. After being cooled and shaped by a 35℃ cooling roller, it is pulled at a speed of 8m / min and trimmed to obtain a composite film with a total thickness of 120μm (60μm white semi-permeable layer and 60μm black semi-permeable layer). S4. Finished Product Inspection and Rewinding: The composite film is subjected to performance testing. The results are as follows: white semi-permeable layer has a light transmittance of 40% and a haze of 30%; black semi-permeable layer has a light transmittance of 15% and a haze of 30%; interlayer bonding strength is ≥3.0N / 15mm; color uniformity is good; and there are no defects such as bubbles or pinholes. After passing the inspection, the film is rewound. Example 3
[0025] Raw material ratio (parts by weight) White semi-permeable layer: 65 parts PVC resin, 12 parts white masterbatch (55% titanium dioxide content, PVC as carrier), 6 parts talc (150nm particle size), 0.8 parts antioxidant 1010, and 0.6 parts stearic acid; Black semi-permeable layer: 65 parts PVC resin, 12 parts black masterbatch (carbon black content 45%, carrier is PVC), 6 parts talc (particle size 150nm), 0.8 parts antioxidant 1010, and 0.6 parts stearic acid.
[0026] Preparation method S1. Raw material pretreatment: Dry PVC resin, white masterbatch and black masterbatch at 80℃ for 2 hours, then mix the raw materials according to the above ratio, mix at 350 r / min for 18 min to obtain white and black mixture. S2, Co-extrusion plasticizing: The two mixtures are added to the two feed ports of the twin-screw extruder, and the plasticizing temperature is controlled at 170℃; S3. Co-extrusion composite molding: The plasticized melt is extruded through a co-extrusion die at a die temperature of 175℃. After being cooled and shaped by a 25℃ cooling roller, it is pulled at a speed of 12m / min and trimmed to obtain a composite film with a total thickness of 80μm (40μm white semi-permeable layer and 40μm black semi-permeable layer). S4. Finished Product Inspection and Rewinding: The composite film is subjected to performance testing. The results are as follows: white semi-permeable layer has a light transmittance of 50% and a haze of 40%; black semi-permeable layer has a light transmittance of 25% and a haze of 40%; interlayer bonding strength ≥2.0N / 15mm; good color uniformity; and no defects such as bubbles or pinholes. After passing the inspection, the film is rewound.
[0027] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it.
Claims
1. A solvent-free, semi-permeable, dual-color composite film, characterized in that, It has a double-layer co-extruded structure, consisting of a white semi-permeable layer and a black semi-permeable layer that are composite with each other and have no solvent adhesive; The white semi-permeable layer is composed of the following raw materials in parts by weight: 60-80 parts of base resin, 5-15 parts of white masterbatch, 3-8 parts of semi-permeable conditioner, 0.5-2 parts of antioxidant, and 0.3-1 parts of lubricant; The black semi-permeable layer is composed of the following raw materials in parts by weight: 60-80 parts of base resin, 5-15 parts of black masterbatch, 3-8 parts of semi-permeable conditioner, 0.5-2 parts of antioxidant, and 0.3-1 parts of lubricant. The semi-permeable conditioning agent is one or more of nano-silica, calcium carbonate, or talc, with a particle size of 50-200nm; the white masterbatch uses titanium dioxide as a colorant, and the carrier resin is the same as the substrate resin of the white semi-permeable layer; the black masterbatch uses carbon black as a colorant, and the carrier resin is the same as the substrate resin of the black semi-permeable layer.
2. The solvent-free semi-permeable dual-color composite membrane according to claim 1, characterized in that, The white semi-transparent layer has a light transmittance of 30%-60% and a haze of 20%-50%; the black semi-transparent layer has a light transmittance of 10%-30% and a haze of 20%-50%.
3. The solvent-free semi-permeable dual-color composite membrane according to claim 1, characterized in that, The total thickness of the composite film is 50-200 μm, of which the thickness of the white semi-permeable layer is 25-100 μm and the thickness of the black semi-permeable layer is 25-100 μm.
4. The solvent-free semi-permeable dual-color composite membrane according to claim 1, characterized in that, The base resin is one or more of polyolefin resin, PET resin or PVC resin; the antioxidant is one or a combination of hindered phenolic antioxidant and phosphite antioxidant; the lubricant is one or more of stearic acid, calcium stearate or polyethylene wax.
5. A method for preparing a solvent-free semi-permeable dual-color composite membrane as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Raw material pretreatment: The raw materials for the white semi-permeable layer and the black semi-permeable layer are mixed according to the weight ratio to obtain a white mixture and a black mixture. S2, Co-extrusion plasticizing: The white mixture and the black mixture are added to the two feed ports of the twin-screw extruder respectively for heating and plasticizing; S3. Co-extrusion composite molding: The plasticized white melt and black melt are extruded through a co-extrusion die, cooled and shaped, drawn and trimmed to obtain a solvent-free semi-permeable two-color composite film. S4. Finished Product Inspection and Rewinding: Perform performance testing on the composite film, and rewind it after it passes the test.
6. The preparation method according to claim 5, characterized in that, In step S1, the base resin and color masterbatch need to be dried before mixing the raw materials. The drying temperature is 80-120℃ and the drying time is 2-4h. During the mixing process, the rotation speed is controlled at 300-500r / min and the mixing time is 10-20min.
7. The preparation method according to claim 5, characterized in that, In step S2, the plasticizing temperature is 160-230℃; in step S3, the temperature of the co-extrusion die is 5-10℃ higher than the plasticizing temperature, the temperature of the cooling roller is 20-40℃, and the traction speed is 5-20m / min.