Packaging film for microprism reflective film

Abstract

The microprism reflective film comprises a microprism layer, the microprism layer comprises a base layer and a microprism unit arranged on the base layer, the packaging film comprises a supporting layer and an adhesive layer welded with the microprism unit, and the thermal deformation temperatures of the supporting layer, the adhesive layer and the microprism layer meet the following conditions: HDTA is greater than HDTB, and HDTA is greater than or equal to HDTC, the | HDTB-HDTC | is less than or equal to 30 DEG C, the HDTA refers to the thermal deformation temperature of the support layer, the HDTB refers to the thermal deformation temperature of the adhesive layer, and the HDTC refers to the thermal deformation temperature of the microprism layer; the bonding layer comprises the following raw materials: polycarbonate resin, ABS resin, polyvinyl butyral, dimethyldihydroxysilane, epoxidized soybean oil, methyltrimethoxysilane, hydroxyethyl methylacrylate and glyceryl monostearate. The packaging film prepared by the invention can form good welding with the microprism layer, so that the bonding strength between layers of the prepared microprism reflective film is high; therefore, the material can be used for preparing road traffic signs.

Description

Technical Field

[0001] The invention belongs to the field of preparation of micro-prismatic reflective films, and in particular relates to a packaging film for micro-prismatic reflective films. Background Art

[0002] The microprismatic reflective film currently used for road traffic signs generally has a microprismatic structure made of polycarbonate. The encapsulation film is a material that encapsulates the microprismatic structure of the microprismatic reflective film. Generally, a hot-melt adhesive layer such as saturated polyester or polyurethane is coated on the substrate, and hot pressing is used to fuse the hot-melt adhesive layer with the microprismatic structure unit during the lamination process. Since hot pressing requires a relatively high temperature to fuse the microprismatic structure unit, this temperature is greater than the coating and drying temperature of the hot-melt adhesive layer, which may cause the interlayer adhesion strength between the hot-melt adhesive layer and the substrate layer to be less than that between the hot-melt adhesive layer and the microprismatic structure layer. The welding strength is poor, resulting in partial or large-area separation of the hot melt adhesive layer and the substrate during subsequent use; in addition, due to the problem of heat conduction (heat from PET-->hot melt adhesive-->microprismatic structure), pseudo welding is prone to occur (that is, the hot melt adhesive has melted, but the microprismatic structure has not melted, and the hot melt adhesive layer softens and adheres to the surface of the microprismatic structure, rather than being welded to each other), and the durability of the welding cannot be guaranteed; if the temperature is too high, the microprismatic structure may be deformed by heat and pressure in the packaging area and the surrounding structures, seriously reducing the retroreflective performance; further improvement is needed. Summary of the invention

[0003] The object of the present invention is to overcome the disadvantages of the prior art and provide a packaging film for a micro-prismatic reflective film.

[0004] The present invention adopts the following technical solution: A packaging film for a microprismatic reflective film, the microprismatic reflective film comprising a microprismatic layer, the microprismatic layer comprising a base layer and a microprismatic unit arranged on the base layer, the packaging film comprising a supporting layer and an adhesive layer fused with the microprismatic unit, the thermal deformation temperatures of the supporting layer, the adhesive layer and the microprismatic layer satisfy the following conditions: HDT A >HDT B , HDT A ≥HDT C , and │HDT B -HDT C │≤30℃, where HDT A Refers to the heat deformation temperature of the support layer, HDT B Refers to the heat deformation temperature of the adhesive layer, HDT C Refers to the thermal deformation temperature of the microprismatic layer; The adhesive layer comprises the following raw materials in parts by weight: 60-70 parts of polycarbonate resin, 20-30 parts of ABS resin, 10-15 parts of polyvinyl butyral, 2-3 parts of dimethyldihydroxy silane, 4-6 parts of epoxy soybean oil, 1-2 parts of methyltrimethoxysilane, 2-3 parts of 2-hydroxyethyl methacrylate, and 1-2 parts of glycerol monostearate.

[0005] Further, the support layer comprises the following raw materials in parts by weight: 80-90 parts of polycarbonate resin, 15-18 parts of titanium dioxide, 8-12 parts of polylactic acid, 2-3 parts of antioxidant, 0.5-1 part of ultraviolet absorber, 2-3 parts of 3-aminopropyltriethoxysilane, 1-2 parts of polyoxyethylene polyoxypropylene amine ether, 1-1.5 parts of tributyl citrate, and 1-2 parts of polybutylene terephthalate.

[0006] Further, its preparation process specifically comprises the following steps: Step 1: Weigh the support layer according to the required parts by weight of its components, place it in an extruder, melt and blend, and extrude and pelletize at 240-260 °C. Step 2: Weigh the adhesive layer according to the required parts by weight of its components, place it in an extruder, melt and blend, and extrude and pelletize at 200-220 °C. Step 3: Calender and form the materials obtained in Step 1 and Step 2 through a coextrusion die to obtain the encapsulation film.

[0007] Further, in Step 3, the die forming temperature of the coextrusion die is 235-245 °C.

[0008] Further, the thickness of the support layer is 30-50 μm, and the thickness of the adhesive layer is 10-30 μm.

[0009] Further, the thickness of the adhesive layer is 20-50% of the height of the microprism unit.

[0010] Further, the light transmittance of the encapsulation film is ≤ 30%.

[0011] As described above for the present invention, compared with the prior art, the beneficial effects of the present invention are as follows: The present application specifically defines the structure of the encapsulation film, provides an adhesive layer on the support layer that bonds to the microprism layer, and further defines the raw material compositions of the support layer and the adhesive layer, such that the heat distortion temperature of the support layer is greater than that of the adhesive layer. During the encapsulation process of the microprism layer, the bonding layer can achieve fusion bonding with the microprism units without affecting the support layer, ensuring that the support layer does not undergo significant deformation, enabling the prepared microprism retroreflective film to maintain a relatively complete form and effectively reducing the retroreflective performance. And through the above method, the fusion bonding fastness and fusion bonding deformation amount between the encapsulation film and the microprism units can be ensured, thereby guaranteeing the bonding fastness between the encapsulation film and the microprism units and ensuring the service life of the prepared microprism retroreflective film. Among them, the bonding layer is mainly composed of polycarbonate resin and ABS resin, with the addition of polyvinyl butyral and 2-hydroxyethyl methacrylate to ensure that the heat distortion temperature of the prepared bonding layer is less than that of the support layer, while having excellent transparency and adhesion to ensure its bonding strength with the microprism layer. Epoxidized soybean oil and glycerol monostearate are introduced and combined with other raw materials, so that when the bonding layer is fused with the microprism layer, the part fused with the microprism layer can stably diffuse to connect with the microprism units, ensuring the fusion bonding deformation amount of the microprism units. Specifically define the raw material composition of the support layer, using polycarbonate resin as the raw material, introducing well-dispersed polylactic acid and titanium dioxide. While ensuring the transparency of the support layer, it can also guarantee the strength of the support layer itself, enabling the prepared encapsulation film to have good fusion bonding fastness with the microprism layer while effectively supporting the microprism layer, ensuring the subsequent use of the microprism retroreflective film. Detailed implementation manners

[0012] The following further describes the present invention through specific implementation manners.

[0013] An encapsulation film for a microprism retroreflective film, wherein the microprism retroreflective film includes a microprism layer and an encapsulation film. The microprism layer includes a base layer and microprism units provided on the base layer. The encapsulation film includes a support layer and an adhesive layer that fuses with the microprism units. Specifically, the heat distortion temperatures of the support layer, the bonding layer, and the microprism layer satisfy the following conditions: HDT A >HDT B ,HDT A ≥HDT C ,and │HDT B - HDT C │≤30 °C, where HDT A refers to the heat distortion temperature of the support layer, HDT B refers to the heat distortion temperature of the adhesive layer, HDT CThe heat distortion temperature of the micro prism layer; further, the light transmittance of the encapsulation film ≤ 30%, the thickness of the support layer is 30 - 50um, the thickness of the adhesive layer is 10 - 30um, and the thickness of the adhesive layer is 20 - 50% of the height of the micro prism unit.

[0014] The adhesive layer comprises the following raw materials in parts by weight: 60 - 70 parts of polycarbonate resin, 20 - 30 parts of ABS resin, 10 - 15 parts of polyvinyl butyral, 2 - 3 parts of dimethyldihydroxy silane, 4 - 6 parts of epoxy soybean oil, 1 - 2 parts of methyltrimethoxysilane, 2 - 3 parts of 2 - hydroxyethyl methacrylate, 1 - 2 parts of glycerol monostearate.

[0015] The support layer comprises the following raw materials in parts by weight: 80 - 90 parts of polycarbonate resin, 15 - 18 parts of titanium dioxide, 8 - 12 parts of polylactic acid, 2 - 3 parts of antioxidant, 0.5 - 1 part of ultraviolet absorber, 2 - 3 parts of 3 - aminopropyltriethoxysilane, 1 - 2 parts of polyoxyethylene polyoxypropylene amine ether, 1 - 1.5 parts of tributyl citrate, 1 - 2 parts of polybutylene terephthalate.

[0016] The micro prism layer comprises the following raw materials in parts by weight: 100 parts of polycarbonate resin, 2 parts of triethylvinylsilane, 1 part of propylene glycol monobutyl ether, 1.5 parts of dioctyl phthalate, 0.5 part of polyoxyethylene fatty alcohol ether, 2 parts of antioxidant.

[0017] Its preparation process specifically comprises the following steps: Step 1, weigh the support layer according to the required parts by weight of its components, place it in an extruder, melt - blend, and extrude and pelletize at 240 - 260°C. Step 2, weigh the adhesive layer according to the required parts by weight of its components, place it in an extruder, melt - blend, and extrude and pelletize at 200 - 220°C. Step 3, calender and form the materials obtained in Step 1 and Step 2 through a co - extrusion die to obtain the encapsulation film, wherein the die forming temperature of the co - extrusion die is 235 - 245°C.

[0018] Example 1 An encapsulation film for a micro prism reflective film, wherein the micro prism reflective film comprises a micro prism layer and an encapsulation film, the micro prism layer comprises a base layer and micro prism units arranged on the base layer, the encapsulation film comprises a support layer and an adhesive layer fused with the micro prism units. Specifically, the heat distortion temperatures of the support layer, the adhesive layer and the micro prism layer satisfy the following conditions: HDT A >HDT B , HDT A ≥HDT C , and │HDT B - HDT C │≤30°C, wherein, HDT A refers to the heat distortion temperature of the support layer, HDTB Refers to the heat distortion temperature of the adhesive layer, HDT C Refers to the heat distortion temperature of the microprism layer; further, the light transmittance of the encapsulation film ≤ 30%, the thickness of the support layer is 30um, the thickness of the adhesive layer is 10um, and the thickness of the adhesive layer is 20% of the height of the microprism unit.

[0019] The adhesive layer comprises the following raw materials in parts by weight: 60 parts of polycarbonate resin, 30 parts of ABS resin, 10 parts of polyvinyl butyral, 3 parts of dimethyldihydroxysilane, 4 parts of epoxy soybean oil, 2 parts of methyltrimethoxysilane, 2 parts of 2-hydroxyethyl methacrylate, 2 parts of glycerol monostearate.

[0020] The support layer comprises the following raw materials in parts by weight: 80 parts of polycarbonate resin, 18 parts of titanium dioxide, 8 parts of polylactic acid, 3 parts of antioxidant, 0.5 part of ultraviolet absorber, 3 parts of 3-aminopropyltriethoxysilane, 1 part of polyoxyethylene polyoxypropylene amine ether, 1.5 parts of tributyl citrate, 1 part of polybutylene terephthalate.

[0021] Its preparation process specifically includes the following steps: Step 1, weigh the support layer according to the required parts by weight of its components, place it in an extruder, melt and blend, and extrude and pelletize at 240 °C; Step 2, weigh the adhesive layer according to the required parts by weight of its components, place it in an extruder, melt and blend, and extrude and pelletize at 200 °C; Step 3, calender and form the materials obtained in Step 1 and Step 2 through a co-extrusion die to obtain an encapsulation film, wherein the die forming temperature of the co-extrusion die is 235 °C.

[0022] Thermally press and laminate the above-prepared encapsulation film with the microprism layer at 210 °C to obtain a microprism reflective film, and perform the following tests on the prepared reflective film: First, place the prepared reflective film 20 cm underwater, soak it at 18 - 28 °C for 24 h, and there is no water ingress except for the edge grid; Second, place the prepared reflective film 20 cm underwater, soak it at 70 °C for 1 h, and there is no water ingress except for the edge grid; Third, coat a two-component pressure-sensitive adhesive (180° peel strength ≧ 20 N / 25 mm) on the release film, dry it and then laminate it with the encapsulation film. After placing it at 24 °C × 48 h, peel off the release film, stick the pressure-sensitive adhesive surface to each other, and after scraping tightly with a squeegee, manually peel it off, and there is no continuous multiple grids peeled off from the encapsulation bottom film.

[0023] Example 2 An encapsulation film for a microprism reflective film, wherein the microprism reflective film comprises a microprism layer and an encapsulation film. The microprism layer comprises a base layer and microprism units provided on the base layer. The encapsulation film comprises a support layer and an adhesive layer fused with the microprism units. Specifically, the heat distortion temperatures of the support layer, the adhesive layer and the microprism layer satisfy the following conditions: HDTA > HDT B ,HDT A ≥HDT C ,and │HDT B - HDT C │≤30 °C, where HDT A refers to the heat distortion temperature of the support layer, HDT B refers to the heat distortion temperature of the adhesive layer, HDT C refers to the heat distortion temperature of the microprism layer; Further, the light transmittance of the encapsulation film ≤ 30%, the thickness of the support layer is 50 um, the thickness of the adhesive layer is 30 um, and the thickness of the adhesive layer is 50% of the height of the microprism unit.

[0024] The adhesive layer includes the following raw materials in parts by weight: 70 parts of polycarbonate resin, 20 parts of ABS resin, 15 parts of polyvinyl butyral, 2 parts of dimethyldihydroxy silane, 6 parts of epoxy soybean oil, 1 part of methyltrimethoxysilane, 3 parts of hydroxyethyl methacrylate, and 1 part of glycerol monostearate.

[0025] The support layer includes the following raw materials in parts by weight: 90 parts of polycarbonate resin, 15 parts of titanium dioxide, 12 parts of polylactic acid, 2 parts of antioxidant, 1 part of ultraviolet absorber, 2 parts of 3-aminopropyltriethoxysilane, 2 parts of polyoxyethylene polyoxypropylene amine ether, 1 part of tributyl citrate, and 2 parts of polybutylene terephthalate.

[0026] Its preparation process specifically includes the following steps: Step 1, weigh the support layer according to the required parts by weight of its components, place it in an extruder, melt and blend, and extrude and pelletize at 260 °C; Step 2, weigh the adhesive layer according to the required parts by weight of its components, place it in an extruder, melt and blend, and extrude and pelletize at 220 °C; Step 3, calender the materials obtained in Step 1 and Step 2 through a coextrusion die to form an encapsulation film, where the die forming temperature of the coextrusion die is 245 °C.

[0027] Thermocompression bond the above-prepared encapsulation film with the microprism layer at 230 °C to obtain a microprism reflective film, and perform the following tests on the prepared reflective film: First, place the prepared reflective film 20 cm underwater, soak it at 18 - 28 °C for 24 h, and there is no water ingress except for the edge grid; Second, place the prepared reflective film 20 cm underwater, soak it at 70 °C for 1 h, and there is no water ingress except for the edge grid; Third, coat a two-component pressure-sensitive adhesive (180° peel strength ≧ 20 N / 25 mm) on the release film, dry it and then bond it with the encapsulation film. After placing it at 24 °C × 48 h, peel off the release film, bond the pressure-sensitive adhesive surfaces together, and scrape tightly with a squeegee, then manually peel it off, and no continuous multiple grids of the encapsulation bottom film are peeled off.

[0028] Example 3 An encapsulation film for a microprism reflective film, wherein the microprism reflective film includes a microprism layer and an encapsulation film. The microprism layer includes a base layer and microprism units provided on the base layer. The encapsulation film includes a support layer and an adhesive layer fused with the microprism units. Specifically, the heat distortion temperatures of the support layer, the adhesive layer, and the microprism layer satisfy the following conditions: HDT A >HDT B , HDT A ≥HDT C , and │HDT B - HDT C │≤30 °C, where HDT A refers to the heat distortion temperature of the support layer, HDT B refers to the heat distortion temperature of the adhesive layer, and HDT C refers to the heat distortion temperature of the microprism layer; further, the light transmittance of the encapsulation film ≤ 30%, the thickness of the support layer is 40 um, the thickness of the adhesive layer is 20 um, and the thickness of the adhesive layer is 30% of the height of the microprism units.

[0029] The adhesive layer includes the following raw materials in parts by weight: 65 parts of polycarbonate resin, 25 parts of ABS resin, 12 parts of polyvinyl butyral, 2.5 parts of dimethyldihydroxy silane, 5 parts of epoxy soybean oil, 1.5 parts of methyltrimethoxysilane, 2.5 parts of hydroxyethyl methacrylate, and 1.5 parts of glycerol monostearate.

[0030] The support layer includes the following raw materials in parts by weight: 85 parts of polycarbonate resin, 16 parts of titanium dioxide, 10 parts of polylactic acid, 2.5 parts of antioxidant, 0.8 part of ultraviolet absorber, 2.5 parts of 3-aminopropyltriethoxysilane, 1.5 parts of polyoxyethylene polyoxypropylene amine ether, 1.2 parts of tributyl citrate, and 1.5 parts of polybutylene terephthalate.

[0031] Its preparation process specifically includes the following steps: Step 1, weigh the support layer according to the required parts by weight of its components, place it in an extruder, melt and blend, and extrude and pelletize at 250 °C; Step 2, weigh the adhesive layer according to the required parts by weight of its components, place it in an extruder, melt and blend, and extrude and pelletize at 210 °C; Step 3, calender and form the materials obtained in Step 1 and Step 2 through a co-extrusion die to obtain the encapsulation film, where the die forming temperature of the co-extrusion die is 240 °C.

[0032] The encapsulation film prepared above is thermocompression laminated with the microprism layer at 220°C to obtain a microprism reflective film. The prepared reflective film is tested as follows: First, the prepared reflective film is placed 20 cm underwater and soaked at 18 - 28°C for 24 h, and there is no water ingress except for the edge grid; Second, the prepared reflective film is placed 20 cm underwater and soaked at 70°C for 1 h, and there is no water ingress except for the edge grid; Third, a two-component pressure-sensitive adhesive (180° peel strength ≥ 20 N / 25 mm) is coated on the release film, dried and then laminated with the encapsulation film. After being placed at 24°C for 48 h, the release film is peeled off, the pressure-sensitive adhesive surface is adhered to each other, and after being tightly scraped with a squeegee, it is manually peeled off, and no continuous multiple grids of the encapsulation bottom film are peeled off.

[0033] It can be seen from the above that the microprism reflective film prepared by thermocompression of the encapsulation film based on this application has high interlayer bonding strength and good long-term durability, and can be used for preparing road traffic signs.

[0034] This application specifically defines the structure of the encapsulation film. An adhesive layer bonded to the microprism layer is provided on the support layer, and the raw material compositions of the support layer and the adhesive layer are further defined, so that the heat distortion temperature of the support layer is greater than that of the adhesive layer. During the encapsulation process of the microprism layer, the bonding layer can achieve welding with the microprism unit without affecting the support layer, ensuring that the support layer does not undergo obvious deformation, so that the prepared microprism reflective film maintains a relatively complete form and effectively reduces the retroreflective performance; and through the above method, the welding fastness and welding deformation amount between the encapsulation film and the microprism unit can be ensured, thereby ensuring the bonding fastness between the encapsulation film and the microprism unit and ensuring the service life of the prepared microprism reflective film; among them, the bonding layer is mainly composed of polycarbonate resin and ABS resin, and polyvinyl butyral and 2-hydroxyethyl methacrylate are added to ensure that the heat distortion temperature of the prepared bonding layer is less than that of the support layer, and at the same time has excellent transparency and adhesion to ensure its bonding strength with the microprism layer; epoxy soybean oil and glycerol monostearate are introduced and combined with other raw materials, so that when the bonding layer is welded to the microprism layer, the part welded to the microprism layer can stably diffuse to be connected with the microprism unit, ensuring the welding deformation amount of the microprism unit.

[0035] The above is only a preferred embodiment of the present invention, and thus cannot limit the scope of implementation of the present invention. That is, equivalent changes and modifications made according to the scope of the present invention application and the content of the specification should still fall within the scope covered by the present invention application.

Claims

1. A packaging film for a microprismatic reflective film, the microprismatic reflective film comprising a microprismatic layer, the microprismatic layer comprising a base layer and microprismatic units arranged on the base layer, characterized in that: It includes a support layer and an adhesive layer welded to the micro-prism unit, and the heat deformation temperature of the support layer, the adhesive layer and the micro-prism layer meets the following conditions: HDT A >HDT B , HDT A ≥HDT C , and │HDT B -HDT C │≤30℃, where HDT A Refers to the heat deformation temperature of the support layer, HDT B Refers to the heat deformation temperature of the adhesive layer, HDT C Refers to the thermal deformation temperature of the microprismatic layer; The bonding layer comprises the following raw materials in parts by weight: 60-70 parts of polycarbonate resin, 20-30 parts of ABS resin, 10-15 parts of polyvinyl butyral, 2-3 parts of dimethyl dihydroxy silane, 4-6 parts of epoxy soybean oil, 1-2 parts of methyl trimethoxy silane, 2-3 parts of hydroxyethyl methacrylate, and 1-2 parts of glyceryl monostearate.

2. The packaging film for microprismatic reflective film according to claim 1, characterized in that: The support layer comprises the following raw materials in parts by weight: 80-90 parts of polycarbonate resin, 15-18 parts of titanium dioxide, 8-12 parts of polylactic acid, 2-3 parts of antioxidant, 0.5-1 part of anti-ultraviolet agent, 2-3 parts of 3-aminopropyl triethoxysilane, 1-2 parts of polyoxyethylene polyoxypropanolamine ether, 1-1.5 parts of tributyl citrate and 1-2 parts of polybutylene terephthalate.

3. The packaging film for microprismatic reflective film according to claim 2, characterized in that: The preparation process specifically comprises the following steps: Step 1, weighing the supporting layer according to the required weight of its components, placing it in an extruder, melt blending, and extruding and granulating at 240-260° C.; Step 2, weighing the adhesive layer according to the required weight of its components, placing it in an extruder, melt blending, and extruding and granulating at 200-220° C.; Step 3, the materials obtained in step 1 and step 2 are calendered through a co-extrusion die to obtain the packaging film.

4. The packaging film for microprismatic reflective film according to claim 3, characterized in that: In step 3, the die molding temperature of the co-extrusion die is 235-245°C.

5. The packaging film for microprismatic reflective film according to claim 1, characterized in that: The thickness of the support layer is 30-50 um, and the thickness of the bonding layer is 10-30 um.

6. The packaging film for microprismatic reflective film according to claim 5, characterized in that: The thickness of the bonding layer is 20-50% of the height of the micro-prism unit.

7. The packaging film for microprismatic reflective film according to claim 1, characterized in that: The light transmittance of the packaging film is ≤30%.