A biodegradable composite material and a method of preparation, electrochemically deposited aluminium film

Abstract

The application discloses a biodegradable composite material, and raw materials for preparation include polylactic acid 60-78%, toughening agent 20-30%, transparent inorganic substance 1-10%, and cellulose 0.1-0.5% in percentage by weight. The application adopts block polyether amide resin as the toughening agent, and the block polyether amide resin acts together with the PLA resin, and then high-transparency inorganic substance zinc sulfide is added, so that the obtained composite material has good tensile toughness and good heat resistance. Meanwhile, the transparency and puncture resistance of the biodegradable composite material film are improved, and the tensile toughness and heat resistance are obviously improved. The application is degradable, has good adhesion, high pattern integrity, and good slitting performance, and does not affect the holographic stamping performance of the anodized aluminum film.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of printing, in particular to a biodegradable composite material and a preparation method, and an electrochemical aluminum film. BACKGROUND

[0002] Holographic stamping technology is widely welcomed because of its excellent surface decoration effect and is widely used on various outer packaging materials. The electroplated aluminum film in the holographic stamping process is mostly made of PET material and does not have degradability. The electroplated aluminum waste film generated during the stamping process has caused serious garbage disposal problems, and is mostly disposed of by incineration, which can produce environmental pollutants such as dioxins. Therefore, it is crucial to develop a biodegradable electrochemical aluminum film that does not affect the holographic stamping effect.

[0003] Chinese patent CN112829489B discloses a packaging box printing process of UV flash three-dimensional stamping flowers, which selects components such as hydrogen silicone oil, vinyl silicone oil, perfluoroalkyl ethylene, and diethylaminoethyl methacrylate. Under the action of a platinum catalyst (chloroplatinic acid-isopropyl alcohol mixed solution), a silicon hydrogen addition reaction occurs, thereby forming a mutually cross-linked organic silicon release layer that has excellent release demolding effect when used, but does not have a degradation effect. Chinese utility model patent CN217778169U discloses a holographic true color stamping film, which has a release layer, an information layer, a color layer, an aluminum plating layer, and a hot stamping adhesive layer arranged in sequence on the base film, and can achieve good and precise true color overprint, but does not have degradation performance. SUMMARY

[0004] In order to develop a biodegradable electrochemical aluminum film that does not affect the holographic stamping effect, the first aspect of the present application provides a biodegradable composite material, the preparation raw materials include, by weight percentage, polylactic acid 60-78%, toughening agent 20-30%, transparent inorganic matter 1-10%, and cellulose 0.1-0.5%.

[0005] As a preferred embodiment, the melt index of the polylactic acid under the condition of 190°C and 2.16kg is 1-6g / 10min.

[0006] As a preferred embodiment, the toughening agent is a block polyether amide resin.

[0007] As a preferred embodiment, the cellulose is ethyl cellulose, and the mass fraction of ethoxyl groups in the ethyl cellulose is 44-47.9%.

[0008] As a preferred embodiment, the viscosity of the ethyl cellulose at 25°C is 3-5.5mPa·s.

[0009] As a preferred embodiment, the transparent inorganic substance is selected from at least one of sodium oxide, silicon carbide, titanium oxide, zinc oxide, zinc sulfide, boron nitride, and aluminum oxide.

[0010] As a preferred embodiment, the transparent inorganic substance is zinc sulfide.

[0011] The inventors found in the experiment that, after blending polylactic acid with inorganic materials such as nanosilica and graphene, the tensile toughness and heat resistance of the prepared blended material are obviously improved, but the transparency of the composite material is seriously affected, which cannot meet the requirements of a printing substrate.

[0012] The inventors found in the experiment that, after using block polyether amide resin as a toughening agent, jointly acting with PLA resin, and then adding high-transparency inorganic substance zinc sulfide, the obtained composite material has good tensile toughness and good heat resistance. It is speculated that the possible reason is that, by using block polyether amide resin as a toughening agent, PLA polylactic acid and block polyether amide resin jointly act, and the polyamide segment and polyether segment contained therein can make the polymer chain segment softer, improve the toughness of the polymer, and due to the presence of the polyamide segment, the heat resistance of the polymer is not reduced. Compared with the toughening modification of polylactic acid and petroleum-based high molecular materials, the degradation performance of PLA is affected. Compared with the toughening modification of polylactic acid and acid ester biodegradable high molecular materials, the deformation is large under high temperature conditions, which cannot meet the requirements of a printing substrate.

[0013] However, the applicant further found that, after blending the block polyether amide resin and the PLA resin alone, the improvement effect of toughness is not particularly high, and the reason may be that the compatibility effect of the block polyether amide resin and the PLA resin is poor, a heterogeneous system of "sea-island" structure is formed, and the effect of improving the toughness is not obvious. By introducing ethyl cellulose, the crystallinity of the polymer is changed, the PLA molecular chain is limited to fold and crystallize, and the crystallinity of the system is promoted, so that the mechanical strength is good.

[0014] The second aspect of the present application provides a preparation method of a biodegradable composite material, comprising the following steps:

[0015] S1 drying: polylactic acid, toughening agent, transparent inorganic substance, and cellulose are placed in a vacuum drying box and dried at 70-90 DEG C for 10-15 h to remove water and small molecular residues;

[0016] S2 melt extrusion: the dried polylactic acid, toughening agent, transparent inorganic substance, and cellulose are added into a twin-screw extruder for melt blending according to the weight ratio, the temperature distribution of the feeding section to the die head is 140-165 DEG C, the extruded water-cooled pellet is dried to obtain a granule;

[0017] S3 blown film: The granules are added to the blown film machine for blown film processing to obtain a biodegradable composite material.

[0018] In a preferred embodiment, the screw speed of the twin-screw extruder is 20-30 r / min.

[0019] In a preferred embodiment, the screw speed of the twin-screw extruder is 25 r / min.

[0020] In a preferred embodiment, the thickness of the biodegradable composite film is 13-15 μm.

[0021] A third aspect of the present invention provides an electroplated aluminum film comprising a biodegradable composite material prepared by the above method.

[0022] In a preferred embodiment, the biodegradable composite material is a thin film structure.

[0023] In a preferred embodiment, the structure of the electroplated aluminum film, from bottom to top, includes a biodegradable composite material layer, an electroplated aluminum color layer, a holographic laser layer, an electroplating layer, and an electroplated aluminum adhesive layer, with each layer fixedly connected to the others.

[0024] In a preferred embodiment, the raw materials for preparing the electroplated aluminum color layer include an acrylic resin solution mixture, dye, and leveling agent; the raw materials for preparing the electroplated aluminum adhesive layer include electroplated aluminum adhesive and fumed silica.

[0025] In a preferred embodiment, the raw materials for preparing the electroplated aluminum color layer, by weight, include 5-10 parts of an acrylic resin solution mixture, 0.1-0.5 parts of dye, and 0.01-0.1 parts of leveling agent; the raw materials for preparing the electroplated aluminum adhesive layer include 5-10 parts of electroplated aluminum adhesive and 0.5-5 parts of fumed silica.

[0026] In a preferred embodiment, the raw materials for preparing the electroplated aluminum color layer, by weight, include 7.2 parts of an acrylic resin solution mixture, 0.24 parts of dye, and 0.05 parts of leveling agent; the raw materials for preparing the electroplated aluminum adhesive layer include 8.5 parts of electroplated aluminum adhesive and 1.01 parts of fumed silica.

[0027] A fourth aspect of the present invention provides a method for preparing an electroplated aluminum film, comprising the following steps:

[0028] S1 is a pre-prepared electroplated aluminum color coating and an electroplated aluminum adhesive coating;

[0029] S2 involves coating an electroplated aluminum color layer onto a biodegradable composite material, then heating and curing it in an oven channel to obtain the electroplated aluminum color layer.

[0030] S3 holographically molds a pattern with laser holographic effect on an electroplated aluminum color layer to obtain a holographic laser layer;

[0031] S4 performs vacuum electroplating on the holographic laser layer to obtain the electroplated layer;

[0032] S5 applies an electroplated aluminum adhesive coating to the electroplated layer, and then heats and cures it in an oven channel to obtain an electroplated aluminum film.

[0033] As a preferred embodiment, the preparation method of the electroplated aluminum color layer coating includes the following steps: dissolving the dye in an acrylic resin solution mixture and adding a leveling agent, dispersing for 20-40 minutes, and then filtering with a 300-mesh filter bag to obtain the electroplated aluminum color layer coating.

[0034] As a preferred embodiment, the preparation method of the electroplated aluminum adhesive coating includes the following steps: adding fumed silica to the electroplated aluminum adhesive, dispersing for 40-50 minutes, and then filtering with a 180-mesh filter bag to obtain the electroplated aluminum adhesive coating.

[0035] In a preferred embodiment, the oven channel temperature in step S2 is set to 75℃-95℃-115℃-118℃-158℃-95℃, and the coating speed is 120-130 m / min. Preferably, the coating speed is 128 m / min.

[0036] In a preferred embodiment, the pressure of holographic molding in step S3 is 5-15 kg / m³. 2 The temperature for holographic molding is 160-170℃, and the operating speed for holographic molding is 60-70m / min.

[0037] In a preferred embodiment, the pressure of holographic molding in step S3 is 10 kg / m³. 2 The temperature for holographic molding is 165℃, and the running speed for holographic molding is 65m / min.

[0038] In a preferred embodiment, the vacuum degree of vacuum electroplating in step S4 is 10. -3 ~10 -5 Pa, the aluminum plating speed of vacuum electroplating is 100-120 m / min.

[0039] In a preferred embodiment, the vacuum degree of vacuum electroplating in step S4 is 10. -3 Pa, the aluminum plating speed of vacuum electroplating is 110 m / min.

[0040] In a preferred embodiment, the oven channel temperature in step S5 is set to 90℃-115℃-135℃-135℃-115℃, and the coating speed is 80-100 m / min. Preferably, the coating speed is 90 m / min.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The biodegradable composite material of the present invention uses block polyether amide resin as toughening agent, which works together with PLA resin, and then adds zinc sulfide, an inorganic substance with high transparency. The resulting composite material has good tensile toughness and good heat resistance.

[0043] (2) The biodegradable composite material of the present invention can improve the compatibility of the block polyether amide resin and PLA resin combination by introducing ethyl cellulose, and further promote the crystallinity of the system, thereby having good mechanical strength.

[0044] (3) The biodegradable composite material of the present invention improves the transparency and puncture resistance of the biodegradable composite film by introducing transparent zinc sulfide, and significantly improves the tensile toughness and heat resistance.

[0045] (4) The electroplated aluminum film of the present invention uses a biodegradable composite film as the base film to achieve the degradability of the electroplated aluminum film and reduce environmental problems in the production process.

[0046] (5) The electroplated aluminum film of the present invention is made of biodegradable composite material. While being biodegradable, it has good adhesion, high pattern integrity, and good slitting performance, without affecting the holographic hot stamping performance of the electroplated aluminum film. Attached Figure Description

[0047] Figure 1 This is a flowchart illustrating the production process for preparing the electroplated aluminum film in Example 6 of the present invention. Detailed Implementation

[0048] Example 1

[0049] A biodegradable composite material, the raw materials for which are prepared by weight percentage include 70% polylactic acid, 24.85% toughening agent, 5% transparent inorganic material, and 0.15% cellulose.

[0050] The polylactic acid (PLA) had a melt index of 4 g / 10 min at 190°C and 2.16 kg. It was purchased from Anhui Fengyuan Biotechnology Co., Ltd., and its product name was FY804.

[0051] The toughening agent is a block polyether amide resin, purchased from Arkema, brand name MH2030.

[0052] The transparent inorganic substance is zinc sulfide, purchased from Tianjin Damao Chemical Reagent Factory.

[0053] The cellulose is ethyl cellulose, the mass fraction of ethoxy groups in the ethyl cellulose is 44-47.9%, the viscosity of the ethyl cellulose at 25°C is 3-5.5 mPa·s, and it was purchased from Shanghai Herlist Chemical Co., Ltd., with the grade K4.

[0054] A method for preparing a biodegradable composite material includes the following steps:

[0055] S1 Drying: Place polylactic acid, toughening agent, transparent inorganic material and cellulose in a vacuum drying oven and dry at 80°C for 12 hours to remove moisture and small molecule residues;

[0056] S2 melt extrusion: Dry polylactic acid, toughening agent, transparent inorganic material and cellulose are added to a twin-screw extruder in a weight ratio for melt blending. The temperature distribution from the feed section to the die head is 140-165℃. After extrusion, water cooling, pelleting and drying are performed to obtain granules.

[0057] S3 blown film: The granules are added to the blown film machine for blown film processing to obtain a biodegradable composite material.

[0058] The screw speed of the twin-screw extruder is 25 r / min.

[0059] The thickness of the biodegradable composite film is 14 μm.

[0060] The prepared biodegradable composite material has a thin film structure.

[0061] Comparative Example 1

[0062] A PLA film with a thickness of 15 μm. Purchased from Changding New Materials (Kunshan) Co., Ltd., brand name: PLA biodegradable functional membrane.

[0063] Comparative Example 2

[0064] A PLA blend modified film with a thickness of 15 μm. Purchased from Xiamen Changsu Industrial Co., Ltd., brand name: Baienli ECP standard type.

[0065] Comparative Example 3

[0066] A biaxially oriented PET film with a thickness of 12 μm was purchased from DuPont Hongji Film Co., Ltd. in Foshan, with the grade PET1310.

[0067] Application Examples

[0068] An electroplated aluminum film, the structure of which, from bottom to top, includes the aforementioned thin film, an electroplated aluminum color layer, a holographic laser layer, an electroplated layer, and an electroplated aluminum adhesive layer.

[0069] The raw materials for preparation, by weight, include those shown in Table 1 below:

[0070] Table 1

[0071]

[0072] The acrylic resin solution mixture was purchased from Jiangxi Aotelai New Material Co., Ltd., and its brand name is AT-605.

[0073] The electroplated aluminum adhesive was purchased from Jiangxi Aotelai New Materials Co., Ltd., and its brand name is AT-618.

[0074] The dye was purchased from Wuxi Minghui and its brand name is Solvent Yellow 21.

[0075] The leveling agent was purchased from BYK Chemicals and its brand name is BYK333.

[0076] The fumed silica was purchased from Evonik Germany, and its grade is 622.

[0077] A method for preparing an electroplated aluminum film includes the following steps:

[0078] S1 is a pre-prepared electroplated aluminum color coating and an electroplated aluminum adhesive coating;

[0079] S2 involves coating an electroplated aluminum color layer onto a biodegradable composite film, then heating and curing it in an oven channel to obtain the electroplated aluminum color layer.

[0080] S3 holographically molds a pattern with laser holographic effect on an electroplated aluminum color layer to obtain a holographic laser layer;

[0081] S4 performs vacuum electroplating on the holographic laser layer to obtain the electroplated layer;

[0082] S5 applies an electroplated aluminum adhesive coating to the electroplated layer, and then heats and cures it in an oven channel to obtain an electroplated aluminum film.

[0083] The preparation method of the electroplated aluminum color layer coating includes the following steps: dissolving the dye in an acrylic resin solution mixture and adding a leveling agent, dispersing for 30 minutes and then filtering with a 300-mesh filter bag to obtain the electroplated aluminum color layer coating.

[0084] The preparation method of the electroplated aluminum adhesive coating includes the following steps: adding fumed silica to the electroplated aluminum adhesive, dispersing for 45 minutes, and then filtering with a 180-mesh filter bag to obtain the electroplated aluminum adhesive coating.

[0085] In step S2, the oven channel temperature is set to 75℃-95℃-115℃-118℃-158℃-95℃, and the coating speed is 128m / min.

[0086] The pressure for holographic molding in step S3 is 10 kg / m³. 2 The temperature for holographic molding is 165℃, and the running speed for holographic molding is 65m / min.

[0087] The vacuum degree of vacuum electroplating in step S4 is 10. -3 Pa, the aluminum plating speed of vacuum electroplating is 110 m / min.

[0088] In step S5, the oven channel temperature is set to 90℃-115℃-135℃-135℃-115℃, and the coating speed is 90m / min.

[0089] Performance testing

[0090] 1. Tensile properties: The films of Example 1 and Comparative Examples 1-3 were placed in the fixture of a tensile testing machine, and then a tensile force was applied to stretch the films until they broke.

[0091] 2. Biodegradation rate: The films from Example 1 and Comparative Examples 1-3 were placed in a composting environment with a humidity of 50%-65%, a temperature of 25℃-65℃, maintained oxygen supply, a carbon-to-nitrogen ratio of (25-30):1, and ventilation. The weight change of the samples was analyzed after 8 weeks. Degradation rate = (m0-m) / m0 × 100%; m: sample weight after 8 weeks; m0: sample weight before degradation.

[0092] 3. Light transmittance:

[0093] According to the national standard "GB / T 2410-2008" for the test method of transparency and haze, a transmittance / haze meter (WGT-S) is used. Light emitted from the light source passes through the sample, and the instrument measures the difference between the light transmitted through the material and the light emitted from the light source to determine the transmittance of the sample. Transmittance = (Light transmitted through the material / Light emitted from the light source) × 100%

[0094] The test results are shown in Table 2.

[0095] Table 2

[0096]

[0097] Conclusions: The biodegradable composite film of Example 1 exhibits significantly better tensile properties than pure PLA film and commercially available PLA blend-modified film, but slightly lower than PET film used in traditional electroplated aluminum, thus meeting the tensile strength requirements for use as a base film for holographic electroplated aluminum. The light transmittance of Example 1 is significantly better than pure PLA film and commercially available PLA blend-modified film, but slightly lower than PET film used in traditional electroplated aluminum, thus meeting the light transmittance requirements for use as a base film for holographic electroplated aluminum. The biodegradability of Example 1 is better than commercially available PLA blend-modified film, slightly worse than pure PLA film, but significantly better than PET film used in traditional holographic electroplated aluminum, thus meeting the biodegradability requirements.

[0098] 4. Tensile properties: The electroplated aluminum film of Application Examples 1-8 is placed in the fixture of a tensile testing machine, and then a tensile force is applied to stretch the electroplated aluminum film until it breaks.

[0099] 5. Biodegradation rate: The electroplated aluminum films used in Application Examples 1-8 were placed in a composting environment with humidity of 50%-65%, temperature of 25℃-65℃, oxygen supply, and a carbon-to-nitrogen ratio of (25-30):1 under ventilation. The weight change of the samples was analyzed after 8 weeks. Degradation rate = (m0-m) / m0 × 100%; m: sample weight after 8 weeks; m0: sample weight before degradation.

[0100] 6. Adhesion: After pressing 3M transparent tape onto the side of the sample containing the electroplated aluminum coating, pull the tape apart perpendicular to the sample to completely separate the tape from the sample. Observe whether there is any peeling. Grade 1 is no peeling, Grade 2 is slight porosity, Grade 3 is increased porosity and slight peeling in pieces, and Grade 4 is increased peeling in pieces.

[0101] 7. Pattern integrity: Observe the integrity of the pattern on the sample surface and whether there is discoloration or dullness. If the pattern is intact and there is no discoloration, the brightness level is O; otherwise, it is recorded as X.

[0102] 8. Slicing performance: Observe whether the pattern edge on the sample surface has a serrated edge and whether the edge is clear, and rate it. Grade 1 is no serrated edge and the edge is clear; Grade 2 has a slightly serrated edge; Grade 3 has a moderate serrated edge; Grade 4 has a lot of serrated edges; Grade 5 has obvious serrated edges. The results are shown in Table 3.

[0103] Table 3

[0104]

[0105] Conclusion: The tensile properties of the application example 1 are only 57 MPa, which is far below the standard of ≥100 MPa required for the tensile properties of holographic electroplated aluminum. The pattern integrity is poor and the slitting is poor, so it is unqualified.

[0106] The tensile properties of Application Example 2 are only 88MPa, which is lower than the standard of ≥10MPa required for the tensile properties of holographic electroplated aluminum. The slitting properties are poor, and it is unqualified.

[0107] The key indicators of application example 3, such as tensile properties, biodegradability, adhesion, pattern integrity, and slitting properties, all meet the requirements and are qualified.

[0108] The pattern integrity in Application Example 4 is poor, therefore it is unqualified.

[0109] Application Example 5 has poor slitting properties and is therefore unqualified;

[0110] The key indicators of application example 6, such as tensile properties, biodegradability, adhesion, pattern integrity, and slitting properties, all meet the requirements and are qualified.

[0111] The adhesion of application example 7 is poor, therefore it is unqualified;

[0112] The biodegradation rate of application example 8 was low, which is unacceptable.

Claims

1. An electroplated aluminum film, characterized in that, The structure of the electroplated aluminum film, from bottom to top, includes a biodegradable composite material layer, an electroplated aluminum color layer, a holographic laser layer, an electroplating layer, and an electroplated aluminum adhesive layer; the biodegradable composite material layer, electroplated aluminum color layer, holographic laser layer, electroplating layer, and electroplated aluminum adhesive layer are all fixedly connected to each other. The biodegradable composite material is prepared by means of the following raw materials by weight percentage: 60-78% polylactic acid, 20-30% toughening agent, 1-10% transparent inorganic material, and 0.1-0.5% cellulose. The polylactic acid has a melt index of 1-6 g / 10 min at 190°C and 2.16 kg. The toughening agent is a block polyether amide resin; The transparent inorganic substance is zinc sulfide.

2. The electroplated aluminum film according to claim 1, characterized in that, The cellulose is ethyl cellulose, and the mass fraction of ethoxy groups in the ethyl cellulose is 44-47.9%.

3. The electroplated aluminum film according to claim 2, characterized in that, The viscosity of the ethyl cellulose at 25°C is 3-5.5 mPa·s.

4. The electroplated aluminum film according to claim 1, characterized in that, The method for preparing the biodegradable composite material includes the following steps: S1 Drying: Place polylactic acid, toughening agent, transparent inorganic material and cellulose in a vacuum drying oven and dry at 70-90℃ for 10-15 hours to remove moisture and small molecule residues. S2 melt extrusion: Dry polylactic acid, toughening agent, transparent inorganic material and cellulose are added to a twin-screw extruder in a weight ratio for melt blending. The temperature distribution from the feed section to the die head is 140-165℃. After extrusion, water cooling, pelleting and drying are performed to obtain granules. S3 blown film: The granules are added to the blown film machine for blown film processing to obtain a biodegradable composite material.

5. A method for preparing the electroplated aluminum film according to claim 1, characterized in that, Includes the following steps: S1 is a pre-prepared electroplated aluminum color coating and an electroplated aluminum adhesive coating; S2 involves coating an electroplated aluminum color layer onto a biodegradable composite material, then heating and curing it in an oven channel to obtain the electroplated aluminum color layer. S3 holographically molds a pattern with laser holographic effect on an electroplated aluminum color layer to obtain a holographic laser layer; S4 performs vacuum electroplating on the holographic laser layer to obtain the electroplated layer; S5 applies an electroplated aluminum adhesive coating to the electroplated layer, and then heats and cures it in an oven channel to obtain an electroplated aluminum film.

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