Antifogging high-barrier BOPET film and manufacturing method thereof
阅读说明：本技术 防雾的高阻隔bopet薄膜及其制造方法 (Antifogging high-barrier BOPET film and manufacturing method thereof ) 是由 李朝辉 黎坛 王俊峰 于 2021-09-13 设计创作，主要内容包括：本申请涉及包装技术领域,本发明公开了一种防雾的高阻隔BOPET薄膜及其制造方法,该高阻隔BOPET薄膜包括：依次设置的PVDC涂层、聚氨酯底胶层、BOPET基材层、耐液性丙烯酸涂层和防雾剂涂层；所述BOPET基材层的厚度为15-30μm；所述耐液性丙烯酸涂层和防雾剂涂层的厚度比为(0.5-1.5)μm：(0.2-0.5)μm。本发明提供的高阻隔BOPET薄膜能达到与PET盒子具有良好的热封强度且封口易揭,具有良好的阻隔氧气、阻隔水分的特点,透明度高及冷防雾效果好,便于生鲜果蔬包装产品的贮存及运输,用于PET盒子封口符合环保要求的同一材质回收利用。此外,本发明制造方法简单易行。(The invention relates to the technical field of packaging, and discloses an antifogging high-barrier BOPET film and a manufacturing method thereof, wherein the high-barrier BOPET film comprises the following components in parts by weight: the liquid-resistant acrylic coating comprises a PVDC coating layer, a polyurethane primer layer, a BOPET substrate layer, a liquid-resistant acrylic coating layer and an antifogging agent coating layer which are sequentially arranged; the thickness of the BOPET substrate layer is 15-30 μm; the thickness ratio of the liquid-resistant acrylic coating to the antifogging agent coating is (0.5-1.5) mu m: (0.2-0.5) μm. The high-barrier BOPET film provided by the invention has good heat-seal strength with a PET box, is easy to tear open, has the characteristics of good oxygen and moisture barrier, is high in transparency and good in cold anti-fog effect, is convenient for storage and transportation of fresh fruit and vegetable packaging products, and is used for recycling the same material of the PET box seal which meets the environmental protection requirement. In addition, the manufacturing method is simple and easy.)
1. An anti-fog high-barrier BOPET film, comprising:
the liquid-resistant acrylic coating comprises a PVDC coating layer, a polyurethane primer layer, a BOPET substrate layer, a liquid-resistant acrylic coating layer and an antifogging agent coating layer which are sequentially arranged;
the thickness of the BOPET substrate layer is 15-30 μm; the thickness ratio of the liquid-resistant acrylic coating to the antifogging agent coating is (0.5-1.5) mu m: (0.2-0.5) μm.
2. The high barrier BOPET film of claim 1, wherein the material forming the PVDC coating comprises: vinylidene chloride monomer and organosilicon modified diphenol propane epoxy resin; the mass ratio of the vinylidene chloride monomer to the organosilicon modified diphenol propane epoxy resin is (35-40): (10-15).
3. The high barrier BOPET film of claim 2, wherein the material forming the polyurethane primer layer comprises: diisocyanate compounds, polyethylene glycol and organic silicon modified diphenol propane epoxy resin.
4. The high barrier BOPET film of claim 2, wherein the material forming the liquid-resistant acrylic coating comprises the following components in mass content:
5. the method for manufacturing a high barrier BOPET film according to any one of claims 1 to 4, comprising the steps of:
taking a BOPET optical film with the thickness of 15-30 mu m as a base material;
coating a liquid-resistant acrylic coating and an antifogging agent coating on one surface of the substrate in sequence, and controlling the thickness ratio of the formed liquid-resistant acrylic coating to the antifogging agent coating to be (0.5-1.5) mu m: (0.2-0.5) μm; and sequentially coating the polyurethane primer coating and the PVDC emulsion on the other surface of the base material to obtain the antifogging high-barrier BOPET film.
6. The manufacturing method of claim 5, wherein the polyurethane primer coating comprises the following components in percentage by mass:
7. the method according to claim 6, wherein the amount of the polyurethane primer coating is controlled to be 0.5 to 1.2g/m2(ii) a The drying temperature range for forming the polyurethane primer layer is preferably 85-120 ℃.
8. The manufacturing method according to claim 5, wherein the PVDC emulsion is mainly prepared from the following components in parts by weight:
9. the method according to claim 8, wherein the coating amount of the PVDC emulsion is controlled to be 2.5 to 3.5g/m2The coating speed is preferably 150 to 300 m/min.
10. The method according to claim 9, wherein the PVDC emulsion is applied and then dried by multi-stage drying to form the PVDC coating, and the first stage of the multi-stage drying has an infrared temperature of 110 to 130 ℃ for 2 to 5 seconds.
Technical Field
The application belongs to the technical field of packaging, and particularly relates to an anti-fog high-barrier BOPET film and a manufacturing method thereof.
Background
Polyethylene terephthalate (PET) plastics have good formability, optical property, weather resistance and the like, and the film sheet thereof can be used as a packaging material of various foods, medicines and the like. Wherein, be used for giving birth to bright food package box at present and adopt food level PET material to make usually, traditional package sealing mode is: the covering and sealing are realized by laminating a film on the surface of the base material or thermally sealing the base material and the PET box after compounding.
However, the existing film coating method has some disadvantages, one of which is: when the film is uncovered, the heat sealing is too large, and the sealing and the film uncovering are difficult; the second step is as follows: the laminated paper base material is more common, has poor transparency and even is completely opaque, and is not beneficial to application. In addition, the compounding method is generally that a polypropylene (PP) film base material is cast and compounded with a CPP film layer or a Polyethylene (PE) film layer and the like; disadvantages of this composite heat-sealable film include: the transparency is poor, and after the PET packaging box is used, the PET packaging box does not meet the requirement of environmental protection on recycling the same material.
Therefore, a technology which is more conveniently applied to the sealing package of the fresh packaging box and can replace the existing film spraying and composite film covering modes is urgently needed in the market.
Disclosure of Invention
In view of the above, the invention provides an antifogging high-barrier BOPET film and a manufacturing method thereof, the high-barrier BOPET film provided by the invention can achieve the advantages of good heat-seal strength with a PET box, easy seal uncovering, good oxygen and moisture barrier characteristics, high transparency, good cold antifogging effect, convenience for storage and transportation of fresh fruit and vegetable packaging products, and recycling of the same material for sealing the PET box, which meets the environmental protection requirement.
The invention provides an antifogging high-barrier BOPET film, which comprises: the liquid-resistant acrylic coating comprises a PVDC coating layer, a polyurethane primer layer, a BOPET substrate layer, a liquid-resistant acrylic coating layer and an antifogging agent coating layer which are sequentially arranged;
the thickness of the BOPET substrate layer is 15-30 μm; the thickness ratio of the liquid-resistant acrylic coating to the antifogging agent coating is (0.5-1.5) mu m: (0.2-0.5) μm.
In a preferred embodiment of the invention, the material forming the PVDC coating comprises: vinylidene chloride monomer and organosilicon modified diphenol propane epoxy resin; the mass ratio of the vinylidene chloride monomer to the organosilicon modified diphenol propane epoxy resin is (35-40): (10-15).
In a preferred embodiment of the present invention, the material forming the polyurethane primer layer comprises: diisocyanate compounds, polyethylene glycol and organic silicon modified diphenol propane epoxy resin.
In a preferred embodiment of the invention, the material forming the liquid-proof acrylic coating comprises the following components in percentage by mass:
the embodiment of the invention provides a method for manufacturing a high-barrier BOPET film, which comprises the following steps:
taking a BOPET optical film with the thickness of 15-30 mu m as a base material;
coating a liquid-resistant acrylic coating and an antifogging agent coating on one surface of the substrate in sequence, and controlling the thickness ratio of the formed liquid-resistant acrylic coating to the antifogging agent coating to be (0.5-1.5) mu m: (0.2-0.5) μm; and sequentially coating the polyurethane primer coating and the PVDC emulsion on the other surface of the base material to obtain the antifogging high-barrier BOPET film.
In a preferred embodiment of the invention, the polyurethane primer coating comprises the following components in percentage by mass:
in a preferred embodiment of the invention, the coating weight of the polyurethane primer coating is controlled to be 0.5-1.2 g/m2(ii) a The drying temperature range for forming the polyurethane primer layer is preferably 85-120 ℃.
In a preferred embodiment of the present invention, the PVDC emulsion is mainly prepared from the following components in parts by weight:
in a preferred embodiment of the invention, the coating weight of the PVDC emulsion is controlled to be 2.5-3.5 g/m2The coating speed is preferably 150 to 300 m/min.
In a preferred embodiment of the invention, after the PVDC emulsion is coated, a PVDC coating is formed in a multi-stage drying manner, wherein the infrared temperature of the first stage in the multi-stage drying is 110-130 ℃ and the time is 2-5 seconds.
The invention provides a high-barrier BOPET film for sealing a PET box, which has a five-layer structure and sequentially comprises a PVDC coating, a polyurethane primer layer, a BOPET substrate layer, a liquid-resistant acrylic coating and an antifogging agent coating. Wherein the thickness of the BOPET substrate layer is 15-30 μm; the thickness ratio of the liquid-resistant acrylic coating to the antifogging agent coating is (0.5-1.5) mu m: (0.2-0.5) μm. According to the invention, one surface of the BOPET film is coated with the liquid-resistant acrylic coating with a certain thickness, then the antifogging agent coating is coated, and the other surface of the BOPET film is mainly coated with the PVDC coating to prepare the high-barrier coating film, so that the high-barrier coating film has good heat-sealing strength with a PET box, an antifogging effect and high transparency, and can achieve an effect of easy uncovering; meanwhile, the coating has good fresh-keeping and fragrance-keeping functions due to the excellent barrier effect. In addition, the base material of the film is PET, and the applied box material is also PET, so that the same material meeting the environmental protection requirement is recycled.
The BOPET heat-sealing antifogging cover film is prepared by a coating mode, the process is simple, the cost performance is high, great convenience and good customer experience are brought to the use of the packaging box, and the market and potential market capacity are huge.
Drawings
Fig. 1 is a schematic structural diagram of an anti-fog high-barrier BOPET film in the embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The application provides antifog high resistant BOPET film, include: the liquid-resistant acrylic coating comprises a PVDC coating layer, a polyurethane primer layer, a BOPET substrate layer, a liquid-resistant acrylic coating layer and an antifogging agent coating layer which are sequentially arranged;
the thickness of the BOPET substrate layer is 15-30 μm; the thickness ratio of the liquid-resistant acrylic coating to the antifogging agent coating is (0.5-1.5) mu m: (0.2-0.5) μm.
The high-barrier BOPET film provided by the invention has good heat-seal strength with a PET box, is easy to tear open, has the characteristics of good oxygen and moisture barrier, is high in transparency and good in cold anti-fog effect, is convenient for storage and transportation of fresh fruit and vegetable packaging products, and is also beneficial to environmental protection.
Referring to fig. 1, fig. 1 is a schematic structural diagram of an anti-fog high-barrier BOPET film in the embodiment of the present application, where 1 is a PVDC coating; 2 is a polyurethane primer layer; 3 is a BOPET substrate layer; 4 is a liquid-resistant acrylic coating; and 5, an antifogging agent coating.
One side of the high-barrier BOPET film provided by the embodiment of the invention is provided with a PVDC coating layer 1 which is formed by coating on a polyurethane primer layer 2, the other side of the BOPET substrate layer 3 is provided with a liquid-resistant acrylic coating 4 and an antifogging agent coating 5, and the specific structure is shown in figure 1.
In the coating film of the embodiment of the invention, the BOPET substrate layer 3 is a biaxially oriented polyethylene terephthalate (PET) film substrate, and the thickness is 15-30 μm, preferably 20-28 μm, and more preferably 25 μm. The base material of the film is PET, and the applied box material is also PET, so that the same material meeting the environmental protection requirement is recycled.
In the embodiment of the invention, waterborne polyurethane is firstly coated on one surface of a BOPET substrate and dried to form a primer coating 2, and then PVDC (polyvinylidene chloride) coating with high barrier property is coated on the primer coating to form a film of the PVDC coating 1. The PVDC coating has excellent oxygen and moisture blocking functions and excellent fresh-keeping functions.
In a specific embodiment of the invention, the material forming the PVDC coating (PVDC emulsion) essentially comprises: vinylidene chloride monomer (VDC) and organosilicon modified diphenol propane epoxy resin are coated and reacted in the presence of initiator, emulsifier, assistant and other material components, and the PVDC coating is formed after drying. Wherein the mass ratio of the vinylidene chloride monomer to the organosilicon-modified diphenol propane epoxy resin is preferably (35-40): (10-15).
In a preferred embodiment of the present invention, the PVDC emulsion is mainly prepared from the following components in parts by weight:
specifically, soft water is generally adopted to prepare the emulsion, and the mass content is preferably 40%; the organic silicon modified diphenol propane type epoxy resin and the polysiloxane cross-linking agent have a cross-linking effect to form a stable cross-linked network structure, so that the oxygen resistance, wear resistance, water resistance and the like of the coating are improved, and particularly, commercially available general materials can be adopted. The emulsifier used is preferably a mixed emulsifier of sodium secondary alkane sulfonate and a nonionic surfactant; the initiator is preferably a sodium persulfate initiator. In addition to the cross-linking agent and release agent, the present invention may also include auxiliary agents such as commercially available defoamers, pH adjusters, etc., such as CK-1504 polyether defoamer available from Tianjin Gaita New Material science and technology, Inc., dimethylethanolamine pH adjuster, and palm wax lubricant model ML-180.
Further preferably, the PVDC emulsion of the embodiment of the present invention is prepared from the following raw materials in parts by weight:
and the material for forming the polyurethane primer layer is preferably water-based polyurethane primer, which mainly comprises: water, diisocyanate compounds, polyethylene glycol and organosilicon modified diphenol propane epoxy resin. In a preferred embodiment of the invention, the polyurethane primer coating comprises the following components in percentage by mass:
the organic silicon modified diphenol propane epoxy resin mainly plays a role in crosslinking, and the specific specification and model of the epoxy resin are not particularly limited. The chain extender is preferably ethylene diamine ethyl sodium sulfonate chain extender, and the pH regulator is preferably dimethyl ethanolamine.
On the other side of the BOPET substrate, the liquid-resistant acrylic coating is coated to form a liquid-resistant acrylic coating 4, and then an antifogging agent coating 5 is coated. The acrylic coating is a coating film layer formed by coating, drying and curing the acrylic emulsion, and has liquid resistance. In the present invention, the thickness ratio of the liquid-resistant acrylic coating layer to the antifogging agent coating layer is (0.5-1.5) μm: (0.2-0.5) μm; according to the invention, the BOPET film is coated with the liquid-resistant acrylic coating and then coated with the antifogging agent to form the blocking and antifogging PET film, so that the problems of the PET box sealing cover manufactured by a film coating mode (for example, the film coating is thicker, generally 20-70 microns, uneven in thickness, large in heat-sealing strength fluctuation and poor in transparency) can be solved to a certain extent.
In a specific embodiment of the present invention, the material forming the liquid-proof acrylic coating mainly includes: water, ethylene-acrylic acid copolymer, amino resin and oxazoline group crosslinking agent; reacting and coating the mixture into a film in the presence of an emulsifier, an initiator, a silane coupling agent and other auxiliary agents. On one hand, the oxazoline group cross-linking agent and carboxyl in acrylic resin carry out chemical cross-linking reaction under the action of high temperature, so that the acrylic coating forms a compact network structure, and meanwhile, the oxazoline group cross-linking agent consumes the carboxyl of acrylic acid, thereby avoiding the problem of water absorption and expansion of the carboxyl and effectively solving the problem of water resistance of the PET coating film. On the other hand, the silane coupling agent promotes the silanol bond generated by the acrylic monomer in the polymerization reaction to play a crosslinking role, so that the network structure of the acrylic coating is more compact, the cohesive force of the coating is enhanced, the erosion damage of liquid to the coating is reduced, and the liquid resistance of the acrylic coating is improved.
Specifically, the liquid-resistant acrylic coating is prepared from the following raw materials in parts by weight:
the acrylic emulsion comprises soft water; the mass content of the soft water is preferably 55% to 65%, more preferably 55%.
The acrylic emulsion comprises an ethylene-acrylic acid copolymer; the ethylene-acrylic acid copolymer is preferably contained in an amount of 12 to 16% by mass, more preferably 13% by mass.
The acrylic emulsion comprises amino resin; in the invention, the amino resin is preferably AA-9077 aqueous amino resin. The mass content of the amino resin is preferably 6% to 9%, more preferably 8%.
The acrylic emulsion comprises a silane coupling agent; the silane coupling agent is preferably an LT-5603 epoxy silane coupling agent. In the present invention, the silane coupling agent is preferably contained in an amount of 4.5 to 5.5% by mass, more preferably 5% by mass. The acrylic emulsion comprises oxazoline group cross-linking agents; preferably, the oxazoline-based crosslinking agent is selected from WS-500 of Han Lai of Shanghai. The mass content of the oxazoline-based crosslinking agent is preferably 2.0% to 4.0%, more preferably 3%.
The acrylic emulsion comprises a mixed emulsifier of secondary alkane sodium sulfonate and a nonionic surfactant, and the mass content of the mixed emulsifier is preferably 2.5-4%, and more preferably 3.0%. Wherein the mass ratio of the secondary alkane sulfonic acid sodium to the nonionic surfactant is preferably 2: 1.
The acrylic emulsion comprises a sodium persulfate initiator; the mass content of the sodium persulfate initiator is preferably 0.3 to 1.0%, and more preferably 0.8%.
The acrylic emulsion comprises a polyether defoamer; the mass content of the polyether defoamer is preferably 0.3-0.5%. The acrylic emulsion comprises a multifunctional amine pH regulator; the mass content of the multifunctional amine pH regulator is preferably 0.5-1%, and more preferably 0.5%. The acrylic emulsion comprises a silica release agent; the mass content of the silica separant is preferably 0.2 to 0.5%, and more preferably 0.25%.
The acrylic emulsion includes a palm wax; the mass content of the palm wax is preferably 0.5-1.5%, and an ML-180 lubricant can be specifically adopted.
The total amount of the components satisfies 100%. In the present invention, the thickness of the liquid-proof acrylic coating layer is preferably 0.5 to 1.5 μm, and more preferably 1.5 μm. In the invention, the acrylic coating is arranged on the surface of one side of the PET base layer in a coating mode, and can be contacted and thermally sealed with a food packaging box made of PET materials after being dried and cured. The acrylic emulsion prepared from the components is coated on the PET base layer film, so that the PET base layer film has strong PET film adsorption performance, has excellent heat sealing strength with a PET sheet, and greatly improves the heat sealing performance of the PET coating film. The acrylic acid coating has an excellent smell blocking function, ensures that fresh fruits contained in the coating can not taint smell mutually when being stored together, and is further beneficial to application.
In the antifogging high-barrier BOPET film provided by the embodiment of the invention, the antifogging agent coating 5 with a certain thickness is arranged on the surface of the liquid-resistant acrylic coating 4. The antifogging agent coating can be formed by coating antifogging agent emulsion and drying and curing at high temperature; the antifogging agent emulsion with specific components is coated on the surface of the liquid-resistant acrylic coating, and the antifogging agent emulsion has a good cold antifogging effect. The invention has good cold antifogging effect, can achieve the effect that the film surface is completely free from water mist and water drop condensation, solves the problem that the packaged vegetables and fruits and fresh fruits are put into a freezer to be refrigerated, and the quick cold and hot temperature difference causes the fogging phenomenon of the packaging box, so that consumers can easily see the physical state in the packaging box when purchasing, and the purchasing desire of the consumers is enhanced.
The antifogging agent coating layer is prepared from the following raw materials in percentage by mass:
preferably, the antifogging agent coating (referred to as antifogging layer) is formed by coating and drying the antifogging agent emulsion. The antifogging agent emulsion comprises acrylic acid graft modified polyester polyol; the specific type of the product sold in the market is adopted. The mass content of the acrylic acid graft modified polyester polyol is preferably 8-11%, and more preferably 10%. The antifogging agent emulsion comprises hexamethylene diisocyanate; the mass content of the hexamethylene diisocyanate is preferably 2.1-3.5%, and more preferably 3%. The components of the antifogging agent emulsion have the functions of adhesion and bonding, and have the function of crosslinking with an acrylic coating of the primer.
The antifogging agent emulsion comprises acetone which is used as a solvent to dissolve other solid raw materials in the formula; the mass content of the acetone is preferably 2.5-5.5%, and more preferably 3.5%. The antifogging agent emulsion comprises dimethylolpropionic acid; the mass content of the dimethylolpropionic acid is preferably 3.5-4.5%, and more preferably 4%. The antifogging agent emulsion comprises 3-allyloxy-2-hydroxy-1-propane sulfonic acid sodium salt; the mass content of the 3-allyloxy-2-hydroxy-1-propanesulfonic acid sodium salt is preferably 1.5-3.5%, and more preferably 3.0%. The antifogging agent emulsion comprises isopropyl alcohol; the content of isopropyl alcohol is preferably 2.5% to 3.5% by mass, and more preferably 3.0% by mass. The antifogging agent emulsion comprises ethylene glycol; the mass content of the ethylene glycol is preferably 2.2-3%, and more preferably 3.0%.
Wherein the mass content of the initiator is preferably 0.3-1.2%, and more preferably 0.5%; it is preferred to use a pivaloyl peroxypivalate initiator. The mass content of the catalyst is preferably 0.5-1.5%, and more preferably 1.0%; for example, a triethylenediamine catalyst.
In addition, the antifogging emulsion comprises defoamers, such as polyethers. The mass content of the defoaming agent is preferably 0.2-0.8%, and more preferably 0.5%. The antifogging agent comprises a palm wax antiblocking agent; the mass content of the palm wax anti-sticking agent is preferably 1.5-2.5%, and more preferably 2.5%. The antifogging agent comprises an anti-sticking agent SiO2(ii) a The anti-sticking agent SiO2The content of (b) is preferably 0.2 to 0.8% by mass, more preferably 0.5% by mass. The antifogging agent comprises soft water; the mass content of the soft water is preferably 65-75%, and more preferably 75%. In the invention, the total amount of the components meets 100 percent.
The traditional development direction may be to add an antifogging agent into the coating, and the direction can cause that the amount of the antifogging agent added is extremely large, the heat sealing effect is seriously influenced, and the antifogging effect is poor and cannot meet the requirement. As is known, the antifogging agent industry has not yet appeared a variety of antifogging agents which can be added into the coating to achieve a good cold antifogging effect. According to the invention, the acrylic coating is formed by coating the liquid-resistant acrylic emulsion, and a relatively thin antifogging agent layer is coated on the surface of the acrylic resin layer, so that a relatively good cold antifogging effect can be achieved; in the invention, the thickness of the antifogging agent coating is 0.2-0.5 μm, and more preferably 0.5 μm.
The embodiment of the invention provides a method for manufacturing a high-barrier BOPET film, which comprises the following steps:
taking a BOPET optical film with the thickness of 15-30 mu m as a base material;
coating a liquid-resistant acrylic coating and an antifogging agent coating on one surface of the substrate in sequence, and controlling the thickness ratio of the formed liquid-resistant acrylic coating to the antifogging agent coating to be (0.5-1.5) mu m: (0.2-0.5) μm; and sequentially coating the polyurethane primer coating and the PVDC emulsion on the other surface of the base material to obtain the antifogging high-barrier BOPET film.
The manufacturing of the antifogging high-barrier BOPET film provided by the embodiment of the invention is completed by the following steps:
(1) unwinding: under the tension of 50-120N, a BOPET (biaxially oriented polyethylene terephthalate) optical film roll (the thickness is 15-30 mu m) is unfolded, the film roll continuously moves forwards through a plurality of guide rollers, two same stations are adopted to work alternately, and the purposes of continuously unreeling and changing the roll are achieved by automatic splicing and quick film changing.
(2) Acrylic acid coating step: the liquid-resistant acrylic coating is coated on the corona surface of the BOPET optical film in a kiss coating roller reverse rotation mode (coating is firstly corona to improve the adhesive force), and the coating amount can be 2.0-4.0 g/m2The speed is 150 to 350 m/min.
(3) Acrylic acid drying process: in the drying process, the film needs to have certain tension control, and the principle of the tension size is as follows: the film can be straightened and leveled, and the control is as follows: 40-120N, the oven is divided into several sections, the oven temperature and the time of drying of each section are all different, and the infrared temperature of first section is: 110-130 ℃, time: 1.0-2.0 seconds, the temperature range of several sections of the electric heating oven is 110-120 ℃, and the time is as follows: 10-15 seconds.
(4) Coating the antifogging agent: the preferred antifogging agent emulsion is coated on the liquid-resistant acrylic coating by a reverse roll kiss coating roll, and the coating amount for forming the antifogging agent coating can be 0.5-0.8 g/m2The speed is 150 to 350 m/min.
(5) And (3) drying the antifogging agent: in the drying process, the film needs to have certain tension control, and the principle of the tension size is as follows: the film can be straightened and leveled, and the control is as follows: 40-120N, the oven is divided into several sections, the temperature and the time of drying of the oven of each section are all different, and the infrared temperature of the first section is: 110-130 ℃, time: 2.0 to 5.0 seconds. The temperature range of several sections of the electric heating oven is 110-120 ℃, and the time is as follows: 8-12 seconds.
(6) A corona treatment process: and (3) passing the film corona electrode under the power of 3.0-10 KW, and uniformly treating the surface of the film with the surface tension of more than 38 dyne on the non-corona surface of the film.
(7) A primary coating process: coating the preferable waterborne polyurethane primer coating on the BOPET film subjected to corona treatment by a coating roll reverse roll kiss type, wherein the coating amount can be controlled to be 0.5-1.2 g/m2The speed is 150 to 500 m/min.
(8) And (3) primary coating drying: in the drying process, the film needs to have certain tension control, and the principle of the tension size is as follows: the film can be straightened and leveled, and the control is as follows: 50-100N, the oven is divided into a plurality of sections, the temperature and the drying time of each section are different, the temperature range of the plurality of sections of the electric heating oven is 85-120 ℃, and the time is as follows: 8-12 seconds.
(9) A top coating process: coating PVDC emulsion on the polyurethane primer coating layer in a reverse roll kiss mode through a coating roll, wherein the coating weight of the general top coating layer is 2.5-3.5 g/m2The speed is 150 to 300 m/min.
(10) A top coating and drying process: in the drying process, the film needs to have certain tension control, and the principle of the tension size is as follows: the film can be straightened and leveled, and the control is as follows: 55-90N, the oven is divided into a plurality of sections, the temperature and the drying time of the oven in each section are different, and the infrared temperature in the first section is as follows: 110-130 ℃, time: 2-5 seconds, the electric heating oven is divided into 3-5 sections, the temperature is gradually decreased, the temperature range is 90-120 ℃, and the total drying time of the top coating is as follows: 10-20 seconds. The thickness of the bottom coating is 1.0-2.0 μm; the thickness of the top coating is 0.2 to 0.5 μm.
(11) An online detection process: the method comprises the steps of adopting the working principle of on-line image scanning of a camera, irradiating the surface of a product by adopting a light source when the production line is in high-speed production, simultaneously scanning and collecting the image of the product irradiated by the light source in real time through the camera, processing and dividing the collected image, and recording marks, wherein the camera is a CCD (charge coupled device) industrial camera, and the light source is a high-brightness LED (light emitting diode) linear light condensing source and is used for judging the quality and the drying condition of the product.
(12) A winding process: the coated product needs to be rolled, the rolling tension and the pressure of a compression roller need to be controlled during rolling, the process that the rolling tension and the pressure are reduced from small to large has an optimal attenuation rate, the process needs to be finely set according to a base material film, coating amount, film width, film thickness and the like, the rolling tension can be 50-110N, and the pressure of the compression roller is 3.0 +/-2 kg.
The antifogging high-barrier BOPET film prepared by the embodiment of the invention has a structure comprising a PVDC coating, a polyurethane primer layer, a BOPET substrate layer, a liquid-resistant acrylic coating and an antifogging agent coating which are sequentially arranged. Wherein the thickness of the BOPET substrate layer is 15-30 μm; the thickness ratio of the liquid-resistant acrylic coating to the antifogging agent coating is (0.5-1.5) mu m: (0.2-0.5) μm. The film coating structure mode is innovative, and the BOPET coating film with the functions of fog prevention, heat sealing, easy uncovering, fragrance preservation and fresh keeping is formed by the double-side coating method.
In the embodiment of the invention, the coating film has the following remarkable advantages; firstly, the method comprises the following steps: the heat sealing strength is moderate; under the heat sealing condition of 160 ℃ 0.14MPa 1S, the heat sealing strength of the BOPET coating film and the PET box is more than or equal to 4.5N/15mm, for example, 4.5-6.5N/15 mm, and the heat sealing strength within the range can not only ensure the sealing capability of the box cover, but also ensure that the box cover can be easily opened when the cover is opened, thereby achieving the effect of easy cover uncovering. II, secondly: excellent barrier effect (high barrier performance, oxygen permeability less than or equal to 10 cc/m)2Day, water permeability less than or equal to 4g/m2Day); the liquid-resistant acrylic coating and the PVDC coating are combined with excellent oxygen and moisture barrier functions, so that the preservative film has excellent preservation and fragrance keeping functions, convenience is provided for packaging and transporting packaged fresh fruits and vegetables to a sales shelf, and special refrigeration, preservation and storage are not needed in the process. Meanwhile, the environment can be provided for instant fruits, or the possibility is provided for packaging and selling of the instant fruits or cakes and the like, namely, the fruits can be packaged after being cleaned and cut into pieces and can be directly placed and sold. Thirdly, the method comprises the following steps: the transparency is high; the haze may be: 6.5, the glossiness is: 88.4 percent. Fourthly, the method comprises the following steps: the antifogging effect is good, and the fogging phenomenon does not occur in cold and hot environments. Fifthly: the PET box seal material is used for recycling the same material meeting the environmental protection requirement. Sixthly, the preparation process is simple, the efficiency is high, and the cost performance is high.
In order to better understand the technical content of the invention, specific examples are provided below to further illustrate the invention.
Example 1
The manufacturing of the antifogging high-barrier BOPET film provided by the embodiment of the invention is completed by the following steps:
(1) unwinding: a BOPET optical film roll with the thickness of 25 mu m is unfolded under the tension of 100N, the film roll continuously moves forwards through a plurality of guide rollers, two same stations are adopted to work alternately, and automatic splicing and rapid film changing are adopted to continuously unreel and change rolls.
(2) A corona treatment process: the corona electrode of the film passes through the corona electrode under the power of 8.0KW, and the surface of the film with the surface tension of 50 dyne value is uniformly processed on the non-corona surface of the film.
(3) Acrylic acid coating step: coating the liquid-resistant acrylic coating on the corona surface of the BOPET optical film by a reverse roll kiss coating method, wherein the coating amount can be 2.2g/m2The speed was 200 m/min.
The mass ratio of the acrylic coating is as follows:
(4) acrylic acid drying process: in the drying process, the tension is controlled as follows: 110N, the oven is divided into a plurality of sections, and the infrared temperature of the first section is as follows: 130 ℃, time: 2.0 seconds, 3 sections of electric oven, the first section is 120 ℃, time: 5 seconds; second stage 115 ℃, time: 5 seconds; the third stage was 110 ℃, time: for 5 seconds.
(5) Coating the antifogging agent: the antifogging agent emulsion is coated on the liquid-resistant acrylic coating by a reverse roll kiss coating roll, and the coating amount for forming the antifogging agent coating can be 0.5g/m2The speed was 200 m/min.
The antifogging agent comprises the following components in percentage by mass:
(6) and (3) drying the antifogging agent: in the drying process, the tension is controlled as follows: 90N, the oven is divided into 4 sections, and the infrared temperature of the 1 st section is: 130 ℃, time: for 2 seconds. The back 3 stages are electric heating ovens, the temperature is 120 ℃, and the time is as follows: 5S; second stage temperature 115 ℃, time: 5S; the third stage was 110 ℃, time: for 5 seconds.
(7) A primary coating process: coating the aqueous polyurethane primer coating on the corona surface of the BOPET film by a reverse roll kiss type coating roll, and controlling the coating amount to be 1.2g/m by the mesh number and the speed of the coating roll2The number of the coating roller is 220 meshes, the speed of the coating roller is 220m/min, and the coating speed is 200 m/min.
The polyurethane primer coating comprises the following components in percentage by mass:
(8) and (3) primary coating drying: in the drying process, the tension is controlled as follows: 100N, the oven is an electric heating oven with 3 sections, the temperature of the 1 st section is as follows: at 120 ℃, for 3S; the temperature of the 2 nd section is 115 ℃, and the time is 3S; temperature at stage 3: 110 ℃, time: for 4 seconds.
(9) A top coating process: adopting a 120-mesh ceramic coating roller, coating PVDC emulsion on the polyurethane primer coating layer in a kiss mode at a reverse speed of 220m/min, and controlling the coating weight of the coating layer to be 3.5g/m2The coating speed was 200 m/min.
The PVDC emulsion is prepared from the following raw materials in parts by weight:
(10) a top coating and drying process: in the drying process, the tension is controlled as follows: 90N, the oven is divided into 4 sections, and the infrared temperature of the 1 st section is: 130 ℃, time: 3 seconds, the later 3 sections are electric heating ovens, the temperature is set progressively decreasing, the first section is 120 ℃, the time is as follows: 3S; stage 2 was 115 ℃ for the following times: 3S; stage 3 was 110 ℃, time: for 3 seconds.
(11) The subsequent process comprises the following steps: winding, detecting, rewinding and curing.
Example 2
The manufacturing of the antifogging high-barrier BOPET film provided by the embodiment of the invention is completed by the following steps:
(1) unwinding: the method comprises the following steps of unfolding a 25 mu m BOPET optical film roll under the tension of 110N, enabling the film roll to continuously move forwards through a plurality of guide rollers, adopting two same stations to alternately work, automatically splicing and quickly changing the film, and continuously unreeling and changing the roll.
(2) A corona treatment process: the corona electrode of the film passes through the corona electrode under the power of 8.0KW, and the surface of the film with the surface tension of 50 dyne value is uniformly processed on the non-corona surface of the film.
(3) Acrylic acid coating step: the liquid-resistant acrylic coating is coated on the corona surface of the BOPET optical film by a reverse roll kiss coating roll, and the coating amount can be 3.5g/m2The speed was 200 m/min.
The mass ratio of the acrylic coating is as follows:
(4) acrylic acid drying process: in the drying process, the tension is controlled as follows: 110N, the oven is divided into a plurality of sections, and the infrared temperature of the first section is as follows: 130 ℃, time: 2.0 seconds, the electric heating oven is in 3 sections, the first section is 120 ℃, and the time is as follows: 5 seconds; second stage 115 ℃, time: 5 seconds; the third stage was 110 ℃, time: for 5 seconds.
(5) Coating the antifogging agent: by reverse rotation of coating rollerThe coating amount of the antifogging agent emulsion formed by coating the antifogging agent emulsion on the liquid-resistant acrylic coating is 0.8g/m2The speed was 200 m/min.
The antifogging agent comprises the following components in percentage by mass:
(6) and (3) drying the antifogging agent: in the drying process, the tension is controlled as follows: 95N, the oven is divided into 4 sections, and the infrared temperature of the 1 st section is as follows: 125 ℃, time: for 3 seconds. The back 3 stages are electric heating ovens with a temperature of 115 ℃ and a time: 4S; second stage temperature 110 ℃, time: 4S; the third stage is at 100 ℃, time: for 5 seconds.
(7) A primary coating process: coating the aqueous polyurethane primer coating on the BOPET film corona by a reverse roll kiss type coating roll, and controlling the coating amount to be 0.7g/m by the mesh number and the speed of the coating roll2The number of the coating roller is 220 meshes, the speed of the coating roller is 230m/min, and the coating speed is 200 m/min.
The polyurethane primer coating comprises the following components in percentage by mass:
(8) and (3) primary coating drying: in the drying process, the tension is controlled as follows: 110N, the oven is an electric heating oven with 3 sections, the temperature of the 1 st section is as follows: at 120 ℃, for 3S; the temperature of the 2 nd section is 115 ℃, and the time is 3S; temperature at stage 3: 110 ℃, time: for 4 seconds.
(9) A top coating process: adopting a 120-mesh ceramic coating roller, coating PVDC emulsion on the polyurethane primer coating layer in a kiss mode at the reverse speed of 210m/min, and controlling the coating weight of the coating layer to be 2.8g/m2The coating speed was 200 m/min.
The PVDC emulsion is prepared from the following raw materials in parts by weight:
(10) a top coating and drying process: in the drying process, the tension is controlled as follows: 90N, the oven is divided into 4 sections, and the infrared temperature of the 1 st section is: 130 ℃, time: 3 seconds, the later 3 sections are electric heating ovens, the temperature is set progressively decreasing, the first section is 120 ℃, the time is as follows: 3S; stage 2 was 115 ℃ for the following times: 3S; stage 3 was 110 ℃, time: for 3 seconds.
(11) The subsequent process comprises the following steps: winding, detecting, rewinding and curing.
Example 3
The manufacturing of the antifogging high-barrier BOPET film provided by the embodiment of the invention is completed by the following steps:
(1) unwinding: the method is characterized in that a 25 mu m BOPET optical film roll is unfolded under the tension of 100N, the film roll continuously moves forwards through a plurality of guide rollers, two same stations are adopted to work alternately, and the purposes of continuously unreeling and changing rolls are achieved by utilizing automatic splicing and quick film changing.
(2) A corona treatment process: the corona electrode of the film passes through the corona electrode under the power of 8.0KW, and the surface of the film with the surface tension of 52 dyne value is uniformly processed on the non-corona surface of the film.
(3) Acrylic acid coating step: the liquid-resistant acrylic coating is coated on the corona surface of the BOPET optical film by a reverse roll kiss coating roll, and the coating amount can be 3.0g/m2The speed was 200 m/min.
The mass ratio of the acrylic coating is as follows:
(4) acrylic acid drying process: in the drying process, the tension is controlled as follows: 110N, the oven is divided into a plurality of sections, and the infrared temperature of the first section is as follows: 130 ℃, time: 2.0 seconds, the electric heating oven is in 3 sections, the first section is 120 ℃, and the time is as follows: 5 seconds; second stage 115 ℃, time: 5 seconds; the third stage was 110 ℃, time: for 5 seconds.
(5) Coating the antifogging agent: the antifogging agent emulsion is coated on the liquid-resistant acrylic coating by a reverse roll kiss coating roll to form the antifogging agent coating with the coating weight of 1.0g/m2The speed was 200 m/min.
The antifogging agent comprises the following components in percentage by mass:
(6) and (3) drying the antifogging agent: in the drying process, the tension is controlled as follows: 90N, the oven is divided into 4 sections, and the infrared temperature of the 1 st section is: 130 ℃, time: for 2 seconds. The back 3 stages are electric heating ovens, the temperature is 120 ℃, and the time is as follows: 5S; second stage temperature 115 ℃, time: 5S; the third stage was 110 ℃, time: for 5 seconds.
(7) A primary coating process: coating the aqueous polyurethane primer coating on the BOPET film corona by a reverse roll kiss type coating roll, and controlling the coating amount to be 1.0g/m by the mesh number and the speed of the coating roll2The number of the coating roller is 220 meshes, the speed of the coating roller is 240m/min, and the coating speed is 200 m/min.
The polyurethane primer coating comprises the following components in percentage by mass:
(8) and (3) primary coating drying: in the drying process, the tension is controlled as follows: 100N, the oven is an electric heating oven with 3 sections, the temperature of the 1 st section is as follows: at 120 ℃, for 3S; the temperature of the 2 nd section is 115 ℃, and the time is 3S; temperature at stage 3: 110 ℃, time: for 4 seconds.
(9) A top coating process: adopting a 120-mesh ceramic coating roller, coating the PVDC emulsion on the polyurethane primer coating in a kiss mode at a reverse speed of 220m/min, and controlling the coatingThe coating weight of the material layer was 3.1g/m2The coating speed was 200 m/min.
The PVDC emulsion is prepared from the following raw materials in parts by weight:
(10) a top coating and drying process: in the drying process, the tension is controlled as follows: 90N, the oven is divided into 4 sections, and the infrared temperature of the 1 st section is: 130 ℃, time: 3 seconds, the later 3 sections are electric heating ovens, the temperature is set progressively decreasing, the first section is 120 ℃, the time is as follows: 3S; stage 2 was 115 ℃ for the following times: 3S; stage 3 was 110 ℃, time: for 3 seconds.
(11) The subsequent process comprises the following steps: winding, detecting, rewinding and curing.
Product performance testing was performed according to conventional methods known in the art and the results were as follows:
TABLE 1 Properties of the products obtained in the examples of the invention
Test conditions/units
Example 1
Example 2
Example 3
Oxygen permeability
cc/m2/day
8.5
8.0
8.3
Water permeability
g/m2/day
3.8
3.3
3.9
Water-resistant drop test
Drip test with liquid for 24h
Without whitening
Without whitening
Without whitening
Heat seal strength
160℃*0.14MPa*1S，N/15mm
5.5
5.4
5.7
Haze degree
/
3.8
4.0
4.2
Degree of gloss
％
89
88
91
Cold and hot antifogging property
/
Superior food
Superior food
Superior food
From the above embodiments, the invention provides a high-barrier BOPET film for PET box sealing, which has a five-layer structure, and the five-layer structure sequentially comprises a PVDC coating layer, a polyurethane primer layer, a BOPET substrate layer, a liquid-resistant acrylic coating layer and an antifogging agent coating layer. Wherein the thickness of the BOPET substrate layer is 15-30 μm; the thickness ratio of the liquid-resistant acrylic coating to the antifogging agent coating is (0.5-1.5) mu m: (0.2-0.5) μm. The product has good heat-sealing strength with a PET box, antifogging effect and high transparency, and can achieve the effect of easy uncovering; meanwhile, the coating has good fresh-keeping and fragrance-keeping functions due to the excellent barrier effect. In addition, the base material of the film is PET, and the applied box material is also PET, so that the same material meeting the environmental protection requirement is recycled.
The BOPET heat-sealing antifogging cover film is prepared by a coating mode, the process is simple, the cost performance is high, great convenience and good customer experience are brought to the use of the packaging box, and the market and potential market capacity are huge.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.