Optical-grade protective film and production method thereof

Abstract

The invention discloses an optical-grade protective film and a production method thereof, and aims to solve the problem that an existing optical protective film is poor in wear resistance. According to the key points of the technical scheme, the composite film comprises a composite film layer, a core layer and a high polymer material layer, coating structures are arranged among the composite film layer, the core layer and the high polymer material layer, and each coating structure is composed of one or more of a resin material, an antioxidant, an anti-ultraviolet absorbent, an antistatic agent and a coloring material. Through the arrangement of the composite film layer and the multi-section stretching mode, the wear resistance and the tensile effect of the optical film are enhanced, and the service life of the optical protective film is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of optical protective films, and more particularly to an optical grade protective film and a production method thereof. Background Art

[0002] Various displays for TVs, computers, mobile phones, etc. have been developed and commercialized, for example, from light-receiving liquid crystal display devices (LCD) to light-emitting display devices such as OLED displays that have been commercialized recently. These display devices include optical films with various functions, which are arranged on the optical path of light from the light source until it leaves the front side on the viewer side, and the amount of light transmission, the direction of light, and other optical characteristics are optimally adjusted by the optical film, thereby improving characteristics such as brightness, viewing angle, and brightness.

[0003] On the other hand, recently, display devices need to be able to withstand use in various environments, such as use in more severe environments. For example, display devices of mobile devices such as mobile phones or display devices of vehicles such as car navigation systems need to have durability for use in more severe environments. In addition, in large display devices such as televisions, the interior of the display device tends to be exposed to high temperature environments due to the increase in heat generation caused by large size and high brightness. Therefore, various optical protective films used in display devices also need to have less characteristic changes in harsh environments such as high temperature and high humidity, that is, they need to have high durability.

[0004] Therefore, a solution needs to be proposed to solve this problem. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an optical-grade protective film and a production method thereof, which enhances the wear resistance and tensile effect of the optical film by setting a composite film layer and multi-stage stretching, thereby extending the service life of the optical protective film.

[0006] The above technical purpose of the present invention is achieved through the following technical scheme: an optical grade protective film, comprising a composite film layer, a core layer and a polymer material layer, wherein a coating structure is arranged between the composite film layer, the core layer and the polymer material layer, and the coating structure is composed of one or more components of a resin material, an antioxidant, an anti-ultraviolet absorber, an antistatic agent, and a colorant.

[0007] The present invention is further configured as follows: the thickness of the composite film layer accounts for 40%-60% of the total thickness, the thickness of the core layer accounts for 10%-20% of the total thickness, and the thickness of the polymer material layer accounts for 10%-30% of the total thickness.

[0008] The present invention is further configured as follows: the composite film layer is made by mixing engineering plastics with components such as antioxidants, anti-ultraviolet absorbers, antistatic agents, conductive agents, flame retardants, and colorants.

[0009] The present invention is further configured as follows: the engineering plastics include polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyimide, polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, and polyphenylene sulfide.

[0010] The present invention is further configured as follows: the core layer is composed of 100 parts of propylene block copolymer, 10-50 parts of metallocene-catalyzed propylene-α-olefin co-elastomer and 0.1-0.3 parts of antistatic agent.

[0011] The above technical purpose of the present invention is also achieved by the following technical solutions: A method for producing an optical grade protective film, comprising the following steps: Step a: Mix the three layers of raw materials in a closed container respectively, and then transport them into the silos of three extruders for melting through a special vacuum suction device, wherein each extruder and the die connection section has a filter to filter the melt to prevent unmelted materials and crystal points from entering the die;

[0012] Step b: The melts from the three extruders are combined in a die connector and then extruded through the die to obtain an unstretched sheet;

[0013] Step c: performing a first stretching of the unstretched sheet in the length direction (MD) by 3.0 to 3.3 times, and stretching the sheet in the width direction (TD) in multiple stages to perform a second stretching by a total of 3.3 to 3.7 times, and performing at least three stages of stretching, so that the stretching ratio of each stage becomes smaller toward the rear end, and the stretching is performed so that the width change rate in the last stretching stage is less than 20%, and the stretched sheet is heat-fixed to obtain a stretched sheet;

[0014] Step d: Cooling, online slitting, and rolling and packaging the stretched sheet to obtain a final protective film product.

[0015] In summary, the present invention has the following beneficial effects:

[0016] The present invention optimizes the structure and composition of the optical film, so that the optical film has excellent molding and processing properties and meets various molding and processing requirements; high surface hardness, wear resistance and scratch resistance can prevent scratches or damage to its surface, and the added coating structure can further enhance its surface hardness and scratch and wear resistance; excellent weather resistance and chemical resistance meet various application requirements; in addition, the optical film can provide excellent heat resistance and dimensional stability.

[0017] In the present invention, the antioxidant is added to enhance the antioxidant capacity of the material, thereby increasing the service life of the optical film; the anti-ultraviolet absorber can prevent the optical film from cracking, blistering, powdering, shedding and discoloration; the antistatic agent reduces the surface resistance of the material to the ohm level of 10 to the 9th power to 10 to the 13th power; and the conductive agent can further reduce the surface resistance of the material to the ohm level of 10 to the 3rd power to 10 to the 8th power; the flame retardant can improve the fireproof performance of the material; and the coloring material can be formulated into various required colors to meet the needs of users. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with specific embodiments. It should be noted that the embodiments of the present application and the features therein may be combined with each other without conflict.

[0019] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", "top / bottom" and the like indicating directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0020] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "set / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] The present invention is described in detail below.

[0022] An optical grade protective film comprises a composite film layer, a core layer and a polymer material layer, wherein a coating structure is arranged between the composite film layer, the core layer and the polymer material layer, and the coating structure is composed of one or more components of a resin material, an antioxidant, an anti-ultraviolet absorber, an antistatic agent and a coloring material.

[0023] The thickness of the composite film layer accounts for 40%-60% of the total thickness, the thickness of the core layer accounts for 10%-20% of the total thickness, and the thickness of the polymer material layer accounts for 10%-30% of the total thickness.

[0024] The composite film layer is made by mixing engineering plastics with components such as antioxidant, anti-ultraviolet absorber, antistatic agent, conductive agent, flame retardant and colorant.

[0025] The engineering plastics include polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyimide, polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, and polyphenylene sulfide.

[0026] The core layer is composed of 100 parts of propylene block copolymer, 10-50 parts of metallocene-catalyzed propylene-alpha-olefin co-elastomer and 0.1-0.3 parts of antistatic agent.

[0027] A method for producing an optical-grade protective film comprises the following steps: Step a: mixing three layers of raw materials in a sealed container respectively, and then conveying them into three extruder silos respectively through a dedicated vacuum suction device for melting, wherein a filter screen filter is provided at the connection section between each extruder and a die head to filter the melt to prevent unmelted materials and crystal points from entering the die head;

[0028] Step b: The melts from the three extruders are combined in a die connector and then extruded through the die to obtain an unstretched sheet;

[0029] Step c: performing a first stretching of the unstretched sheet in the length direction (MD) by 3.0 to 3.3 times, and stretching the sheet in the width direction (TD) in multiple stages to perform a second stretching by a total of 3.3 to 3.7 times, and performing at least three stages of stretching, so that the stretching ratio of each stage becomes smaller toward the rear end, and the stretching is performed so that the width change rate in the last stretching stage is less than 20%, and the stretched sheet is heat-fixed to obtain a stretched sheet;

[0030] Step d: Cooling, online slitting, and rolling and packaging the stretched sheet to obtain a final protective film product.

[0031] The present invention optimizes the structure and composition of the optical film, so that the optical film has excellent molding and processing properties and meets various molding and processing requirements; high surface hardness, wear resistance and scratch resistance can prevent scratches or damage to its surface, and the added coating structure can further enhance its surface hardness and scratch and wear resistance; excellent weather resistance and chemical resistance meet various application requirements; in addition, the optical film can provide excellent heat resistance and dimensional stability.

[0032] In the present invention, the antioxidant is added to enhance the antioxidant capacity of the material, thereby increasing the service life of the optical film; the anti-ultraviolet absorber can prevent the optical film from cracking, blistering, powdering, shedding and discoloration; the antistatic agent reduces the surface resistance of the material to the ohm level of 10 to the 9th power to 10 to the 13th power; and the conductive agent can further reduce the surface resistance of the material to the ohm level of 10 to the 3rd power to 10 to the 8th power; the flame retardant can improve the fireproof performance of the material; and the coloring material can be formulated into various required colors to meet the needs of users.

[0033] The polyester protective film of the present invention ensures moisture resistance, heat resistance and mechanical strength, and is therefore very suitable for use in protecting the functional layer of an optical film, and has the advantage of being able to reduce product costs due to its low unit price. In addition, unlike conventional optical polyester protective films, the visibility of rainbow spots caused by interference with transmitted light is significantly reduced, and when applied to various displays realized by applying various types of light sources, the influence of the light source type is minimized, thereby achieving excellent color reproducibility. In addition, by achieving the above-mentioned excellent and uniform optical properties within a further increased width, it is very suitable for use in optical devices such as large-area displays.

[0034] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. An optical grade protective film, characterized in that: It includes a composite film layer, a core layer and a polymer material layer, wherein a coating structure is arranged between the composite film layer, the core layer and the polymer material layer, and the coating structure is composed of one or more components of resin material, antioxidant, anti-ultraviolet absorber, antistatic agent and coloring material.

2. The optical grade protective film and the production method thereof according to claim 1, characterized in that: The thickness of the composite film layer accounts for 40%-60% of the total thickness, the thickness of the core layer accounts for 10%-20% of the total thickness, and the thickness of the polymer material layer accounts for 10%-30% of the total thickness.

3. The optical grade protective film and the production method thereof according to claim 1, characterized in that: The composite film layer is made by mixing engineering plastics with components such as antioxidant, anti-ultraviolet absorber, antistatic agent, conductive agent, flame retardant and colorant.

4. The optical grade protective film and the production method thereof according to claim 3, characterized in that: The engineering plastics include polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyimide, polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, and polyphenylene sulfide.

5. The optical grade protective film and the production method thereof according to claim 1, characterized in that: The core layer is composed of 100 parts of propylene block copolymer, 10-50 parts of metallocene-catalyzed propylene-alpha-olefin co-elastomer and 0.1-0.3 parts of antistatic agent.

6. A method for producing an optical grade protective film according to any one of claims 1 to 5, characterized in that: Includes the following Steps: Step a: The three layers of raw materials are mixed in a sealed container respectively, and then transported to the three extruder silos for melting through a special vacuum suction device. The connection section between each extruder and the die head is equipped with a filter to filter the melt to prevent unmelted materials and crystal points from entering the die head; Step b: The melts from the three extruders are combined in a die connector and then extruded through the die to obtain an unstretched sheet; Step c: performing a first stretching of the unstretched sheet in the length direction (MD) by 3.0 to 3.3 times, and stretching the sheet in the width direction (TD) in multiple stages to perform a second stretching by a total of 3.3 to 3.7 times, and performing at least three stages of stretching, so that the stretching ratio of each stage becomes smaller toward the rear end, and the stretching is performed so that the width change rate in the last stretching stage is less than 20%, and the stretched sheet is heat-fixed to obtain a stretched sheet; Step d: Cooling, online slitting, and rolling and packaging the stretched sheet to obtain a final protective film product.