Polymer films and uses thereof

Abstract

To provide a polymer film which is effective for producing laminated glass which exhibits good structural uniformity, has an excellent sound insulation function and has no optical defects.SOLUTION: There is provided a polymer film comprising a first layer, a second layer and a third layer in this order, wherein two surfaces of the second layer are in contact with the first layer and the third layer, respectively. The first layer has a first melt index, the second layer has a second melt index and the third layer has a third melt index. The second melt index is in the range of 3.5 g / 10 min to 10.0 g / 10 min, the first melt index and the third melt index are each independently lower than 3.5 g / 10 min and the difference between the second melt index and the first melt index and the difference between the second melt index and the third melt index are each independently in the range of 0.2 g / 10 min to 8.5 g / 10 min.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a polymer film, in particular to a multilayer polymer film having specific melt index (MI) properties, and to a laminated glass produced using the polymer film. [Background technology]

[0002] Laminated glass is a composite glass material made by sandwiching a polymer film between two glass sheets and bonding the glass sheets and the polymer film together using a heat press. Laminated glass is widely used in the automotive and construction industries due to its excellent impact resistance and safety.

[0003] The polymer film of the laminated glass can adopt a multi-layer structure to give the laminated glass a specific function. For example, a laminated glass with sound insulation function can be produced by adopting a polymer film including two outer layers and one intermediate sound insulation layer, the latter being located between the two outer layers. In general, the polymer film used to produce the laminated glass with sound insulation function needs to have a certain thickness as a sound insulation intermediate layer and an overall uniform structure to effectively attenuate the vibration of sound, thereby achieving sound insulation. Summary of the Invention [Means for solving the problem]

[0004] The present invention provides a polymer film having a multi-layer structure, which exhibits good structural uniformity through the synergistic application of materials with specific melt indexes, and is effective in producing laminated glass having excellent sound insulation function and no optical defects. Therefore, the polymer film of the present invention is particularly suitable for producing sound-insulating laminated glass.

[0005] It is therefore an object of the present invention to provide a polymer film comprising, in order, a first layer, a second layer and a third layer, wherein two surfaces of the second layer are in contact with the first layer and the third layer, respectively, the first layer having a first melt index, the second layer having a second melt index and the third layer having a third melt index, the second melt index being in the range of 3.5 g / 10 min to 10.0 g / 10 min, the first melt index and the third melt index being independently lower than 3.5 g / 10 min, and the difference between the second melt index and the first melt index and the difference between the second melt index and the third melt index being independently in the range of 0.2 g / 10 min to 8.5 g / 10 min.

[0006] In some embodiments of the present invention, the first melt index and the third melt index are independently in the range of 1.5 g / 10 min to 3.3 g / 10 min.

[0007] In some embodiments of the present invention, the first melt index, the second melt index and the third melt index are measured according to ASTM D1238 at 190° C. and under a load of 2.16 kg.

[0008] In some embodiments of the invention, the first layer, the second layer, and the third layer are independently comprised of polyvinyl acetal, which may be selected from the group consisting of poly(vinyl formal), poly(vinyl acetal), poly(vinyl butyral), poly(vinyl pentanal), poly(vinyl hexanal), and combinations thereof. In a preferred embodiment of the invention, the first layer, the second layer, and the third layer are independently comprised of poly(vinyl butyral).

[0009] In some embodiments of the present invention, based on the total molar numbers of hydroxyl groups, acetal groups, and acetyl groups of the polyvinyl acetal contained in the second layer, the polyvinyl acetal contained in the second layer has a degree of acetalization in the range of 56 mol% to 74 mol%, a degree of acetylation in the range of 5 mol% to 15 mol%, and a hydroxyl group content in the range of 20 mol% to 30 mol%.

[0010] In some embodiments of the present invention, based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups of the polyvinyl acetal contained in each of the first layer and the third layer, the polyvinyl acetal contained in the first layer and the polyvinyl acetal contained in the third layer independently have a degree of acetalization in the range of 60 mol% to 75 mol%, a degree of acetylation in the range of 0.1 mol% to 5 mol%, and a hydroxyl group content in the range of 20 mol% to 35 mol%.

[0011] In some embodiments of the present invention, the number average molecular weight (Mn) of the polyvinyl acetal contained in the second layer is in the range of 100,000 to 240,000.

[0012] In some embodiments of the present invention, the polyvinyl acetal in the first layer and the polyvinyl acetal in the third layer independently have a number average molecular weight (Mn) in the range of 90,000 to 120,000.

[0013] In some embodiments of the present invention, the first layer, the second layer, and the third layer independently further comprise a plasticizer.

[0014] In some embodiments of the present invention, the first layer, the second layer, and the third layer each independently further comprise a plasticizer. Based on 100 parts by weight of the polyvinyl acetal contained in the first layer, the amount of the plasticizer contained in the first layer is in the range of 30 parts by weight to 50 parts by weight. Based on 100 parts by weight of the polyvinyl acetal contained in the second layer, the amount of the plasticizer contained in the second layer is in the range of 55 parts by weight to 85 parts by weight. Based on 100 parts by weight of the polyvinyl acetal contained in the third layer, the amount of the plasticizer contained in the third layer is in the range of 30 parts by weight to 50 parts by weight.

[0015] Another object of the present invention is to provide a laminated glass, which comprises, in order, a first glass sheet, an intermediate film and a second glass sheet, the intermediate film being provided by the aforementioned polymer film.

[0016] In order to make the above objectives, technical features and advantages of the present invention more apparent, the present invention will be described in detail below with reference to several embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, some embodiments of the present invention will be described in detail. However, the present invention may be embodied in various embodiments and should not be limited to the embodiments set forth in the specification.

[0018] Unless otherwise specified, the terms "a", "the", and the like in the specification and claims are intended to include both the singular and the plural.

[0019] Unless otherwise specified, the terms "first", "second", and the like in the specification and claims are used merely to distinguish between exemplified elements or components without any special meaning, and are not used to indicate priority.

[0020] In this specification and claims, "Melt Index (MI)" is measured according to ASTM D1238 at 190° C. and under a load of 2.16 kg.

[0021] In this specification and claims, the unit of number average molecular weight (Mn) is "Daltons".

[0022] The present invention provides a polymer film with good structural uniformity. The polymer film of the present invention is useful for producing laminated glass with excellent sound insulation function and no optical defects. The polymer film of the present invention and its uses will be described in detail below.

[0023] 1. Polymer film

[0024] 1.1.Physical properties of polymer films

[0025] The polymer film of the present invention comprises, in order, a first layer, a second layer and a third layer, and the two surfaces of the second layer (i.e., the intermediate sound insulation layer) are in contact with the first layer and the third layer, respectively.

[0026] In the polymer film of the present invention, the second layer has a second melt index in the range of 3.5 g / 10 min to 10.0 g / 10 min. For example, the second melt index is 3.5 g / 10 min, 3.6 g / 10 min, 3.7 g / 10 min, 3.8 g / 10 min, 3.9 g / 10 min, 4.0 g / 10 min, 4.1 g / 10 min, 4.2 g / 10 min, 4.3 g / 10 min, 4.4 g / 10 min, 4.5 g / 10 min, 4.6 g / 10 min, 4.7 g / 10 min, 4.8 g / 10 min, 4.9 g / 10 min, 5.0 g / 10 min, 5.1g / 10 minutes, 5.2g / 10 minutes, 5.3g / 10 minutes, 5.4g / 10 minutes, 5.5g / 10 minutes, 5.6g / 10 minutes, 5.7g / 10 minutes, 5.8g / 10 minutes, 5.9g / 10 minutes, 6.0g / 10 minutes, 6.1g / 10 minutes, 6.2g / 10 minutes, 6.3g / 10 minutes, 6.4g / 10 minutes, 6.5g / 10 minutes, 6.6g / 10 minutes, 6.7g / 10 minutes, 6.8g / 10 minutes, 6.9g / 10 minutes, 7.0g / 10 minutes, 7.1g / 10 minutes, 7.2g / 10 minutes, 7.3g / 10 minutes, 7.4g / 10 minutes, 7.5g / 10 minutes, 7.6g / 10 minutes, 7.7g / 10 minutes, 7.8g / 10 minutes, 7.9g / 10 minutes, 8.0g / 10 minutes, 8.1g / 10 minutes, 8.2g / 10 minutes, 8.3g / 10 minutes, 8.4g / 10 minutes, 8.5g / 10 minutes, 8.6g / 10 minutes, The melt index of the second layer may be 8.7g / 10min, 8.8g / 10min, 8.9g / 10min, 9.0g / 10min, 9.1g / 10min, 9.2g / 10min, 9.3g / 10min, 9.4g / 10min, 9.5g / 10min, 9.6g / 10min, 9.7g / 10min, 9.8g / 10min, 9.9g / 10min, or 10.0g / 10min, or within a range between any two values ​​listed herein. The second layer having a predetermined melt index may attenuate sound vibrations, thereby optimizing the sound insulation effect.

[0027] In the polymer film of the present invention, the first layer has a first melt index and the third layer has a third melt index. The first melt index and the third melt index are independently lower than 3.5 g / 10 min. Preferably, the first melt index and the third melt index are independently in the range of 1.5 g / 10 min to 3.3 g / 10 min. For example, the first melt index and the third melt index can independently be 1.5 g / 10 min, 1.6 g / 10 min, 1.7 g / 10 min, 1.8 g / 10 min, 1.9 g / 10 min, 2.0 g / 10 min, 2.1 g / 10 min, 2.2 g / 10 min, 2.3 g / 10 min, 2.4 g / 10 min, 2.5 g / 10 min, 2.6 g / 10 min, 2.7 g / 10 min, 2.8 g / 10 min, 2.9 g / 10 min, 3.0 g / 10 min, 3.1 g / 10 min, 3.2 g / 10 min, 3.3 g / 10 min, or 3.4 g / 10 min, or within a range between any two of the values ​​recited herein.

[0028] In the polymer film of the present invention, the difference between the second melt index and the first melt index, and the difference between the second melt index and the third melt index, are independently within the range of 0.2 g / 10 min to 8.5 g / 10 min. For example, the difference between the second melt index and the first melt index, and the difference between the second melt index and the third melt index, are independently within the range of 0.2 g / 10 min, 0.3 g / 10 min, 0.4 g / 10 min, 0.5 g / 10 min, 0.6 g / 10 min, 0.7 g / 10 min, 0.8 g / 10 min, 0.9 g / 10 min, 1.0 g / 10 min, 1.1 g / 10 min, 1.2 g / 10 min, 1.3 g / 10 min, 1.4 g / 10 min, 1.5 g / 10 min, 1.6 g / 10 min, 1.7 g / 10 min, 1.8g / 10 minutes, 1.9g / 10 minutes, 2.0g / 10 minutes, 2.1g / 10 minutes, 2.2g / 10 minutes, 2.3g / 10 minutes, 2.4g / 10 minutes, 2.5g / 10 minutes, 2.6g / 10 minutes, 2.7g / 10 minutes, 2.8g / 10 minutes, 2.9g / 10 minutes, 3.0g / 10 minutes, 3.1g / 10 minutes, 3.2g / 10 minutes, 3.3g / 10 minutes, 3.4g / 10 minutes, 3.5g / 10 minutes, 3.6g / 10 minutes, 3.7g / 10 minutes, 3.8g / 10 minutes, 3.9g / 10 minutes, 4.0g / 10 minutes, 4.1g / 10 minutes, 4.2g / 10min, 4.3g / 10min, 4.4g / 10min, 4.5g / 10min, 4.6g / 10min, 4.7g / 10min, 4.8g / 10min, 4.9g / 10min, 5.0g / 10min, 5.1g / 10min, 5.2g / 10min, 5.3g / 10min, 5.4g / 10 minutes, 5.5g / 10 minutes, 5.6g / 10 minutes, 5.7g / 10 minutes, 5.8g / 10 minutes, 5.9g / 10 minutes, 6.0g / 10 minutes, 6.1g / 10 minutes, 6.2g / 10 minutes, 6.3g / 10 minutes, 6.4g / 10 minutes, 6.5g / 10 minutes, The viscosity may be 6.6g / 10min, 6.7g / 10min, 6.8g / 10min, 6.9g / 10min, 7.0g / 10min, 7.1g / 10min, 7.2g / 10min, 7.3g / 10min, 7.4g / 10min, 7.5g / 10min, 7.6g / 10min, 7.7g / 10min, 7.8g / 10min, 7.9g / 10min, 8.0g / 10min, 8.1g / 10min, 8.2g / 10min, 8.3g / 10min, 8.4g / 10min, or 8.5g / 10min, or within a range between any two of the values ​​recited herein.

[0029] The inventors have found that only when the melt indexes of the first, second and third layers are within a certain range can the polymer film achieve good structural uniformity, resulting in a laminated glass with excellent sound insulation function and no optical defects. In addition, the difference between the second melt index and the first melt index, and the difference between the second melt index and the third melt index, must also be within a certain range. "Good structural uniformity" refers to the presence of the first, second and third layers throughout the polymer film in a complete and continuous manner, without interruption or discontinuity at the second layer. In addition, the second layer must have a desired thickness and good thickness uniformity (thickness deviation not exceeding 0.025 mm).

[0030] 1.2. Polymer film composition

[0031] The polymer film of the present invention has a first layer, a second layer and a third layer in order, and the two surfaces of the second layer are in contact with the first layer and the third layer, respectively. In other words, the second layer is between the first layer and the third layer. Alternatively, the polymer film of the present invention may be substantially composed of a first layer, a second layer and a third layer in this order, and both sides of the second layer are in contact with the first layer and the third layer, respectively. Alternatively, the polymer film of the present invention may be composed of a first layer, a second layer and a third layer in this order, and both sides of the second layer are in contact with the first layer and the third layer, respectively.

[0032] In the polymer film of the present invention, the first layer, the second layer and the third layer may each independently contain polyvinyl acetal as an essential component, and the first layer, the second layer and the third layer may each independently further contain other optional components such as plasticizers or other conventional additives, if necessary. In this specification, the expression "the first layer, the second layer and the third layer independently contain polyvinyl acetal" means that the first layer, the second layer and the third layer each contain polyvinyl acetal, and the polyvinyl acetals contained in these layers may be the same or different. In some embodiments of the present invention, the first layer, the second layer and the third layer each independently contain polyvinyl acetal and a plasticizer, and the polyvinyl acetal and the plasticizer contained in these layers may be the same or different. Alternatively, the first layer, the second layer, and the third layer each independently consist essentially of polyvinyl acetal and a plasticizer, and the polyvinyl acetal and the plasticizer contained in each layer may be the same or different. Alternatively, the first layer, the second layer, and the third layer each independently consist essentially of polyvinyl acetal and a plasticizer, and the polyvinyl acetal and the plasticizer contained in each layer may be the same or different.

[0033] The first layer, the second layer and the third layer of the polymer film of the present invention may be a single layer film composed of one layer or a multilayer film composed of multiple layers, as long as the polymer film as a whole has a melt index set. In some embodiments of the present invention, the first layer, the second layer and the third layer are each a single layer film composed of one single layer.

[0034] 1.2.1. Polyvinyl acetal

[0035] Examples of polyvinyl acetals include, but are not limited to, poly(vinyl formal), poly(vinyl acetal), poly(vinyl butyral), poly(vinyl pentanal), poly(vinyl hexanal), etc. The above polyvinyl acetals can be used alone or in combination of two or more. In a preferred embodiment of the present invention, the polyvinyl acetal is poly(vinyl butyral).

[0036] 1.2.1.1. Polyvinyl acetal in the second layer

[0037] In some embodiments of the present invention, the number average molecular weight (Mn) of the polyvinyl acetal contained in the second layer is in the range of 100,000 to 240,000. For example, the Mn of the polyvinyl acetal contained in the second layer is 100,000, 105,000, 110,000, 115,000, 120,000, 125,000, 130,000, 135,000, 140,000, 145,000, 150,000, 155,000, 160,000, 165,000, 170,000 , 175,000, 180,000, 185,000, 190,000, 195,000, 200,000, 205,000, 210,000, 215,000, 220,000, 225,000, 230,000, 235,000, or 240,000, or within a range between any two values ​​described herein. Generally, the higher the number average molecular weight of a polymer, the higher the degree of polymerization of the polymer, and therefore the lower the polymer's fluidity and the lower the polymer's melt index. Conversely, the lower the number average molecular weight of a polymer, the higher the polymer's melt index.

[0038] In some embodiments of the present invention, the content of acetal groups in the polyvinyl acetal contained in the second layer (i.e., the degree of acetalization) based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups in the polyvinyl acetal contained in the second layer may be in the range of 56 mol% to 74 mol%. For example, the acetalization degree of the polyvinyl acetal contained in the second layer based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups in the polyvinyl acetal contained in the second layer may be in the range of 56 mol%, 56.5 mol%, 57 mol%, 57.5 mol%, 58 mol%, 58.5 mol%, 59 mol%, 59.5 mol%, 60 mol%, 60.5 mol%, 61 mol%, 61.5 mol%, 62 mol%, 62.5 mol%, 63 mol%, 63 mol%, 64 mol%, 65 mol%, 66 mol%, 67 mol%, 68 mol%, 69 mol%, 70 mol%, 71 mol%, 72 mol%, 73 mol%, 74 mol%, 75 mol%, 76 mol%, 77 mol%, 78 mol%, 79 mol%, 80 mol%, 81 mol%, 82 mol%, 83 mol%, 84 mol%, 85 mol%, 86 mol%, 87 mol%, 88 mol%, 89 mol%, 90 mol%, 91 mol%, 92 mol%, 93 mol%, 94 mol%, 95 mol%, 96 mol%, 97 mol%, 98 mol%, 99 mol%, 98 mol%, 99 mol%, 99 mol%, 100 The degree of acetalization of the polyvinyl acetal contained in the second layer may be in the range of 60 mol% to 71 mol%, based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups of the polyvinyl acetal contained in the second layer.

[0039] In some embodiments of the present invention, the content of acetyl groups (i.e., the degree of acetylation) of the polyvinyl acetal contained in the second layer may be in the range of 5 mol% to 15 mol% based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups of the polyvinyl acetal contained in the second layer. For example, the degree of acetylation of the polyvinyl acetal contained in the second layer may be 5 mol%, 5.5 mol%, 6 mol%, 6.5 mol%, 7 mol%, 7.5 mol%, 8 mol%, 8.5 mol%, 9 mol%, 9.5 mol%, 10 mol%, 10.5 mol%, 11 mol%, 11.5 mol%, 12 mol%, 12.5 mol%, 13 mol%, 13.5 mol%, 14 mol%, 14.5 mol%, or 15 mol%, or within a range between any two values ​​described herein based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups of the polyvinyl acetal contained in the second layer. In a preferred embodiment of the present invention, the degree of acetylation of the polyvinyl acetal contained in the second layer is in the range of 7 mol% to 12 mol%, based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups of the polyvinyl acetal contained in the second layer.

[0040] In some embodiments of the present invention, the content of hydroxyl groups in the polyvinyl acetal contained in the second layer may be in the range of 20 mol% to 30 mol%, based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups in the polyvinyl acetal contained in the second layer. For example, based on the total molar number of hydroxyl groups, acetal groups, and acetyl groups in the polyvinyl acetal contained in the second layer, the hydroxyl group content of the polyvinyl acetal contained in the second layer can be 20 mol%, 20.5 mol%, 21 mol%, 21.5 mol%, 22 mol%, 22.5 mol%, 23 mol%, 23.5 mol%, 24 mol%, 24.5 mol%, 25 mol%, 25.5 mol%, 26 mol%, 26.5 mol%, 27 mol%, 27.5 mol%, 28 mol%, 28.5 mol%, 29 mol%, 29.5 mol%, or 30 mol%, or a range between any two values ​​recited herein. In a preferred embodiment of the present invention, the hydroxyl group content of the polyvinyl acetal contained in the second layer is in the range of 22 mol% to 28 mol% based on the total molar number of the hydroxyl group, acetal group, and acetyl group of the polyvinyl acetal contained in the second layer. The lower the hydroxyl group content of the polyvinyl acetal, the greater the amount of plasticizer that the polyvinyl acetal can absorb.

[0041] 1.2.1.2. Polyvinyl acetal contained in the first and third layers

[0042] In some embodiments of the present invention, the number average molecular weight (Mn) of the polyvinyl acetal contained in the first layer and the number average molecular weight (Mn) of the polyvinyl acetal contained in each of the third layers are independently in the range of 90,000 to 120,000. For example, the Mn of the polyvinyl acetal contained in the first layer and the Mn of the polyvinyl acetal contained in the third layer are independently in the range of 90,000, 91,000, 92,000, 93,000, 94,000, 95,000, 96,000, 97,000, 98,000, 99,000, 100,000, 101,000, 102,000, 103,000, 104,000, 105,000, 106,000, 107,000, 108,000, 109,000, 200,000, 210,000, 220,000, 230,000, 240,000, 250,000, 260,000, 270,000, 280,000, 290,000, 300,000, 310,000, 320,000, 330,000, 340,000, 350,000, 360,000, 370,000, 380,000, 390,000, 400,000, 410,000, 420,000, 430,000, 440, 00, 105,000, 106,000, 107,000, 108,000, 109,000, 110,000, 111,000, 112,000, 113,000, 114,000, 115,000, 116,000, 117,000, 118,000, 119,000, or 120,000, or within a range between any two values ​​listed herein.

[0043] In some embodiments of the present invention, the content of acetal groups in the polyvinyl acetal contained in each of the first layer and the third layer (i.e., the degree of acetalization) can be independently in the range of 60 mol% to 75 mol% based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups in the polyvinyl acetal contained in each of the first layer and the third layer. For example, the acetalization degree of the polyvinyl acetal contained in each of the first layer and the third layer can be independently in the range of 60 mol%, 60.5 mol%, 61 mol%, 61.5 mol%, 62 mol%, 62.5 mol%, 63 mol%, 63.5 mol%, 64 mol%, 64.5 mol%, 65 mol% based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups in the polyvinyl acetal contained in each of the first layer and the third layer. , 65.5 mol%, 66 mol%, 66.5 mol%, 67 mol%, 67.5 mol%, 68 mol%, 68.5 mol%, 69 mol%, 69.5 mol%, 70 mol%, 70.5 mol%, 71 mol%, 71.5 mol%, 72 mol%, 72.5 mol%, 73 mol%, 73.5 mol%, 74 mol%, 74.5 mol%, or 75 mol%, or a range between any two values ​​described herein. In a preferred embodiment of the present invention, the degree of acetalization of the polyvinyl acetal contained in each of the first layer and the third layer is independently in the range of 70 mol% to 72 mol%, based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups of the polyvinyl acetal contained in each of the first layer and the third layer.

[0044] In some embodiments of the present invention, the content of acetyl groups (i.e., the degree of acetylation) of the polyvinyl acetal contained in each of the first layer and the third layer can be independently in the range of 0.1 mol% to 5 mol% based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups of the polyvinyl acetal contained in each of the first layer and the third layer. For example, the acetylation degree of the polyvinyl acetal contained in each of the first layer and the third layer can be independently in the range of 0.1 mol%, 0.5 mol%, 1 mol%, 1.5 mol%, 2 mol%, 2.5 mol%, 3 mol%, 3.5 mol%, 4 mol%, 4.5 mol%, or 5 mol%, or within a range between any two values ​​described herein based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups of the polyvinyl acetal contained in each of the first layer and the third layer. In a preferred embodiment of the present invention, the polyvinyl acetal contained in each of the first layer and the third layer independently has a degree of acetylation in the range of 0.5 mol % to 1.5 mol %, based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups of the polyvinyl acetal contained in each of the first layer and the third layer.

[0045] In some embodiments of the present invention, the hydroxyl group content of the polyvinyl acetal contained in each of the first layer and the third layer can be independently in the range of 20 mol% to 35 mol% based on the total number of moles of the hydroxyl group, acetal group, and acetyl group of the polyvinyl acetal contained in each of the first layer and the third layer. For example, the hydroxyl group content of the polyvinyl acetal contained in each of the first layer and the third layer can be independently in the range of 20 mol%, 20.5 mol%, 21 mol%, 21.5 mol%, 22 mol%, 22.5 mol%, 23 mol%, 23.5 mol%, 24 mol%, 24.5 mol%, 25 mol%, 26 mol%, 27 mol%, 28 mol%, 29 mol%, 30 mol%, 31 mol%, 32 mol%, 33 mol%, 34 mol%, 35 mol%, 36 mol%, 37 mol%, 38 mol%, 39 mol%, 40 mol%, 41 mol%, 42 mol%, 43 mol%, 44 mol%, 45 mol%, 46 mol%, 47 mol%, 48 mol%, 49 mol%, 50 mol%, 51 mol%, 52 mol%, 53 mol%, 54 mol%, 55 mol%, 56 mol%, 57 mol%, 58 mol%, 59 ... 1%, 25.5 mol%, 26 mol%, 26.5 mol%, 27 mol%, 27.5 mol%, 28 mol%, 28.5 mol%, 29 mol%, 29.5 mol%, 30 mol%, 30.5 mol%, 31 mol%, 31.5 mol%, 32 mol%, 32.5 mol%, 33 mol%, 33.5 mol%, 34 mol%, 34.5 mol%, or 35 mol%, or within a range between any two values ​​described herein. In a preferred embodiment of the present invention, the hydroxyl group content of the polyvinyl acetal contained in each of the first layer and the third layer is independently in the range of 27 mol% to 29 mol%, based on the total number of moles of hydroxyl groups, acetal groups, and acetyl groups of the polyvinyl acetal contained in each of the first layer and the third layer.

[0046] Plasticizers

[0047] A plasticizer, as used herein, is also called a plasticizer, and is a chemical substance that can modify the plasticity of a thermoplastic resin. In general, the more the amount of plasticizer added, the higher the melt index of the polymer film. The type of plasticizer is not particularly limited, and the plasticizers contained in the first layer, the second layer, and the third layer may be the same or different. Examples of plasticizers include triethylene glycol bis(2-ethylhexanoate), tetraethylene glycol bis(2-ethylhexanoate), triethylene glycol bis(2-ethylbutyrate), tetraethylene glycol bis(2-ethylbutyrate), triethylene glycol diheptanoate, tetraethylene glycol diheptanoate, dihexyl adipate, dioctyl adipate, hexylcyclohexyl adipate, diisononyl adipate, heptylnonyl adipate, dibutyl sebacate, bis[2-(2-butanoyl)-1,3-dimethylphenyl]-2,4 ... Examples of suitable plasticizers include, but are not limited to, esters of polybasic acids or polyhydric alcohols such as bis(2-ethylhexyl)(oxyethoxy)ethyl)adipate, polymeric adipate, dipropylene glycol dibenzoate, tripropylene glycol dibenzoate, polypropylene glycol dibenzoate, isodecyl benzoate, 2-ethylhexyl benzoate, propylene glycol dibenzoate, diisononyl phthalate, dibutoxyethyl terephthalate, castor oil, methyl ricinoleate, soybean oil, epoxidized soybean oil, and combinations thereof. In the accompanying examples, triethylene glycol bis(2-ethylhexanoate) is used as the plasticizer.

[0048] In some embodiments of the present invention, the amount of plasticizer contained in the first layer is in the range of 30 parts by weight to 50 parts by weight based on 100 parts by weight of polyvinyl acetal contained in the first layer. For example, the amount of plasticizer contained in the first layer is 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, or 50 parts by weight, or within a range between any two values ​​described herein. In a preferred embodiment of the present invention, the amount of plasticizer contained in the first layer is in the range of 38 parts by weight to 44 parts by weight based on 100 parts by weight of polyvinyl acetal contained in the first layer.

[0049] In some embodiments of the present invention, the amount of plasticizer contained in the second layer is in the range of 55 parts by weight to 85 parts by weight based on 100 parts by weight of the polyvinyl acetal contained in the second layer. For example, based on 100 parts by weight of polyvinyl acetal in the second layer, the amount of plasticizer in the second layer can be 55 parts by weight, 56 parts by weight, 57 parts by weight, 58 parts by weight, 59 parts by weight, 60 parts by weight, 61 parts by weight, 62 parts by weight, 63 parts by weight, 64 parts by weight, 65 parts by weight, 66 parts by weight, 67 parts by weight, 68 parts by weight, 69 parts by weight, 70 parts by weight, 71 parts by weight, 72 parts by weight, 73 parts by weight, 74 parts by weight, 75 parts by weight, 76 parts by weight, 77 parts by weight, 78 parts by weight, 79 parts by weight, 80 parts by weight, 81 parts by weight, 82 parts by weight, 83 parts by weight, 84 parts by weight, or 85 parts by weight, or within a range between any two of the values ​​recited herein. In a preferred embodiment of the present invention, the amount of plasticizer contained in the second layer is in the range of 60 parts by weight to 80 parts by weight based on 100 parts by weight of the polyvinyl acetal contained in the second layer.

[0050] In some embodiments of the present invention, the amount of the plasticizer contained in the third layer is in the range of 30 parts by weight to 50 parts by weight based on 100 parts by weight of the polyvinyl acetal contained in the third layer. For example, the amount of the plasticizer contained in the third layer can be 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, or 50 parts by weight, or within a range between any two values ​​described herein. In a preferred embodiment of the present invention, the amount of the plasticizer contained in the third layer is in the range of 38 parts by weight to 44 parts by weight based on 100 parts by weight of the polyvinyl acetal contained in the third layer.

[0051] 1.2.3. Other conventional additives

[0052] Conventional additives include any material that can appropriately improve the processability of polymer film during the production of polymer film, or can impart specific functions to polymer film. The specific functions include, but are not limited to, one or more of heat insulation function, reflection function, anti-reflection function, refraction function, anti-refraction function, light division function, and light control function.

[0053] Examples of conventional additives include, but are not limited to, dyes, pigments, stabilizers, antioxidants, flame retardants, infrared absorbers, infrared blocking agents, ultraviolet absorbers, ultraviolet stabilizers, lubricants, dispersants, surfactants, chelating agents, coupling agents, binders, and adhesion control agents. For example, the polymer film may contain dyes or pigments to form a colored polymer film. The polymer film may also contain ultraviolet absorbers or infrared absorbers to form a polymer film having ultraviolet protection or infrared protection functions. The above additives may be used alone or in combination of two or more. Furthermore, the above additives may be added to one or more of the first, second, and third layers of the polymer film.

[0054] 1.3. Other physical properties of polymer films

[0055] Provided that the polymer film meets a certain melt index requirement, the total thickness of the polymer film and the thickness of each of the first layer, the second layer, and the third layer of the polymer film can be adjusted as necessary.Generally, the total thickness of the polymer film of the present invention can be 0.1mm to 2.5mm, for example, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1.0mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm. The thickness of the polymer film may be 1.3 mm, 1.35 mm, 1.4 mm, 1.45 mm, 1.5 mm, 1.55 mm, 1.6 mm, 1.65 mm, 1.7 mm, 1.75 mm, 1.8 mm, 1.85 mm, 1.9 mm, 1.95 mm, 2.0 mm, 2.05 mm, 2.1 mm, 2.15 mm, 2.2 mm, 2.25 mm, 2.3 mm, 2.35 mm, 2.4 mm, 2.45 mm, or 2.5 mm, or within a range between any two values ​​listed herein. In the accompanying examples, the polymer film has a thickness of 0.76 mm to 0.85 mm.

[0056] In some embodiments of the invention, the thickness of the first layer and the thickness of the third layer can independently be from 250 μm to 450 μm, e.g., 250 μm, 260 μm, 270 μm, 280 μm, 290 μm, 300 μm, 310 μm, 320 μm, 330 μm, 340 μm, 350 μm, 360 μm, 370 μm, 380 μm, 390 μm, 400 μm, 410 μm, 420 μm, 430 μm, 440 μm, or 450 μm, or within a range between any two values ​​recited herein.

[0057] In some embodiments of the invention, the thickness of the second layer can be from 50 μm to 250 μm, e.g., 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm, or 250 μm, or a range between any two values ​​recited herein.

[0058] 1.4. Polymer film production

[0059] The method for producing the polymer film of the present invention is not particularly limited. For example, the polymer film of the present invention may be produced by mixing polyvinyl acetal and optional components (e.g., plasticizer), dry stirring and kneading to obtain a polymer composition, using the polymer composition to obtain a polymer film by a conventional film forming method, and performing a mechanical embossing process on the surface of the polymer film. Examples of conventional film forming methods include, but are not limited to, a calendar method, a casting method, an extrusion stretching method, a direct extrusion method, an extrusion blow method, etc.

[0060] In some embodiments of the present invention, the polymer film is produced as follows, but the present invention is not limited thereto: a first polymer film composition for producing the first layer and the third layer, and a second polymer film composition for producing the second layer are prepared, and then the first polymer film composition and the second polymer film composition are put into a co-extruder to form the polymer film of the present invention by co-extrusion.

[0061] The first polymer film composition and the second polymer film composition can be prepared independently as follows, but the present invention is not limited thereto: preheat the selected polyvinyl acetal resin in an oven, dry-stir the preheated polyvinyl acetal and plasticizer to obtain a dry-stirred mixture, and then knead the dry-stirred mixture using a twin-screw kneader to obtain the desired first polymer film composition or second polymer film composition.

[0062] Without being limited by any theory, it is believed that the melt index of a polymer film can be adjusted by controlling the amount of functional groups of the polymer, the amount of plasticizer in the polymer film, and the uniformity of absorption of the plasticizer in the polymer. The uniformity of absorption of the plasticizer in the polymer can be adjusted by controlling the preheating temperature, dry stirring temperature, dry stirring time, kneading temperature, and kneading time during the production of the polymer film. In general, preheating expands the pores between the polymer materials to slightly increase the fluidity of the resin, making it easier to mix with the plasticizer thereafter. Increasing the dry stirring temperature promotes the expansion of the pores and promotes the absorption of the plasticizer. Increasing the dry stirring time results in a more uniform mixture of the resin and the plasticizer. Increasing the kneading temperature improves the fluidity of the plasticizer, which in turn improves the compatibility of the resin and the plasticizer. Increasing the kneading time can result in a more uniform mixture of the resin and the plasticizer. In addition, the amount of functional groups of the polymer also affects the uniformity of absorption of the plasticizer into the polymer. From the above, in the attached examples, in addition to adjusting the compositions of the first polymer film composition and the second polymer film composition, a polymer film having the melt index characteristics required by the present invention is also provided under the conditions of a preheating temperature of 30°C to 45°C, a dry stirring temperature of 30°C to 45°C, a dry stirring time of 2 minutes to 3 minutes, a kneading temperature of 180°C to 210°C, and a kneading time of 8 minutes to 12 minutes.

[0063] The polymer film formed by coextrusion can further form a concave-convex structure on its surface by preheating and mechanical embossing to facilitate degassing. Mechanical embossing refers to a process of forming a texture on the surface of a polymer film using a roller. Examples of mechanical embossing methods include, but are not limited to, an embossing roller method or a calendar roller method. The embossing roller method is preferred. The type of texture formed by mechanical embossing is not particularly limited, and includes a diamond-shaped texture, a linear texture, a sawtooth texture, a square texture, a tapered texture, a circular texture, a subcircle texture, an irregular texture, and the like. The above texture types may be used alone or in combination of two or more. The conditions of preheating and mechanical embossing can be appropriately adjusted according to the composition of the polymer film.

[0064] 2.Laminated glass

[0065] The polymer film of the present invention can be used to manufacture laminated glass. The present invention therefore also provides a laminated glass comprising, in order, a first glass sheet, an intermediate film and a second glass sheet, the intermediate film being the polymer film described above.

[0066] The first glass sheet and the second glass sheet may be the same or different from each other. The first glass sheet and the second glass sheet may be any glass sheet for conventional laminated glass production, independently of each other. Examples of conventional glass sheets for laminated glass production include float glass sheets, tempered glass sheets, wired glass sheets, plain plate glass sheets, etc., but the present invention is not limited thereto. In the attached examples, float glass sheets are used as the first glass sheet and the second glass sheet.

[0067] The laminated glass of the present invention can be produced by any method for producing laminated glass known in the art. In general, the method for producing laminated glass can be roughly divided into a pre-pressing process and an autoclave pressing process. The pre-pressing process is as follows. First, a polymer film is sandwiched between two glass sheets to obtain a laminate. Next, the conveying speed of the belt conveyor of the roller press is set to 2 m / min to 8 m / min, the oven temperature is set to 160°C to 190°C, and the roller pressure is set to 3 kg / cm. 2 ~10kg / cm 2 The laminate is placed on a belt conveyor and passes through an oven and rollers with the distance between the rollers set to 4.5 mm to 6.5 mm in sequence. The laminate pressed by the rollers is then cooled to room temperature, completing the prepress. Next, the prepressed laminate is placed in an autoclave to perform the autoclave pressing process. The autoclave pressing process is a process in which the prepressed laminate is hot pressed under high pressure and high temperature conditions for 100 to 150 minutes to obtain laminated glass. Generally, the high pressure and high temperature conditions refer to a pressure in the range of 10 bar to 15 bar and a temperature in the range of 100°C to 150°C.

[0068] 3. Working Example

[0069] Test Method

[0070] The present invention will be further described below with reference to the following embodiments. The test device and test method are as follows.

[0071] [Measurement of acetalization degree, acetylation degree and hydroxyl group content of polyvinyl acetal]

[0072] The degree of acetalization, the degree of acetylation and the hydroxyl group content of polyvinyl acetal are measured in accordance with JIS K6728:1977.

[0073] [Measurement of molecular weight distribution of polyvinyl acetal]

[0074] The molecular weight distribution of polyvinyl acetal is measured by gel permeation chromatography (GPC). GPC analysis is performed by dissolving polyvinyl acetal in tetrahydrofuran (THF) under the following conditions. The molecular weight (Mn) of polyvinyl acetal is calculated based on the ratio equivalent to the area of ​​standard polystyrene (Water PS STD). Equipment: Waters 1515 PUMP system Detector: Waters 2414 RI Elution conditions: 1.0mL / min, THF Column: Waters Styragel HR5 THF, Waters Styragel HR4 THF, Waters Styragel HR3 THF, Waters Styragel HR1 THF

[0075] [Melt index measurement]

[0076] The melt index of the polymer film is measured according to ASTM D1238 using a melt index tester (model: D4002HV, available from Dynisco). The calculation of the outflow weight is performed according to the manual operation method (method A). The measurement conditions are 190°C, load 2.16 kg, and the polymer film sample weight is 6 g. The detailed measurement steps are as follows. First, the polymer film sample is placed in a constant temperature and humidity chamber at 23°C and 25% relative humidity for 2 hours. Then, the melt index tester is switched on to heat it to 190°C, and the sample is added and packed into a cylindrical barrel. A standard load is applied to the sample in the cylindrical barrel via a piston and a weight (total weight 2.16 kg), and the sample that flows out within 120 seconds is excluded from the calculation. The formal test starts after 120 seconds. The outflow amount of the sample is weighed three times every 200 seconds. The melt index is calculated by the following formula. The unit of melt index is g / 10 min. MI = (total weight of outflow (unit: g)) / (outflow collection time (10 min))

[0077] [Evaluation of continuous layer structure]

[0078] The polymer film is observed using an optical microscope (model: BX51, manufactured by Olympus) to confirm whether the structure of each layer is continuous. The polymer film is cut into a sample of 100 cm x 5 cm (100 cm horizontal length, 5 cm vertical length). Using a clamping jig, the two short sides of the sample are clamped so that the long side of the polymer film (i.e., the cut surface) faces the objective lens. The optical microscope is set as follows, with the objective lens magnification of 5x. The evaluation criteria are as follows. If the structure of each layer of the polymer film is continuous and no discontinuity is observed, the uniformity of the structure is good, and the result is recorded as "○". If discontinuity is observed in any layer of the polymer film, the uniformity of the structure is poor, and the result is recorded as "×".

[0079] [Layer thickness evaluation]

[0080] The thickness of the second layer of the polymer film is measured using an optical microscope (model: BX51, manufactured by Olympus), and the thickness is calculated using the built-in software of the optical microscope (Motic Image Plus 2.0). The polymer film is cut into a sample of 100 cm x 5 cm. Here, 100 cm is the horizontal length and 5 cm is the vertical length. Using a clamping jig, the two short sides of the sample are clamped so that the long side of the polymer film (i.e., the cut surface) faces the objective lens. The optical microscope is set as follows, with the objective lens magnification of 5 times. The measurement method is as follows. The layer thickness is measured at positions 1 cm, 25 cm, 50 cm, 75 cm, and 100 cm from the left boundary, respectively, to obtain five thickness values. The evaluation criteria are as follows. If all five values ​​are within the range of 0.1 mm to 0.15 mm, it is judged to be a good result and recorded as "○". If any of the five values ​​are outside this range, it is deemed unsatisfactory and recorded as an "X." If all five values ​​cannot be measured (i.e., only four values ​​are measured), the result is deemed unsatisfactory and recorded as "NA."

[0081] Additionally, the thickness deviation of the second layer is determined and recorded by subtracting the minimum value from the maximum value of the five values. A deviation of 0.025 mm or less indicates good thickness uniformity. A deviation of more than 0.025 mm indicates poor thickness uniformity. If the five values ​​cannot be measured, the thickness deviation of the second layer is recorded as "NA (Not Applicable)".

[0082] [Evaluation of loss factor]

[0083] The loss factor of the laminated glass is evaluated according to ISO 16940:2008, Measurement of Mechanical Impedance (MIM). The sample is prepared as follows. First, a polymer film with a length of 300 mm and a width of 25 mm is sandwiched between two float glass sheets (length: 300 mm, width: 25 mm, thickness: 2 mm) to obtain a laminate. This laminate is subjected to a pre-pressing process and an autoclave pressing process to obtain a laminated glass. The pre-pressing process and the autoclave pressing process are as described above. Next, this laminated glass is placed in a thermo-hygrostat at 23°C and a relative humidity of 55% for 2 hours. After that, the loss factor test is performed as follows. First, the center of the laminated glass is fixed to a vibration exciter, and the laminated glass is vibrated at an ambient temperature of 20°C. Next, the force and frequency of vibrating the laminated glass are measured using an impedance head, and the obtained value is converted into a damping loss factor by an analysis system. The calculation is performed according to the first vibration mode using the half-power method. If the attenuation loss coefficient of the laminated glass at 20°C is 0.25 or more, good sound insulation performance is obtained.

[0084] [Evaluation of optical distortion]

[0085] First, prepare a 30cm x 30cm laminated glass as a test sample, a projector (model: NP-P451X, manufactured by NEC, light source: 4500 ANSI lumens), a sample holder, and a white screen. Install the projector, sample holder, and white screen in a darkroom, place the sample holder between the projector and the white screen, and set the distance between the projector and the sample holder and the distance between the sample holder and the white screen to 1.5m. Place the test sample on the sample holder and adjust the angle so that the test sample is tilted 15° toward the projector with respect to an axis perpendicular to the ground. Turn on the projector's light source so that the projected light passes through the test sample and is projected onto the white screen. Visually observe the white screen to confirm that the difference between light and dark is not significant. If there are no filamentous stripes (optical ripples) on the laminated glass, it is recorded as "none", and if there are filamentous stripes (optical ripples) on the laminated glass, it is recorded as "present".

[0086] 3.2. Polymer film production and physical property measurement

[0087] 3.2.1. First and third layers of polymer film

[0088] 100 parts by weight of poly(vinyl butyral) (PVB, manufactured by Chang Chun Petrochemical Co., Ltd.) was preheated in an oven at 30°C to 45°C for 1 minute. Next, the preheated PVB and the plasticizer were dry-stirred at a first dry-stirring temperature and a first dry-stirring time to obtain a first dry-stirring mixture. Then, the first dry-stirring mixture was kneaded at a first kneading temperature and a first kneading time using a twin-screw kneader to obtain first polymer film compositions of Examples 1 to 11 and Comparative Examples 1 to 9, respectively. The blending amount of the plasticizer is shown in Tables 1-1 and 2-1, and the first dry-stirring temperature, the first dry-stirring time, the first kneading temperature, and the first kneading time are shown in Tables 1-2 and 2-2. The physical properties of the PVB (Mn, acetalization degree, acetylation degree, hydroxyl group content) were measured according to the above-mentioned test methods, and the results are shown in Tables 1-1 and 2-1. The unit for the degree of acetalization, the degree of acetylation, and the hydroxyl group content is all mol %.

[0089] The first polymer film compositions of Examples 1 to 11 and Comparative Examples 1 to 9 were each placed in an extruder to obtain a monolayer polymer film (hereinafter referred to as "first monolayer polymer film"). The melt index of the first monolayer polymer film was measured according to the above-mentioned test method, and the results are shown in Tables 1-5 and 2-5. Each of the first polymer film compositions was used as the material for the first layer and the third layer of the polymer film of Examples 1 to 11 and Comparative Examples 1 to 9 described below. Therefore, the melt index of each of the first monolayer polymer films represents the melt index of each of the first layer and the third layer of the polymer film, i.e., the first melt index and the third melt index. Since the third melt index is the same as the first melt index, only the result of the first melt index is listed in the table.

[0090] 3.2.2. Second layer of polymer film

[0091] 100 parts by weight of poly(vinyl butyral) (PVB, manufactured by Chang Chun Petrochemical Co., Ltd.) was preheated in an oven at 30°C to 45°C for 1 minute. Next, the preheated PVB and the plasticizer were dry-stirred at a second dry-stirring temperature for a second dry-stirring time to obtain a second dry-stirring mixture. Then, the second dry-stirring mixture was kneaded at a second kneading temperature for a second kneading time using a twin-screw kneader to obtain second polymer film compositions of Examples 1 to 11 and Comparative Examples 1 to 9, respectively. The blending amount of the plasticizer is shown in Tables 1-3 and 2-3, and the second dry-stirring temperature, second dry-stirring time, second kneading temperature, and second kneading time are shown in Tables 1-4 and 2-4. The physical properties of PVB (Mn, acetalization degree, acetylation degree, hydroxyl group content) were measured according to the above-mentioned test methods, and the results are shown in Tables 1-3 and 2-3. The unit for the degree of acetalization, the degree of acetylation, and the hydroxyl group content is all mol %.

[0092] The second polymer film compositions of Examples 1 to 11 and Comparative Examples 1 to 9 were each placed in an extruder to obtain a monolayer polymer film (hereinafter referred to as "second monolayer polymer film"). The melt index of each of the second monolayer polymer films was measured according to the above-mentioned test method, and the results are shown in Tables 1-5 and 2-5. Each of the second polymer film compositions was used as the material of the second layer of the polymer film of Examples 1 to 11 and Comparative Examples 1 to 9 described below, and the melt index of each of the second monolayer polymer films represents the melt index of the second layer of the polymer film, i.e., the second melt index.

[0093] 3.2.3. Polymer film production

[0094] The first polymer film composition of Examples 1 to 11 and Comparative Examples 1 to 9, and the second polymer film composition of Examples 1 to 11 and Comparative Examples 1 to 9 were each placed in a co-extruder to form a three-layer polymer film by co-extrusion. The total thickness of the polymer film was 0.8 mm, the first layer and the third layer were formed from the first polymer film composition, and each of the first layer and the third layer had a thickness of 0.335 mm. The second layer was formed from the second polymer film composition, and the second layer had a thickness of 0.13 mm.

[0095] Thereafter, the two surfaces of the polymer film were preheated and mechanically embossed to form a texture, thereby obtaining the polymer films of Examples 1-11 and Comparative Examples 1-9.

[0096] [Table 1-1]

[0097] [Table 1-2]

[0098] [Table 1-3]

[0099] [Table 1-4]

[0100] [Table 1-5]

[0101] [Table 2-1]

[0102] [Table 2-2]

[0103] [Table 2-3]

[0104] [Table 2-4]

[0105] [Table 2-5]

[0106] 3.3. Manufacturing of laminated glass and evaluation of its physical properties

[0107] Laminated glass was produced using each of the polymer films of Examples 1 to 11 and Comparative Examples 1 to 9. First, the polymer film was cut to 300 mm x 300 mm. Next, for each polymer film, two clean and transparent float glass sheets (length: 300 mm, width: 300 mm, thickness: 2 mm) were prepared. The cut polymer films of Examples 1 to 11 and Comparative Examples 1 to 9 were each sandwiched between two transparent float glass sheets to obtain a laminate. This laminate was pre-pressed by vacuum drawing using nip rollers. Pre-pressing with nip rollers was performed as follows. The conveying speed of the belt conveyor of the roller press was 4.5 m / min, the oven temperature was 180°C, and the roller pressure was 3 kg / cm. 2 The laminate was placed on a belt conveyor and passed through an oven and rollers in that order. The distance between the rollers was 5 mm. The pre-pressed laminate was then placed in an autoclave and hot pressed at a pressure of 13 bar and a temperature of 135°C for 120 minutes, and then cooled to room temperature to obtain a laminated glass.

[0108] The polymer films and laminated glasses of Examples 1 to 11 and Comparative Examples 1 to 9 were evaluated for the continuous layer structure, layer thickness, loss factor, and optical distortion according to the above-mentioned test methods. The results are shown in Tables 3-1 and 3-2.

[0109] [Table 3-1]

[0110] [Table 3-2]

[0111] As shown in Table 3-1, Examples 1 to 11 show that the polymer film of the present invention has a continuous layer structure, good structural uniformity, and a suitable and uniform thickness of the second layer. In particular, the laminated glass made from the polymer film of the present invention has a loss factor of more than 0.25 and shows good sound insulation effect. Meanwhile, the laminated glass made from the polymer film of the present invention does not show optical distortion defects.

[0112] In contrast, as shown in Table 3-2, the polymer films not according to the present invention lack a continuous layer structure and show an inappropriate and non-uniform thickness of the second layer. The laminated glass produced from these polymer films has a loss factor lower than 0.25, indicating a poor sound insulation effect. In addition, the laminated glass produced from these polymer films has optical distortion defects. In particular, Comparative Example 1 shows that when the first melt index is larger than the second melt index and the difference between the second melt index and the first melt index is out of the set range, the polymer film cannot obtain a continuous second layer of appropriate thickness, and as a result, the laminated glass has a loss factor lower than 0.25 and optical distortion defects. Comparative Examples 2, 3 and 6 show that when the difference between the second melt index and the first melt index is smaller than the set range of the present invention, the loss factor of the laminated glass is smaller than 0.25, indicating a poor sound insulation effect. Comparative Examples 4, 5 and 8 show that when the difference between the second melt index and the first melt index is greater than the set range of the present invention, the thickness of the second layer of the polymer film is insufficient and non-uniform, resulting in a laminated glass with a loss factor lower than 0.25 and optical distortion. Comparative Example 7 shows that when the second melt index is greater than the set range, even if the difference between the second melt index and the first melt index is within the set range, the thickness of the second layer of the polymer film is insufficient and non-uniform, resulting in a laminated glass with a loss factor lower than 0.25 and optical distortion. Comparative Example 9 shows that when the second melt index is lower than the set range, even if the difference between the second melt index and the first melt index is within the set range, the laminated glass produced has a loss factor lower than 0.25 and poor sound insulation effect.

[0113] The above examples are used to explain the principle and effectiveness of the present invention and to demonstrate its inventive features, but are not used to limit the scope of the present invention. Those skilled in the art can proceed with various modifications and substitutions based on the disclosure and suggestions of the present invention described. Therefore, the protection scope of the present invention is as defined in the appended claims.

[0114] (Additional Note) (Appendix 1) A thermoplastic elastomer comprising a first layer, a second layer and a third layer in this order, two surfaces of the second layer being in contact with the first layer and the third layer, respectively, the first layer having a first melt index, the second layer having a second melt index, and the third layer having a third melt index, the second melt index being in the range of 3.5 g / 10 min to 10.0 g / 10 min, the first melt index and the third melt index being each independently lower than 3.5 g / 10 min, and the difference between the second melt index and the first melt index and the difference between the second melt index and the third melt index being independently in the range of 0.2 g / 10 min to 8.5 g / 10 min. A polymer film characterized in that

[0115] (Appendix 2) the first melt index and the third melt index are each independently in the range of 1.5 g / 10 min to 3.3 g / 10 min; 2. The polymer film according to claim 1 .

[0116] (Appendix 3) The first melt index, the second melt index, and the third melt index are measured according to ASTM D1238 at 190° C. and under a load of 2.16 kg; 2. The polymer film according to claim 1 .

[0117] (Appendix 4) the first layer, the second layer, and the third layer each independently comprise a polyvinyl acetal; 4. The polymer film according to claim 1,

[0118] (Appendix 5) the first layer, the second layer, and the third layer each independently comprise poly(vinyl butyral); 5. The polymer film according to claim 4,

[0119] (Appendix 6) The polyvinyl acetal contained in the second layer has a degree of acetalization in the range of 56 mol% to 74 mol%, a degree of acetylation in the range of 5 mol% to 15 mol%, and a hydroxyl group content in the range of 20 mol% to 30 mol%. 5. The polymer film according to claim 4,

[0120] (Appendix 7) the polyvinyl acetal contained in the first layer and the polyvinyl acetal contained in the third layer each independently have a degree of acetalization in the range of 60 mol% to 75 mol%, a degree of acetylation in the range of 0.1 mol% to 5 mol%, and a hydroxyl group content in the range of 20 mol% to 35 mol%; 5. The polymer film according to claim 4,

[0121] (Appendix 8) The number average molecular weight (Mn) of the polyvinyl acetal contained in the second layer is in the range of 100,000 to 240,000. 5. The polymer film according to claim 4,

[0122] (Appendix 9) the number average molecular weight (Mn) of the polyvinyl acetal contained in the first layer and the number average molecular weight (Mn) of the polyvinyl acetal contained in the third layer are each independently in the range of 90,000 to 120,000; 5. The polymer film according to claim 4,

[0123] (Appendix 10) the first layer, the second layer, and the third layer each independently further comprise a plasticizer; 5. The polymer film according to claim 4,

[0124] (Appendix 11) the amount of plasticizer contained in the first layer is in the range of 30 parts by weight to 50 parts by weight based on 100 parts by weight of the polyvinyl acetal contained in the first layer; the amount of plasticizer contained in the second layer is in the range of 55 parts by weight to 85 parts by weight based on 100 parts by weight of the polyvinyl acetal contained in the second layer, the amount of plasticizer contained in the third layer is in the range of 30 parts by weight to 50 parts by weight based on 100 parts by weight of the polyvinyl acetal contained in the third layer; 11. The polymer film according to claim 10,

[0125] (Appendix 12) The glass sheet includes, in order, a first glass sheet, an intermediate film, and a second glass sheet; The intermediate film is a polymer film according to any one of claims 1 to 3; The laminated glass is characterized by the above-mentioned.

Claims

1. a first layer, a second layer and a third layer, in that order, two surfaces of the second layer being in contact with the first layer and the third layer, respectively, the first layer having a first melt index, the second layer having a second melt index and the third layer having a third melt index, the second melt index being in the range of 3.5 g / 10 min to 10.0 g / 10 min, the first melt index and the third melt index being each independently lower than 3.5 g / 10 min, and the difference between the second melt index and the first melt index and the difference between the second melt index and the third melt index being independently in the range of 0.2 g / 10 min to 8.5 g / 10 min; the first layer, the second layer, and the third layer each independently comprise a polyvinyl acetal and a plasticizer; the amount of plasticizer contained in the first layer is in the range of 30 parts by weight to 50 parts by weight based on 100 parts by weight of the polyvinyl acetal contained in the first layer; the amount of plasticizer contained in the second layer is in the range of 55 parts by weight to 85 parts by weight based on 100 parts by weight of the polyvinyl acetal contained in the second layer; the amount of plasticizer contained in the third layer is in the range of 30 parts by weight to 50 parts by weight based on 100 parts by weight of the polyvinyl acetal contained in the third layer; the thickness of the first layer and the third layer are each independently in the range of 250 μm to 450 μm, and the thickness of the second layer is in the range of 50 μm to 250 μm; A polymer film characterized in that

2. the first melt index and the third melt index are each independently in the range of 1.5 g / 10 min to 3.3 g / 10 min; 2. The polymer film of claim 1.

3. the first melt index, the second melt index and the third melt index are measured according to ASTM D1238 at 190° C. and under a load of 2.16 kg; 2. The polymer film of claim 1.

4. the first layer, the second layer, and the third layer each independently comprise poly(vinyl butyral); 4. The polymer film according to claim 1 .

5. The polyvinyl acetal contained in the second layer has an acetalization degree in the range of 56 mol% to 74 mol%, an acetylation degree in the range of 5 mol% to 15 mol%, and a hydroxyl group content in the range of 20 mol% to 30 mol%.

4. The polymer film according to claim 1 .

6. the polyvinyl acetal contained in the first layer and the polyvinyl acetal contained in the third layer each independently have an acetalization degree in the range of 60 mol% to 75 mol%, an acetylation degree in the range of 0.1 mol% to 5 mol%, and a hydroxyl group content in the range of 20 mol% to 35 mol%; 4. The polymer film according to claim 1 .

7. The number average molecular weight (Mn) of the polyvinyl acetal contained in the second layer is in the range of 100,000 to 240,000.

4. The polymer film according to claim 1 .

8. the number average molecular weight (Mn) of the polyvinyl acetal contained in the first layer and the number average molecular weight (Mn) of the polyvinyl acetal contained in the third layer are each independently in the range of 90,000 to 120,000; 4. The polymer film according to claim 1 .

9. The glass sheet includes, in order, a first glass sheet, an intermediate film, and a second glass sheet; The intermediate film is a polymer film according to any one of claims 1 to 3. The laminated glass is characterized by the above-mentioned.

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