Polymer films and their applications

Abstract

The present invention provides a polymer film, which includes a first part and a second part laminated with the first part, wherein the first part and the second part are each independently composed of one or more layers, wherein: each layer of the first part independently has a melt index of 3.5 g / 10 min to 10.0 g / 10 min, and each layer of the second part independently has a melt index of less than 3.5 g / 10 min; each layer of the first part independently has a product of its melt index and the thickness ratio of its share to the total thickness of the first part and the second part, provided that the sum of the products of each layer of the first part is 0.39 g / 10 min to 2.50 g / 10 min; and each layer of the second part independently has a product of its melt index and the thickness ratio of its share to the total thickness of the first part and the second part, provided that the sum of the products of each layer of the second part is 1.10 g / 10 min to 2.95 g / 10 min.

Description

Technical Field

[0001] The present invention relates to a polymer film, and more particularly to a multilayer polymer film having characteristics related to the product of melt index (MI) and thickness ratio. The present invention also relates to a laminated glass prepared using the polymer film. Background Art

[0002] Laminated glass is a composite glass material made by sandwiching a polymer film between two sheets of glass. The glass sheets and the polymer film are tightly bonded together through heat pressing. Laminated glass is widely used in the automotive and construction industries due to its excellent impact resistance and safety.

[0003] To enhance the sound insulation of laminated glass, it is known to use a multi-layered polymer film as the interlayer. This polymer film comprises two outer layers and an inner layer positioned between them. By increasing the thickness of the inner layer and adjusting its viscoelastic properties, the sound damping effect is enhanced, thereby achieving sound insulation. However, existing laminated glass cannot simultaneously achieve good safety, optical properties, and sound insulation performance. Summary of the Invention

[0004] In light of this, the present invention provides a polymer film comprising a first part and a second part. Research has found that by controlling the melt index of each layer of the first and second parts, and the product of the melt index and its thickness ratio, within specific ranges, the polymer film can achieve excellent structural uniformity and produce laminated glass with excellent sound insulation, optical properties, and safety (high mechanical strength). Therefore, the present invention is particularly suitable for the production of soundproof laminated glass.

[0005] Therefore, an object of the present invention is to provide a polymer film comprising a first part and a second part laminated with the first part, wherein the first part and the second part are each independently composed of one or more layers, wherein:

[0006] Each layer of the first portion independently has a melt index of 3.5 g / 10 min to 10.0 g / 10 min, and each layer of the second portion independently has a melt index of less than 3.5 g / 10 min;

[0007] Each layer of the first part independently has a product of its melt index and its thickness ratio to the total thickness of the first part and the second part, provided that the sum of the products of the layers of the first part is from 0.39 g / 10 min to 2.50 g / 10 min; and

[0008] Each layer of the second part independently has a product of its melt index and its thickness ratio to the total thickness of the first part and the second part, provided that the sum of the products of the layers of the second part is 1.10 g / 10 min to 2.95 g / 10 min.

[0009] In some embodiments of the present invention, the melt index of each layer of the second part is independently 1.5 g / 10 min to 3.3 g / 10 min.

[0010] In some embodiments of the present invention, the melt index is measured according to ASTM D1238 at 190° C. and a load of 2.16 kg.

[0011] In some embodiments of the present invention, each layer of the first portion and each layer of the second portion independently comprises polyvinyl acetal, and the polyvinyl acetal can be selected from the group consisting of polyvinyl formal, polyvinyl acetal, polyvinyl butyral, polyvinyl valeral, polyvinyl hexyl acetal, and combinations thereof. In a preferred embodiment of the present invention, each layer of the first portion and each layer of the second portion independently comprises polyvinyl butyral.

[0012] In some embodiments of the present invention, each layer of the first part independently contains polyvinyl acetal having the following properties: 56 mol% to 74 mol% acetalization degree, 5 mol% to 15 mol% acetylation degree, and 20 mol% to 30 mol% hydroxyl content.

[0013] In some embodiments of the present invention, each layer of the second part independently contains polyvinyl acetal having the following properties: 60 mol% to 75 mol% acetalization degree, 0.1 mol% to 5 mol% acetylation degree, and 20 mol% to 35 mol% hydroxyl content.

[0014] In some embodiments of the present invention, the number average molecular weight (Mn) of the polyvinyl acetal contained in each layer of the first part is independently 100,000 to 240,000.

[0015] In some embodiments of the present invention, the number average molecular weight (Mn) of the polyvinyl acetal included in each layer of the second part is independently 90,000 to 120,000.

[0016] In some embodiments of the present invention, each layer of the first part and each layer of the second part independently further contain a plasticizer.

[0017] In some embodiments of the present invention, each layer of the first part and each layer of the second part further independently contain a plasticizer. In each layer of the first part, the content of the plasticizer in each layer is independently 55 to 85 parts by weight, based on 100 parts by weight of the polyvinyl acetal contained in each layer; and in each layer of the second part, the content of the plasticizer in each layer is independently 30 to 50 parts by weight, based on 100 parts by weight of the polyvinyl acetal contained in each layer.

[0018] In some embodiments of the present invention, each layer of the first portion constitutes M first sub-portions, each layer of the second portion constitutes N second sub-portions, and the second sub-portions and the first sub-portions are arranged alternately, wherein M and N are each independently a positive integer.

[0019] In some embodiments of the present invention, N is M+1.

[0020] Another object of the present invention is to provide a laminated glass comprising a first glass sheet, an intermediate film, and a second glass sheet in sequence, wherein the intermediate film is the polymer film as described above.

[0021] In order to make the above-mentioned objectives, technical features and advantages of the present invention more obvious and easy to understand, some specific implementation plans are described in detail below. DETAILED DESCRIPTION

[0022] Some specific embodiments of the present invention will be described in detail below; however, the present invention can be practiced in a variety of different forms of embodiments, and the scope of protection of the present invention should not be limited to the specific embodiments.

[0023] Unless otherwise stated, the terms “a”, “an”, “the” and similar terms used in this specification and the claims should be understood to include both the singular and the plural.

[0024] Unless otherwise specified, the terms “first,” “second,” and the like used in this specification and the claims are merely used to distinguish between described elements or components and have no special meanings and are not used to represent a sequential order.

[0025] In this specification and claims, "melt index (MI)" is measured according to ASTM D1238 at 190°C and a load of 2.16 kg.

[0026] In this specification and claims, the unit of number average molecular weight (Mn) is "Dalton".

[0027] Throughout this specification and claims, "thickness ratio" refers to the ratio of the thickness of a single layer to the total thickness of a polymer film. For example, if a polymer film has a five-layer structure with a total thickness of 2 mm, wherein the first portion comprises three 0.5 mm layers and the second portion comprises two 0.25 mm layers, then the thickness ratio of the layers in the first portion is 0.25, and the thickness ratio of the layers in the second portion is 0.125.

[0028] In this specification and claims, the sum of the products of thickness ratio and melt index refers to the sum of the products of the thickness ratio and melt index of each layer. For example, if the first portion of the polymer film has three layers, the thickness ratios of the layers are 0.1, 0.2, and 0.3, respectively, and the melt indexes are 3.5 g / 10 min, 4 g / 10 min, and 5 g / 10 min, respectively, then the sum of the products of the thickness ratio and melt index of the layers in the first portion is (0.1 × 3.5) + (0.2 × 4) + (0.3 × 4.5) = 2.5.

[0029] The present invention offers advantages over existing technologies in that the provided polymer film can be used to prepare laminated glass that combines excellent sound insulation, excellent optical properties, and excellent safety (high mechanical strength). The following provides a detailed description of the present polymer film and its related applications.

[0030] 1. Polymer film

[0031] 1.1. Properties of polymer films

[0032] The polymer film of the present invention includes a first part and a second part, and the first part and the second part are each independently composed of one or more layers and have the following properties.

[0033] Each layer of the first part independently has a melt index of 3.5 g / 10 minutes to 10.0 g / 10 minutes, for example, 3.5 g / 10 minutes, 3.6 g / 10 minutes, 3.7 g / 10 minutes, 3.8 g / 10 minutes, 3.9 g / 10 minutes, 4.0 g / 10 minutes, 4.1 g / 10 minutes, 4.2 g / 10 minutes, 4.3 g / 10 minutes, 4.4 g / 10 minutes, 4.5 g / 10 minutes, 4.6 g / 10 minutes, 4.7 g / 10 minutes, 4.8 g / 10 minutes , 4.9 g / 10 minutes, 5.0 g / 10 minutes, 5.1 g / 10 minutes, 5.2 g / 10 minutes, 5.3 g / 10 minutes, 5.4 g / 10 minutes, 5.5 g / 10 minutes, 5.6 g / 10 minutes, 5.7 g / 10 minutes, 5.8 g / 10 minutes, 5.9 g / 10 minutes, 6.0 g / 10 minutes, 6.1 g / 10 minutes, 6.2 g / 10 minutes, 6.3 g / 10 minutes, 6.4 g / 10 minutes, 6.5 g / 10 minutes, 6.6 g / 10 minutes , 6.7 g / 10 minutes, 6.8 g / 10 minutes, 6.9 g / 10 minutes, 7.0 g / 10 minutes, 7.1 g / 10 minutes, 7.2 g / 10 minutes, 7.3 g / 10 minutes, 7.4 g / 10 minutes, 7.5 g / 10 minutes, 7.6 g / 10 minutes, 7.7 g / 10 minutes, 7.8 g / 10 minutes, 7.9 g / 10 minutes, 8.0 g / 10 minutes, 8.1 g / 10 minutes, 8.2 g / 10 minutes, 8.3 g / 10 minutes, 8.4 g / 10 minutes , 8.5 g / 10 min, 8.6 g / 10 min, 8.7 g / 10 min, 8.8 g / 10 min, 8.9 g / 10 min, 9.0 g / 10 min, 9.1 g / 10 min, 9.2 g / 10 min, 9.3 g / 10 min, 9.4 g / 10 min, 9.5 g / 10 min, 9.6 g / 10 min, 9.7 g / 10 min, 9.8 g / 10 min, 9.9 g / 10 min, or 10.0 g / 10 min, or a range between any two of the foregoing values. The first portion having the above melt index can reduce sonic oscillations and optimize sound insulation.

[0034] Each layer of the second portion independently has a melt index of less than 3.5 g / 10 min, for example, a melt index of 1.5 g / 10 min to 3.3 g / 10 min, for example, 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 a range consisting of any two of the foregoing values.

[0035] Each layer of the first part independently has a product of its melt index and its thickness ratio to the total thickness of the first part and the second part (i.e., melt index×thickness ratio), and the sum of the products of the layers of the first part is 0.39 g / 10 min to 2.50 g / 10 min, for example, 0.39 g / 10 min, 0.40 g / 10 min, 0.45 g / 10 min, 0.50 g / 10 min, 0.55 g / 10 min, 0 min, 0.60 g / 10 min, 0.65 g / 10 min, 0.70 g / 10 min, 0.75 g / 10 min, 0.80 g / 10 min, 0.85 g / 10 min, 0.90 g / 10 min, 0.95 g / 10 min, 1.00 g / 10 min, 1.05 g / 10 min, 1.10 g / 10 min, 1.15 g / 10 min, 1.20 g / 10 min, 1.25 g / 10 minutes, 1.30 g / 10 minutes, 1.35 g / 10 minutes, 1.40 g / 10 minutes, 1.45 g / 10 minutes, 1.50 g / 10 minutes, 1.55 g / 10 minutes, 1.60 g / 10 minutes, 1.65 g / 10 minutes, 1.70 g / 10 minutes, 1.75 g / 10 minutes, 1.80 g / 10 minutes, 1.85 g / 10 minutes, 1.90 g / 10 minutes, 1.95 g / 10 min, 2.00 g / 10 min, 2.05 g / 10 min, 2.10 g / 10 min, 2.15 g / 10 min, 2.20 g / 10 min, 2.25 g / 10 min, 2.30 g / 10 min, 2.35 g / 10 min, 2.40 g / 10 min, 2.45 g / 10 min, or 2.50 g / 10 min, or within the range consisting of any two of the above values.

[0036] Each layer of the second part independently has a product of its melt index and the thickness ratio of its share of the total thickness of the first part and the second part (i.e., melt index×thickness ratio), and the sum of the products of the layers of the second part is 1.10 g / 10 minutes to 2.95 g / 10 minutes, for example, 1.10 g / 10 minutes, 1.15 g / 10 minutes, 1.20 g / 10 minutes, 1.25 g / 10 minutes, 1.30 g / 10 minutes, 1.35 g / 10 minutes, 1.40 g / 10 minutes, 1.45 g / 10 minutes, 1.50 g / 10 minutes, 1.55 g / 10 minutes, 1.60 g / 10 minutes, 1.65 g / 10 minutes, 1.70 g / 10 minutes, 1.75 g / 10 minutes, 1.80 g / 10 minutes, 1.86 g / 10 minutes, 1.90 g / 10 minutes, 2.95 g / 10 minutes, 3.97 g / 10 minutes, 4.11 g / 10 minutes, 5.12 g / 10 minutes, 6.13 g / 10 minutes, 7.14 g / 10 minutes, 8.15 g / 10 minutes, 9.16 g / 10 minutes, 10.17 g / 10 minutes, 11.18 g / 10 minutes, 12.19 g / 10 minutes, 13.20 g / 10 minutes, 13.21 g / 10 minutes, 13.22 g / 10 minutes, 13.23 g / 10 minutes, 13.24 g / 10 minutes, 13.25 g / 10 minutes g / 10 minutes, 2.5 g / 10 minutes, 2.6 g / 10 minutes, 2.7 g / 10 minutes, 2.8 g / 10 minutes, 2.9 g / 10 minutes, or 2.95 g / 10 minutes, or within a range consisting of any two of the above values.

[0037] Research has found that only when the melt index of each layer of the first part and the second part meets the above-specified range, and the sum of the products of the melt index and thickness ratio of the first part and the second part meets the above-specified range, can the polymer film provide laminated glass with excellent sound insulation effect, excellent optical properties and excellent safety (high mechanical strength).

[0038] 1.2. Structure of polymer membranes

[0039] The polymer film of the present invention comprises a first portion and a second portion, wherein the first portion and the second portion are each independently composed of one or more layers. Alternatively, the polymer film of the present invention consists essentially of the first portion and the second portion, wherein the first portion and the second portion are each independently composed of one or more layers. Alternatively, the polymer film of the present invention consists of the first portion and the second portion, wherein the first portion and the second portion are each independently composed of one or more layers.

[0040] In the polymer film of the present invention, the first part and the second part are laminated. Lamination of the first part and the second part means that the layers of the first part and the second part are stacked together in any arrangement. For example, when the first part is composed of two layers of layer A and the second part is composed of three layers of layer B, the stacking arrangement of the layers of the first part and the second part includes, but is not limited to, the following: AABBB, ABABB, ABBAB, ABBBA, BABAB, or BBAAB.

[0041] In some embodiments of the present invention, each layer of the first portion constitutes M first sub-portions, and each layer of the second portion constitutes N second sub-portions, and the second sub-portions are arranged alternately with the first sub-portions, wherein each of the first sub-portions and the second sub-portions can independently include one or more layers, and M and N can independently be positive integers, for example, can independently be integers from 1 to 5. For example, when M is 2 and N is 2, the polymer film is composed of the first sub-portion, the second sub-portion, the first sub-portion, and the second sub-portion in sequence. When M is 2 and N is 3, the polymer film is composed of the second sub-portion, the first sub-portion, the second sub-portion, the first sub-portion, and the second sub-portion in sequence. When M is 3 and N is 2, the polymer film is composed of the first sub-portion, the second sub-portion, the first sub-portion, the second sub-portion, and the first sub-portion in sequence. In a preferred embodiment of the present invention, N is M+1. In a more preferred embodiment of the present invention, M is 1 or 2, and N is M+1.

[0042] 1.3. Composition of polymer films

[0043] In the polymer film of the present invention, each layer of the first portion and each layer of the second portion independently contains polyvinyl acetal as an essential component, and each layer of the first portion and each layer of the second portion independently may further contain other optional components, such as a plasticizer or other conventional additives. Herein, "each layer of the first portion and each layer of the second portion independently contains polyvinyl acetal" means that each layer of the first portion and each layer of the second portion each contains polyvinyl acetal, and the polyvinyl acetal contained in each layer may be the same or different. In some embodiments of the present invention, each layer of the first portion and each layer of the second portion independently contains polyvinyl acetal and a plasticizer, wherein the polyvinyl acetal and plasticizer contained in each layer may be the same or different. Alternatively, each layer of the first portion and each layer of the second portion independently consists essentially of polyvinyl acetal and a plasticizer, wherein the polyvinyl acetal and plasticizer contained in each layer may be the same or different. Alternatively, each layer of the first portion and each layer of the second portion are independently composed of polyvinyl acetal and a plasticizer, wherein the polyvinyl acetal and the plasticizer included in each layer may be the same or different.

[0044] 1.3.1. Polyvinyl acetal

[0045] Examples of polyvinyl acetals include, but are not limited to, polyvinyl formal, polyvinyl acetal, polyvinyl butyral, polyvinyl valeral, and polyvinyl hexyl acetal. Each of the aforementioned polyvinyl acetals may be used alone or in combination. In a preferred embodiment of the present invention, the polyvinyl acetal is polyvinyl butyral.

[0046] 1.3.1.1. Polyvinyl acetals included in Part 1

[0047] In some embodiments of the present invention, the number average molecular weight (Mn) of the polyvinyl acetal contained in each layer of the first part is independently 100,000 to 240,000, for example, 100,000, 105,000, 110,000, 115,000, 120,000, 125,000, 130,000, 135,000, 140,000, 145,000, 150,000, 15 The number average molecular weight of a polymer is 5,000, 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 consisting of any two of the foregoing values. A higher number average molecular weight of a polymer indicates a higher degree of polymerization, and correspondingly, poorer fluidity and a lower melt index. Conversely, a lower number average molecular weight of a polymer indicates a higher melt index.

[0048] In some embodiments of the present invention, the acetal group content (i.e., degree of acetalization) of the polyvinyl acetal contained in each layer of the first part may be independently 56 mol% to 74 mol%, for example, 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%, 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%, 100 mol%, 101 mol%, 102 mol%, 103 mol%, 104 mol%, 105 mol%, 106 mol%, 107 mol%, 108 mol%, 109 mol%, 110 mol%, 111 mol%, 112 mol%, 113 mol%, 114 mol%, 115 %, 62.5 mol%, 63 mol%, 63.5 mol%, 64 mol%, 64.5 mol%, 65 mol%, 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%, or 74 mol%, or a range consisting of any two of the foregoing values. In a preferred embodiment of the present invention, the degree of acetalization of the polyvinyl acetal contained in each layer of the first part is independently 60 mol% to 71 mol%, based on the total moles of acetal groups, acetyl groups, and hydroxyl groups of the polyvinyl acetal contained in each layer of the first part.

[0049] In some embodiments of the present invention, the acetyl content (i.e., degree of acetylation) of the polyvinyl acetal contained in each layer of the first part may be independently 5 mol% to 15 mol%, for example, 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%, based on the total moles of acetal groups, acetyl groups, and hydroxyl groups of the polyvinyl acetal contained in each layer of the first part, or a range between any two of the foregoing values. In a preferred embodiment of the present invention, the degree of acetylation of the polyvinyl acetal contained in each layer of the first part is independently 7 mol % to 12 mol %, based on the total molar number of acetal groups, acetyl groups, and hydroxyl groups of the polyvinyl acetal included in each layer of the first part.

[0050] In some embodiments of the present invention, the hydroxyl group content of the polyvinyl acetal contained in each layer of the first part may be independently 20 mol% to 30 mol%, for example, 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%, based on the total moles of acetal groups, acetyl groups, and hydroxyl groups of the polyvinyl acetal contained in each layer of the first part, or a range between any two of the foregoing values. In a preferred embodiment of the present invention, the hydroxyl content of each polyvinyl acetal layer in the first portion is independently 22 mol% to 28 mol%, based on the total molar amount of acetal groups, acetyl groups, and hydroxyl groups in each layer of the first portion. A lower hydroxyl content indicates a higher plasticizer content that the polyvinyl acetal can absorb.

[0051] 1.3.1.2. Polyvinyl acetal contained in the second part

[0052] In some embodiments of the present invention, the number average molecular weight (Mn) of the polyvinyl acetal contained in each layer of the second part is independently 90,000 to 120,000, for example, 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, 110,000, 111,000, 112,000, 113,000, 114,000, 115,000, 116,000 19,000, or 120,000, or a range between any two of the foregoing values.

[0053] In some embodiments of the present invention, based on the total molar number of acetal groups, acetyl groups, and hydroxyl groups of the polyvinyl acetal contained in each layer of the second part, the acetal group content (i.e., degree of acetalization) of the polyvinyl acetal contained in each layer of the second part may be independently 60 mol% to 75 mol%, for example, 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%, 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%, 100 mol%, 101 mol%, 102 mol%, 103 mol%, 104 mol%, 105 mol%, 106 mol%, 107 mol%, 108 mol%, 109 mol%, 110 mol%, 111 %, 65 mol%, 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 consisting of any two of the foregoing values. In a preferred embodiment of the present invention, the degree of acetalization of the polyvinyl acetal contained in each layer of the second portion is independently 70 mol% to 72 mol%, based on the total molar number of acetal groups, acetyl groups, and hydroxyl groups of the polyvinyl acetal contained in each layer of the second portion.

[0054] In some embodiments of the present invention, the acetyl content (i.e., degree of acetylation) of the polyvinyl acetal contained in each layer of the second portion may be independently 0.1 mol% to 5 mol%, for example, 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%, based on the total molar number of acetal groups, acetyl groups, and hydroxyl groups in the polyvinyl acetal contained in each layer of the second portion, or a range comprised of any two of the foregoing values. In a preferred embodiment of the present invention, the degree of acetylation of the polyvinyl acetal contained in each layer of the second portion is independently 0.5 mol% to 1.5 mol%, based on the total molar number of acetal groups, acetyl groups, and hydroxyl groups in the polyvinyl acetal contained in each layer of the second portion.

[0055] In some embodiments of the present invention, based on the total molar number of acetal groups, acetyl groups, and hydroxyl groups of the polyvinyl acetal contained in each layer of the second part, the hydroxyl group content of the polyvinyl acetal contained in each layer of the second part can be independently 20 mol% to 35 mol%, for example, 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 %, 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 a range consisting of any two of the foregoing values. In a preferred embodiment of the present invention, the hydroxyl content of the polyvinyl acetal contained in each layer of the second portion is independently 27 mol% to 29 mol%, based on the total molar number of acetal groups, acetyl groups, and hydroxyl groups of the polyvinyl acetal contained in each layer of the second portion.

[0056] 1.3.2. Plasticizers

[0057] Herein, plasticizer refers to a chemical substance that can change the plasticity of thermoplastic resin, and may also be referred to as plasticizer. Generally speaking, the higher the amount of plasticizer added, the higher the melt index of the polymer film. There is no particular limitation on the type of plasticizer, and the plasticizers contained in each layer of the first part and each layer of the second part may be the same or different. Examples of plasticizers include, but are not limited to, esters of polyacids or polyols, such as 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, cyclohexyl hexyl adipate, diisononyl adipate, heptylnonyl adipate, dibutyl sebacate, bis[2-(2-butoxyethoxy)ethyl adipate], polymeric 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) was used as a plasticizer.

[0058] In some embodiments of the present invention, in each layer of the first part, based on 100 parts by weight of the polyvinyl acetal contained in each layer, the content of the plasticizer contained in each layer may be independently 55 parts by weight to 85 parts by weight, for example, 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 consisting of any two of the above values. In a preferred embodiment of the present invention, in each layer of the first part, the content of the plasticizer contained in each layer is independently 60 parts by weight to 80 parts by weight, based on 100 parts by weight of the polyvinyl acetal contained in each layer.

[0059] In some embodiments of the present invention, in each layer of the second part, based on 100 parts by weight of the polyvinyl acetal contained in each layer, the content of the plasticizer contained in each layer can be independently 30 parts by weight to 50 parts by weight, for example, 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 consisting of any two of the foregoing values. In a preferred embodiment of the present invention, in each layer of the second part, based on 100 parts by weight of the polyvinyl acetal contained in each layer, the content of the plasticizer contained in each layer is independently 38 parts by weight to 44 parts by weight.

[0060] 1.3.3. Other existing additives

[0061] Existing additives may include any substance that can adaptably improve the processability of the polymer film during the manufacturing process or impart specific functionality to the polymer film. Such specific functionality includes, but is not limited to, one or more of the following: heat insulation, reflection, anti-reflection, refraction, anti-refraction, light splitting, and light reduction.

[0062] Examples of existing additives include, but are not limited to, dyes, pigments, stabilizers, antioxidants, flame retardants, infrared absorbers, infrared blockers, ultraviolet absorbers, ultraviolet stabilizers, lubricants, dispersants, surfactants, chelating agents, coupling agents, adhesives, and adhesion control agents. For example, a polymer film may include a dye or pigment to form a colored polymer film, or include an ultraviolet absorber or an infrared absorber to form a polymer film with UV protection or infrared protection. Each of the aforementioned additives may be used alone or in combination, and may be added to one or more layers of the first portion, one or more layers of the second portion, or one or more layers of both the first and second portions of the polymer film, as needed.

[0063] 1.4. Other properties of polymer films

[0064] In a preferred embodiment of the present invention, the thickness ratio of the first portion to the total thickness of the first portion and the second portion is 0.05 to 0.4, for example, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, or 0.4, or a range between any two of the foregoing values. The thickness ratio of the second portion to the total thickness of the first portion and the second portion is 0.6 to 0.95, for example, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, or 0.95, or a range between any two of the foregoing values.

[0065] Under the conditions of meeting the specified melt index and the sum of the products of the melt index and the thickness ratio, the total thickness of the polymer film of the present invention, the thickness of each layer of the first part, and the thickness of each layer of the second part can be adjusted according to actual needs. Generally speaking, the total thickness of the polymer film can be 0.1 mm to 2.5 mm, for example, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1.0 mm, 1.05 mm, 1.1 mm, 1.15 mm, 1.2 mm, 1.25 mm The thickness of the polymer film is preferably 1.5 mm, 1.6 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 consisting of any two of the foregoing values. In the following embodiments, the total thickness of the polymer film is between 0.76 mm and 0.85 mm.

[0066] In some embodiments of the present invention, the thickness of each layer of the first part may independently be 50 μm to 250 μm, for example, 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 within a range consisting of any two of the above values.

[0067] In some embodiments of the present invention, the thickness of each layer of the second part may independently be 250 μm to 450 μm, for example, 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 consisting of any two of the above values.

[0068] 1.5. Preparation of polymer membranes

[0069] The method for preparing the polymer film of the present invention is not particularly limited. For example, polyvinyl acetal can be mixed with selected ingredients (such as a plasticizer), dry-mixed, and kneaded to form a polymer film composition. The polymer film composition can then be formed into a film using existing film preparation methods, and the surface of the polymer film can be mechanically embossed. Examples of such film preparation methods include, but are not limited to, calendaring, casting, extrusion tentering, direct extrusion, and extrusion blow molding.

[0070] In some embodiments of the present invention, a polymer film is prepared as follows, but the present invention is not limited thereto: a first polymer film composition is provided to prepare each layer of the first part, and a second polymer film composition is provided to prepare each layer of the second part; and the first polymer film composition and the second polymer film composition are placed in a co-extruder to form the polymer film of the present invention by co-extrusion.

[0071] The first polymer film composition and the second polymer film composition can be independently prepared by the following method, but the present invention is not limited thereto: preheating the selected resin-state polyvinyl acetal in an oven; dry-mixing the preheated polyvinyl acetal with a plasticizer; and then mixing the dry-mixed mixture using a twin-screw mixer to obtain the desired first polymer film composition or second polymer film composition.

[0072] Without being limited by theory, the melt index can be adjusted by controlling the functional group content of the polymer, the plasticizer content of the polymer film, and the uniformity of plasticizer absorption into the polymer. The uniformity of plasticizer absorption into the polymer can be adjusted by controlling the preheating temperature, dry mixing temperature, dry mixing time, mixing temperature, and mixing time during the polymer film preparation process. Generally speaking, preheating can open the pores between the resins and allow the resin to develop some fluidity, facilitating subsequent mixing with the plasticizer. Higher dry mixing temperatures help open the pores between the resins, facilitating plasticizer absorption, while longer dry mixing times ensure more uniform mixing of the resin and plasticizer. Higher mixing temperatures can improve the fluidity of the plasticizer, thereby enhancing the compatibility of the plasticizer with the resin, while longer mixing times ensure more uniform mixing of the resin and plasticizer. Furthermore, the functional group content can also affect the uniformity of plasticizer absorption into the polymer. Based on the above, in the accompanying examples of the present invention, in addition to adjusting the composition ratio of the first polymer film composition and the second polymer film composition, the following conditions are also controlled to prepare a polymer film having the melt index characteristics of the present invention: preheating temperature of 30°C to 45°C; dry mixing temperature of 30°C to 45°C; dry mixing time of 2 minutes to 3 minutes; kneading temperature of 180°C to 210°C; and kneading time of 8 minutes to 12 minutes.

[0073] The polymer film of the present invention formed by co-extrusion can be further formed with a concave-convex structure on the surface by preheating and mechanical embossing to facilitate exhaust. Mechanical embossing refers to the use of a roller to create textures on the surface of the formed polymer film. The method of mechanical embossing includes but is not limited to the embossing wheel method and the calendering wheel method, among which the embossing wheel method is preferred. There is no special restriction on the pattern of mechanical embossing, for example, it includes diamond, linear, zigzag, square, conical, circular, approximately circular, and irregular shapes. The aforementioned pattern styles can be used alone or in combination. The preheating and mechanical embossing conditions can be adaptively adjusted according to the composition of the polymer film used.

[0074] 2. Laminated glass

[0075] The polymer film of the present invention can be used to prepare laminated glass. Therefore, the present invention also provides a laminated glass, which comprises a first glass sheet, an intermediate film and a second glass sheet in sequence, wherein the intermediate film is provided by the polymer film as described above.

[0076] The first and second glass sheets can be the same or different and can be any conventional glass sheet used to make laminated glass, such as float glass, tempered glass, wired glass, or ordinary flat glass, but the present invention is not limited thereto. In the following examples, float glass is used as the first and second glass sheets.

[0077] The laminated glass of the present invention can be produced by the existing laminated glass production method in the relevant technical field. Generally speaking, the production method of laminated glass can be roughly divided into a pre-pressing step and a positive pressing step. The pre-pressing step is as follows. First, a polymer film is sandwiched between two glass sheets to obtain a laminate. Then, the conveying speed of the conveyor belt of the roller press is set to 2m / min (meter / minute) to 8m / min, the temperature of the oven is set to 160℃ to 190℃, and the pressure of the roller is set to 3kg / cm 2 (kg / cm2) to 10kg / cm 2 , place the laminate on a conveyor belt and pass it through an oven and rollers in sequence, where the distance between the rollers is set to 4.5 mm to 6.5 mm. Afterwards, the rolled laminate is cooled to room temperature to complete the pre-pressing. The pre-pressed laminate is then placed in an autoclave for a positive pressing step. The positive pressing step includes hot pressing the pre-pressed laminate under high temperature and high pressure conditions for 100 minutes to 150 minutes to produce laminated glass. Generally speaking, the high temperature and high pressure conditions can be a pressure of 10 bar to 15 bar and a temperature of 100°C to 150°C.

[0078] 3. Examples

[0079] 3.1. Measurement method description

[0080] The present invention is further illustrated by the following specific examples, wherein the measuring instruments and methods used are as follows:

[0081] Measurement of acetal degree, acetylation degree and hydroxyl content of polyvinyl acetal

[0082] The acetalization degree, acetylation degree and hydroxyl content of polyvinyl acetal are measured according to JIS K6728:1977.

[0083] "Measurement of Molecular Weight of Polyvinyl Acetal" The molecular weight distribution of polyvinyl acetal was measured using gel permeation chromatography (GPC). Polyvinyl acetal was dissolved in tetrahydrofuran (THF) and GPC analysis was performed under the following conditions. The molecular weight (Mn) was calculated as the ratio of the area to the corresponding polystyrene standard (Waters PS STD).

[0084] Device: Waters 1515PUMP system;

[0085] Detector: Waters 2414RI;

[0086] Elution conditions: 1.0 mL / min, THF;

[0087] Column: Waters Styragel HR5 THF, Waters Styragel HR4 THF, Waters;

[0088] Styragel HR3 THF, Waters Styragel HR1 THF.

[0089] 《Measuring Melt Index》

[0090] According to ASTM D1238, the melt index of the polymer film is measured using a melt index tester (model: D4002HV, purchased from Dynisco), and the weight of the effluent is calculated according to the manual operation method (Method A). The test conditions are 190°C and 2.16 kg load, and the sample weight is 6 grams. The detailed measurement steps are as follows. First, the 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 turned on and heated to 190°C, and then the sample is placed in the barrel and pressed tightly. After placing the piston rod and weight (the total weight of the two is 2.16 kg), the time is set for 120 seconds, and the effluent during this period is not counted. The formal test begins after 120 seconds, and the effluent is taken every 200 seconds for weight measurement, for a total of 3 times, and the melt index is calculated according to the following formula. The unit of the melt index is grams / 10 minutes.

[0091]

[0092] Evaluation of Continuous Layer Structures

[0093] An optical microscope (model: BX51, purchased from Olympus) was used to observe whether the structure of each layer of the polymer film was continuous. The polymer film was cut into samples of 100 cm x 5 cm, where 100 cm was the length in the perpendicular machine direction and 5 cm was the length in the machine direction. The two short sides of the sample were clamped using a clamping fixture so that the long side of the film (i.e., the cut surface) was facing the objective lens. The configuration of the optical microscope was as follows: the objective lens magnification was set to 5x. The evaluation criteria were as follows: when the structure of each layer in the polymer film was continuous and uninterrupted, it indicated good structural uniformity and was recorded as "○"; when the structure of any layer in the polymer film was interrupted, it indicated good structural uniformity and was recorded as "×".

[0094] Layer Thickness Analysis

[0095] An optical microscope (model: BX51, purchased from Olympus) was used to measure the thickness of each layer of the first part and each layer of the second part, and the built-in software of the optical microscope (Motic Image Plus 2.0) was used to calculate the thickness. The polymer film was cut into samples of 100 cm × 5 cm, of which 100 cm was the length in the perpendicular machine direction and 5 cm was the length in the machine direction. The two short sides of the sample were clamped using a clamping fixture so that the long side of the film (i.e., the cut surface) faced the objective lens. The configuration of the optical microscope was as follows: the objective lens magnification was set to 5 times. The measurement method was as follows: starting from the left boundary, the thickness of each layer of the first part and each layer of the second part was measured at 1 cm, 25 cm, 50 cm, 75 cm and 100 cm, for a total of five values. The five values were averaged to obtain the thickness of each layer of the first part and each layer of the second part.

[0096] Loss Coefficient Evaluation

[0097] The loss coefficient of laminated glass was evaluated using the mechanical impedance measurement (MIM) method according to ISO 16940:2008. Sample preparation was as follows: a polymer film 300 mm long and 25 mm wide was sandwiched between two sheets of clear float glass (300 mm long, 25 mm wide, and 2 mm thick) to form a laminate. The laminate was then subjected to a pre-lamination and a positive lamination step to produce the laminated glass, where the pre-lamination and positive lamination steps were as described above. The laminated glass was then placed in a constant temperature and humidity chamber at 23°C and 55% relative humidity for 2 hours. The loss coefficient was then measured as follows: First, the center of the laminated glass was fixed to a vibration shaker and shaken at an ambient temperature of 20°C. Next, an impedance head was used to measure the force and frequency of the oscillations of the laminated glass. An analysis system then converted these values into a damping loss factor, calculated using the half-power method for the first vibration mode. A damping loss factor greater than 0.25 at 20°C indicates good sound insulation.

[0098] Ball Drop Test

[0099] The penetration resistance test is conducted at 23°C according to the JIS R 3212:1998 standard (hereinafter referred to as the "3212 standard"). First, five 30 cm x 30 cm laminated glass sheets are prepared as test samples. Next, the test samples are placed on a steel support frame according to the 3212 standard. A steel ball weighing 2260 grams and 82 mm in diameter is placed 5 meters above the test sample and allowed to fall freely onto the test sample. The test is checked to see if the steel ball penetrates the sample. A total of five tests are performed. If the steel ball does not penetrate the sample in all five tests, the test passes and is recorded as "○". If the steel ball penetrates the sample in any one of the five tests, the test fails and is recorded as "×".

[0100] Snowflake Defect Test

[0101] Herein, a snowflake defect refers to a defect resembling a snowflake that appears between the first and second portions of a polymer film. Generally, these defects are easily formed during the manufacturing process of laminated glass, adversely affecting the optical performance of the laminated glass. The snowflake defect test method is as follows.

[0102] Prepare a 15 cm x 15 cm laminated glass sample as a test sample. Place the test sample in a 120°C oven for 2 hours. After removing the test sample, visually inspect the glass for any snowflake defects. If there are no snowflake defects, the test is passed and recorded as "○". If there are snowflake defects, the test is failed and recorded as "X".

[0103] Light transmittance measurement

[0104] The light transmittance of laminated glass was measured according to ASTM D1003. First, two flat glass sheets (6 cm long, 6 cm wide, and 3 mm thick) were washed with water and dried. Then, a polymer film was placed between the two glass sheets and heated in a hot press at 150°C and 3 kg / cm 2 After hot pressing for 3 minutes under pressure, the laminated glass was cleaned with alcohol. The light transmittance of the laminated glass was then measured using a haze meter (model: NDH2000 Haze Meter, purchased from Nippon Denshoku). Generally speaking, a satisfactory light transmittance for laminated glass is 87.5% or higher.

[0105] 3.2. Preparation and property measurement of polymer films

[0106] 3.2.1. First part of the polymer film

[0107] 100 parts by weight of polyvinyl butyral (PVB, purchased from Changchun Petrochemical Co., Ltd.) was preheated in an oven at 30°C to 45°C for 1 minute; then, the preheated PVB was dry-mixed with a plasticizer at a first dry-mixing temperature for a first dry-mixing time to obtain a first dry-mixed mixture; thereafter, the first dry-mixed mixture was kneaded using a twin-screw mixer at the first kneading temperature for a first kneading time to obtain the first polymer film compositions of Examples 1 to 11 and Comparative Examples 1 to 11, respectively. The amount of plasticizer used is shown in Tables 1-1 and 2-1, and the first dry-mixing temperature, first dry-mixing time, first kneading temperature, and first kneading time are shown in Tables 1-2 and 2-2. The Mn, acetalization degree, acetylation degree, and hydroxyl content ratio of the PVB used were measured according to the methods described above, and the results are recorded in Tables 1-1 and 2-1. The units of acetalization degree, acetylation degree, and hydroxyl content ratio are all mole %.

[0108] The first polymer film compositions of Examples 1-11 and Comparative Examples 1-11 were extruded into single-layer polymer films (hereinafter referred to as "first single-layer polymer films") in an extruder. The melt index of each of the first single-layer polymer films was measured according to the method described above. The results are reported in Tables 1-6 and 2-6, referred to as "Layer 1 Melt Index" in the tables. Each of these first polymer film compositions is used as the material for each layer of the first portion of the polymer films of Examples 1-11 and Comparative Examples 1-11. Therefore, the melt index of each first single-layer polymer film represents the melt index of each layer of the first portion.

[0109] 3.2.2. Second part of the polymer film

[0110] 100 parts by weight of PVB were preheated in an oven at 30°C to 45°C for 1 minute; then, the preheated PVB was dry-mixed with a plasticizer at a second dry-mixing temperature for a second dry-mixing time to obtain a second dry-mixed mixture; thereafter, the second dry-mixed mixture was kneaded using a twin-screw mixer at a second kneading temperature for a second kneading time to obtain the second polymer film compositions of Examples 1 to 11 and Comparative Examples 1 to 11, respectively. The amount of plasticizer used is shown in Tables 1-3 and 2-3, and the second dry-mixing temperature, second dry-mixing time, second kneading temperature, and second kneading time are shown in Tables 1-4 and 2-4. The Mn, acetalization degree, acetylation degree, and hydroxyl content ratio of the PVB used were measured according to the methods described above, and the results are recorded in Tables 1-3 and 2-3. The units of acetalization degree, acetylation degree, and hydroxyl content ratio are all molar%.

[0111] The second polymer film compositions of Examples 1-11 and Comparative Examples 1-11 were extruded into single-layer polymer films (hereinafter referred to as "second single-layer polymer films") in an extruder. The melt index of each of the second single-layer polymer films was measured according to the method described above. The results are reported in Tables 1-7 and 2-7, as "Layer II Melt Index." Each of these second polymer film compositions serves as the material for each layer of the second portion of the polymer films of Examples 1-11 and Comparative Examples 1-11, respectively. Therefore, the melt index of each second single-layer polymer film represents the melt index of each layer of the second portion.

[0112] Preparation of polymer membranes

[0113] The first polymer film compositions and the second polymer film compositions of Examples 1-11 and Comparative Examples 1-11 were each placed in a coextruder to form polymer films by coextrusion. The polymer films had a total thickness of 0.8 mm, and the compositions of the polymer films are shown in Tables 1-5 and 2-5, where "Layer I" represents the first layer of the polymer film formed from the first polymer film composition, and "Layer II" represents the second layer of the polymer film formed from the second polymer film composition. The total thickness of Layer I, constituting the first portion of the polymer film, and its ratio to the total thickness of the first and second portions are reported in Tables 1-6 and 2-6, and the total thickness of Layer II, constituting the second portion of the polymer film, and its ratio to the total thickness of the first and second portions are reported in Tables 1-7 and 2-7. In embodiments where layer I or layer II comprises two or more layers, each layer I has the same thickness, and each layer II has the same thickness. Therefore, the thickness ratio of each individual layer can be calculated from the total thickness ratio listed in the table. This can be used to calculate the product of the melt index of each layer and the thickness ratio of its share of the total thickness of the first portion and the second portion, as well as the sum of these products for each layer of the corresponding first portion or second portion.

[0114] Afterwards, both surfaces of each polymer film were preheated and mechanically embossed to form surface textures, thereby obtaining the polymer films of Examples 1 to 11 and Comparative Examples 1 to 11.

[0115] Table 1-1: Properties of the first polymer film compositions of Examples 1 to 11

[0116]

[0117]

[0118] Table 1-2: Preparation parameters of the first polymer film composition of Examples 1 to 11

[0119]

[0120] Table 1-3: Properties of the Second Polymer Film Compositions of Examples 1 to 11

[0121]

[0122] Table 1-4: Preparation parameters of the second polymer film composition of Examples 1 to 11

[0123]

[0124] Table 1-5: Composition of polymer films of Examples 1 to 11

[0125]

[0126] Table 1-6: Properties of polymer films of Examples 1 to 11

[0127]

[0128] Table 1-7: Properties of polymer films of Examples 1 to 11

[0129]

[0130] Table 2-1: Properties of the first polymer film compositions of Comparative Examples 1 to 11

[0131]

[0132]

[0133] Table 2-2: Preparation parameters of the first polymer film composition of Comparative Examples 1 to 11

[0134]

[0135] Table 2-3: Properties of the Second Polymer Film Compositions of Comparative Examples 1 to 11

[0136]

[0137]

[0138] Table 2-4: Preparation parameters of the second polymer film compositions of Comparative Examples 1 to 11

[0139]

[0140] Table 2-5: Composition of polymer films of Comparative Examples 1 to 11

[0141]

[0142] Table 2-6: Properties of polymer films of Comparative Examples 1 to 11

[0143]

[0144] Table 2-7: Properties of polymer films of Comparative Examples 1 to 11

[0145]

[0146] 3.3. Preparation and property evaluation of laminated glass

[0147] The polymer films of Examples 1 to 11 and Comparative Examples 1 to 11 were used to prepare laminated glass. First, the polymer film was cut into a size of 300 mm x 300 mm. Next, two clean transparent float glass sheets (length 300 mm, width 300 mm, thickness 2 mm) were prepared, and the cut polymer film was sandwiched between the two transparent float glass sheets to obtain a laminate. The laminate was vacuumed using a pressure wheel method for pre-pressing. The operation of the pressure wheel method is as follows: the conveying rate of the conveyor belt of the roller press is set to 4.5 m / min, the temperature of the oven is set to 180°C, and the pressure of the roller is set to 3 kg / cm 2 The laminate is placed on a conveyor belt and passed through an oven, then between rollers, with the rollers set at a distance of 5 mm. The pre-laminated laminate is then placed in an autoclave at a pressure of 13 bar and a temperature of 135°C for 120 minutes, followed by cooling to room temperature to produce laminated glass.

[0148] The polymer films of Examples 1 to 11 and Comparative Examples 1 to 11 and laminated glass were subjected to continuous layer structure evaluation, loss coefficient evaluation, drop ball test, snowflake defect test, and light transmittance measurement according to the methods described above. The results are recorded in Tables 3-1 and 3-2.

[0149] Table 3-1: Properties of polymer films and laminated glasses of Examples 1 to 11

[0150]

[0151] Table 3-2: Properties of polymer films and laminated glasses of Comparative Examples 1 to 11

[0152]

[0153]

[0154] As shown in Table 3-1, Examples 1 to 11 demonstrate that the polymer films of the present invention possess a continuous layer structure with excellent structural uniformity. Laminated glass produced from these polymer films all exhibited a loss coefficient exceeding 0.25, indicating excellent sound insulation. Furthermore, these laminated glasses all passed the drop ball test and the snowflake defect test, and exhibited acceptable light transmittance.

[0155] In contrast, as shown in Table 3-2, laminated glass produced using polymer films other than those of the present invention fails to achieve the combined benefits of excellent sound insulation, optical properties, and safety. In particular, Comparative Examples 1 and 11 demonstrate that even if the melt index and the sum of the products of the melt index and thickness ratio of each layer in the second portion are within the specified ranges, if the melt index and the sum of the products of the melt index and thickness ratio of each layer in the first portion are below the specified ranges, the polymer film structure exhibits poor uniformity and the resulting laminated glass exhibits poor sound insulation (loss coefficient below 0.25). Comparative Example 2 demonstrates that even if the melt index and the sum of the products of the melt index and thickness ratio of each layer in the second portion are within the specified ranges, if the melt index and the sum of the products of the melt index and thickness ratio of each layer in the first portion are above the specified ranges, the resulting laminated glass fails to achieve excellent safety (fails the drop ball test) and exhibits poor optical properties (fails the snowflake defect test and has a light transmittance below 87.5%). Comparative Examples 3 and 4 show that even if the melt index and the sum of the products of the melt index and thickness ratio of each layer in the second part are within the specified range, and the melt index of each layer in the first part is also within the specified range, if the sum of the products of the melt index and thickness ratio of each layer in the first part falls outside the specified range, the resulting laminated glass will have poor sound insulation (loss coefficient less than 0.25) or poor optical properties (light transmittance less than 87.5%). Comparative Example 5 shows that even if the melt index and the sum of the products of the melt index and thickness ratio of each layer in the first part are within the specified range, if the melt index and the sum of the products of the melt index and thickness ratio of each layer in the second part are above the specified range, the resulting laminated glass will not provide excellent safety (fails the drop ball test) and has poor optical properties (fails the snowflake defect test and has light transmittance less than 87.5%). Comparative Example 6 shows that even if the melt index and the sum of the products of the melt index and thickness ratio of each layer in the first part are within the specified range, as long as the melt index and the sum of the products of the melt index and thickness ratio of each layer in the second part are below the specified range, the optical properties of the resulting laminated glass are poor (failing the snowflake defect test). Comparative Example 7 shows that when the melt index and the sum of the products of the melt index and thickness ratio of each layer in the first and second parts are both above the specified range, the resulting laminated glass cannot provide excellent safety (failing the drop ball test) and has poor optical properties (failing the snowflake defect test and having a light transmittance of less than 87.5%). Comparative Example 8 shows that when the melt index and the sum of the products of the melt index and thickness ratio of each layer in the first and second parts are both below the specified range, the polymer film structure is poorly uniform and the resulting laminated glass has poor sound insulation (the loss coefficient is less than 0.25).Comparative Example 9 shows that when the sum of the products of the melt index and thickness ratio of each layer in the first part and the sum of the products of the melt index and melt index and thickness ratio of each layer in the second part both fall outside the specified ranges, the resulting laminated glass fails to exhibit excellent safety (fails to pass the drop ball test) and has poor optical properties (fails to pass the snowflake defect test and has a light transmittance of less than 87.5%). Comparative Example 10 shows that when the sum of the products of the melt index and melt index and thickness ratio of each layer in the first part exceeds the specified range and the sum of the products of the melt index and melt index and thickness ratio of each layer in the second part falls below the specified range, the resulting laminated glass also fails to exhibit excellent safety (fails to pass the drop ball test) and has poor optical properties (fails to pass the snowflake defect test and has a light transmittance of less than 87.5%).

[0156] The above embodiments are intended only to illustrate the principles and efficacy of the present invention and to illustrate the technical features of the present invention, and are not intended to limit the scope of protection of the present invention. Any modifications or arrangements that can be readily accomplished by a person skilled in the art without violating the technical principles of the present invention are within the scope of the present invention.

Claims

1. A polymer film, characterized in that The invention comprises a first part and a second part laminated with the first part, wherein the first part and the second part are each independently composed of one or more layers, wherein: Each layer of the first part independently has a melt index of 3.5 g / 10 minutes to 10.0 g / 10 minutes, and each layer of the second part independently has a melt index of less than 3.5 g / 10 minutes; each layer of the first part independently has a product of its melt index and its thickness ratio to the total thickness of the first part and the second part, provided that the sum of the products of the layers of the first part is from 0.39 g / 10 minutes to 2.50 g / 10 minutes; and Each layer of the second part independently has a product of its melt index and its thickness ratio to the total thickness of the first part and the second part, provided that the sum of the products of the layers of the second part is 1.10 g / 10 minutes to 2.95 g / 10 minutes, Each layer of the first part and each layer of the second part independently contain polyvinyl acetal, The melt index is measured according to ASTM D1238 at 190° C. and a load of 2.16 kg.

2. A polymer film according to claim 1, characterized in that The melt index of each layer of the second part is independently 1.5 g / 10 min to 3.3 g / 10 min.

3. A polymer film according to claim 1, characterized in that Each layer of the first part and each layer of the second part independently contain polyvinyl butyral.

4. A polymer film according to claim 2, characterized in that Each layer of the first part and each layer of the second part independently contain polyvinyl butyral.

5. The polymer film according to claim 1, characterized in that Each layer of the first part independently contains polyvinyl acetal having the following properties: an acetal degree of 56 mol % to 74 mol %, an acetylation degree of 5 mol % to 15 mol %, and a hydroxyl content of 20 mol % to 30 mol %.

6. A polymer film according to claim 1, characterized in that Each layer of the second part independently contains polyvinyl acetal having the following properties: an acetal degree of 60 mol % to 75 mol %, an acetylation degree of 0.1 mol % to 5 mol %, and a hydroxyl content of 20 mol % to 35 mol %.

7. The polymer film according to claim 1, characterized in that The number average molecular weight of the polyvinyl acetal contained in each layer of the first part is independently 100,000 to 240,000.

8. The polymer film according to claim 1, characterized in that The number average molecular weight of the polyvinyl acetal contained in each layer of the second part is independently 90,000 to 120,000.

9. The polymer film according to claim 1, characterized in that Each layer of the first part and each layer of the second part independently further contain a plasticizer.

10. The polymer film according to claim 2, characterized in that Each layer of the first part and each layer of the second part independently further contain a plasticizer.

11. The polymer film according to claim 9, characterized in that In each layer of the first part, the content of the plasticizer contained in each layer is independently 55 parts by weight to 85 parts by weight based on 100 parts by weight of the polyvinyl acetal contained in each layer; and in each layer of the second part, the content of the plasticizer contained in each layer is independently 30 parts by weight to 50 parts by weight based on 100 parts by weight of the polyvinyl acetal contained in each layer.

12. A polymer film according to claim 10, characterized in that In each layer of the first part, the content of the plasticizer contained in each layer is independently 55 parts by weight to 85 parts by weight based on 100 parts by weight of the polyvinyl acetal contained in each layer; and in each layer of the second part, the content of the plasticizer contained in each layer is independently 30 parts by weight to 50 parts by weight based on 100 parts by weight of the polyvinyl acetal contained in each layer.

13. The polymer film according to claim 1, characterized in that Each layer of the first part constitutes M first sub-parts, each layer of the second part constitutes N second sub-parts, and the second sub-parts and the first sub-parts are arranged alternately, wherein M and N are each independently a positive integer.

14. A polymer film according to claim 2, characterized in that Each layer of the first part constitutes M first sub-parts, each layer of the second part constitutes N second sub-parts, and the second sub-parts and the first sub-parts are arranged alternately, wherein M and N are each independently a positive integer.

15. A polymer film according to claim 13, characterized in that Where N is M+1.

16. A polymer film according to claim 14, characterized in that Where N is M+1.

17. A laminated glass, characterized in that: The invention comprises a first glass sheet, an intermediate film and a second glass sheet in sequence, wherein the intermediate film is the polymer film according to claim 1 .

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