CN116254063A - Polymer film - Google Patents

Abstract

The present invention relates to a polymer film comprising a polyvinyl acetal resin and a plasticizer; wherein the polymer film comprises at least a first layer and a second layer, the loss factors of the first layer and the second layer are different; and the ratio of the loss factor of the first layer to the second layer is 1.30 to 3.12. The polymer film provided by the invention has an improved sound insulation effect.

Description

Polymer film

Technical Field

The present invention mainly relates to a polymer film; in particular, the present invention relates to a polymer film suitable for an intermediate film of laminated glass.

Background Art

Laminated glass is a type of safety glass that is held together when broken. Laminated glass consists of a membrane, usually made of polyvinyl butyral (PVB) or ethylene vinyl acetate (EVA), contained between two or more layers of glass. The membrane keeps the layers of glass together even if they break, and its high strength prevents the glass from breaking into large, sharp fragments. When the impact force is not strong enough to completely penetrate the glass, a characteristic "spider web" crack morphology is created.

In addition to the above safety features, laminated glass is also suitable for sound insulation. Compared with single-layer glass windows of the same thickness, laminated glass has a better sound wave attenuation effect. For this purpose, the diaphragm in the laminated glass can use a multi-layer structure of PVB diaphragm to improve the sound insulation effect of the diaphragm.

Specifically, the glass transition temperature (Tg) of the above-mentioned diaphragm is considered to directly determine the sound insulation effect of the diaphragm; the so-called glass transition temperature refers to the temperature at which a substance can reversibly transform between a glassy state (a state in which the material is in a state of low fluidity) and a highly elastic state (a state in which the material is in a state of high fluidity and softness). Generally, the lower the glass transition temperature of the diaphragm, the more likely the technicians in this field will judge that the diaphragm is in a state of high fluidity and softness, and thus has a better sound insulation effect.

Summary of the invention

The invention summary is intended to provide a simplified summary of the invention so that readers can have a basic understanding of the invention. This invention summary is not a complete overview of the invention and is not intended to identify important or critical components of the embodiments of the invention or to define the scope of the invention.

The inventors have found that the prior art reliance on glass transition temperature as the main criterion for determining the sound insulation effect of a diaphragm is questionable. The lower the glass transition temperature of a diaphragm, the better the sound insulation effect.

The inventors believe that when the diaphragm is arranged in a multi-layer structure, the material difference between different layers can effectively reduce the vibration of the sound during the penetration process, thereby achieving the effect of sound insulation; in particular, the difference in damping characteristics between different layers is related to its sound insulation effect and the uniformity of the overall structure. Specifically, the viscoelasticity of the above-mentioned diaphragm is regarded as an important parameter that determines the sound insulation effect. The so-called viscoelasticity refers to the combination of viscosity and elasticity, that is, the combination of the flow characteristics of viscous fluid and elastic fluid; through the difference in viscoelasticity in the multi-layer structure, the sound is disturbed by the medium during the penetration process, and the sound waves are converted into storage energy and consumption energy of the material molecular motion, thereby achieving the effect of reducing the volume. When there is an appropriate difference in the loss factor (tanδ) between the middle layer and the protective layer of the multi-layer membrane, the sound can be more effectively used by the material during the penetration process, thereby achieving an improved sound insulation effect.

In addition, the diaphragm usually contains plasticizers; and the inventors have found that the quality of the plasticizer compatibility of the diaphragm may be related to the sound insulation effect and film-forming properties of the diaphragm. For example, when the resin cannot absorb more plasticizers, the viscoelastic differences between the multilayer films cannot be effectively distinguished, so that the sound cannot be effectively absorbed by the material during the penetration process, thereby weakening the sound insulation effect; and the inability of the resin to absorb more plasticizers will cause the plasticizer to seep out, resulting in poor film-forming properties of the diaphragm. Furthermore, the inventors believe that the difference in loss factor between the intermediate layer and the protective layer is too large, that is, the ratio of the loss factors of the two is too large or too small; or when the hydroxyl content of the diaphragm is too low, it may cause the plasticizer compatibility of the diaphragm to decrease.

Accordingly, one aspect of the present invention provides a polymer film, which comprises a polyvinyl acetal resin and a plasticizer; and the polymer film comprises at least a first layer and a second layer, the loss factor (tanδ) of the first layer is different from that of the second layer, and the ratio of the loss factor of the first layer to that of the second layer is 1.30 to 3.12.

According to an embodiment of the present invention, based on 100 parts by weight of the polyvinyl acetal resin in the first layer, the plasticizer accounts for 50 to 90 parts by weight.

According to an embodiment of the present invention, the polyvinyl acetal resin of the first layer has a hydroxyl content ratio greater than 16.0 mol % and less than 30.6 mol %.

According to an embodiment of the present invention, the degree of polymerization of the polyvinyl acetal resin of the first layer is greater than 1750 and less than 3850.

According to an embodiment of the present invention, the polyvinyl acetal resin of the first layer has an acetylation degree less than 20 mol %.

According to an embodiment of the present invention, the glass transition temperature (Tg) of the first layer is -7 to 6°C.

According to an embodiment of the present invention, the loss factor of the first layer is 0.70 to 1.38.

According to an embodiment of the present invention, based on 100 parts by weight of the polyvinyl acetal resin in the second layer, the plasticizer accounts for 30 to 60 parts by weight.

According to an embodiment of the present invention, the polyvinyl acetal resin of the second layer has a hydroxyl content ranging from 25 mol % to 31 mol %.

According to one embodiment of the present invention, the glass transition temperature (Tg) of the second layer is 25 to 35°C.

According to an embodiment of the present invention, the loss factor of the second layer is 0.37 to 0.94.

According to an embodiment of the present invention, the polymer film is a three-layer structure, and in the three-layer structure, the upper and lower layers are the second layers, and the first layer is sandwiched in the middle.

According to an embodiment of the present invention, the damping loss coefficient of the polymer film at 20° C. obtained according to the MIM mechanical impedance method (Measurement of Mechanical Impedance) of ISO 16940 is greater than 0.25.

According to an embodiment of the present invention, the polymer film is an intermediate film for laminated glass, and has a thickness of 0.5 to 2 mm.

According to an embodiment of the present invention, the polymer film has a thickness of 0.8 mm, and the second layer/first layer/second layer has a thickness of 0.335 mm/0.13 mm/0.335 mm.

According to an embodiment of the present invention, the polyvinyl acetal is polyvinyl butyral (PVB).

The advantages of the polymer film provided by the present invention are that the polymer film can obtain good sound insulation effect based on the definition of the above characteristics; and according to some preferred embodiments, it can also have ideal structure and film-forming properties at the same time.

BRIEF DESCRIPTION OF THE DRAWINGS

To make the above and other objects, features, advantages and embodiments of the present invention more understandable, the attached drawings are described as follows:

1 to 3 are cross-sectional views of polymer film stacks according to different embodiments of the present invention;

FIG. 4 is a flow chart of manufacturing a polymer film according to an embodiment of the present invention.

Reference numerals:

Polymer films 100A to 100C, a first layer 101 , a second layer 102 , and steps S100 to S106 .

According to conventional working methods, various features and components in the drawings are not drawn according to actual scale, and the drawing method is to present specific features and components related to the present invention in the best way. In addition, similar components and parts are referred to by the same or similar component symbols in different drawings.

DETAILED DESCRIPTION

In order to make the description of the present invention more detailed and complete, the following is an illustrative description of the implementation mode and specific examples of the present invention, but this is not the only form of implementing or using the specific examples of the present invention. In this specification and the attached claims, unless the context otherwise states, "a" and "the" may also be interpreted as plural. In addition, in this specification and the attached claims, unless otherwise stated, "disposed on something" may be regarded as directly or indirectly contacting the surface of something by attachment or other forms, and the definition of the surface should be judged according to the context/paragraph meaning of the content of the specification and the common knowledge in the field to which the specification belongs.

Although the numerical ranges and parameters used to define the present invention are approximate values, the relevant numerical values in the specific embodiments have been presented as accurately as possible. However, any numerical value inherently inevitably contains standard deviations due to individual test methods. Here, "about" usually means that the actual value is within plus or minus 10%, 5%, 1% or 0.5% of a specific value or a range. Alternatively, the word "about" represents that the actual value falls within the acceptable standard error of the mean value, which is determined by the technicians in this field. Therefore, unless otherwise stated to the contrary, the numerical parameters disclosed in this specification and the attached claims are all approximate values and can be changed as needed. At least these numerical parameters should be understood as the indicated significant digits and the values obtained by applying the general rounding method.

The present invention provides a polymer film, which includes a polyvinyl acetal resin and a plasticizer. Specifically, the polyvinyl acetal resin described herein refers to a resin composition formed by condensation of polyvinyl alcohol and aldehyde; wherein the polyvinyl alcohol can be obtained by saponifying polyvinyl ester, and the saponification degree of the polyvinyl alcohol is generally in the range of 70 mol% to 99.9 mol%, for example: 70 mol%, 75 mol%, 80 mol%, 85 mol%, 90 mol%, 95 mol%, 99 mol% or 99.9 mol%. The aldehyde can generally be an aldehyde with a carbon number of 1 to 10, for example: formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, 2-ethylbutyraldehyde, n-hexanal, n-octanal, n-nonanal, n-decanal and benzaldehyde; preferably, the aldehyde is propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-hexanal or n-valeraldehyde; more preferably, propionaldehyde, n-butyraldehyde or isobutyraldehyde. According to one embodiment of the present invention, the polyvinyl acetal is polyvinyl butyral (PVB).

On the other hand, the plasticizer is also called a plasticizer, which is usually used in combination with the polyvinyl acetal resin to affect the viscoelastic properties of the material. Specifically, the plasticizer is selected from the group consisting of monobasic acid esters, polybasic acid esters, organic phosphoric acids and organic phosphorous acids without limitation; the plasticizer is more specifically selected from the group consisting of triethylene glycol bis(2-ethylhexanoate) (3GO), 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, di[2-(2- The invention also comprises a group consisting of propylene glycol dibenzoate, dipropylene glycol dibenzoate, tripropylene glycol dibenzoate, polypropylene glycol dibenzoate, 2,2,4-trimethyl-1,3-pentanediol dibenzoate, isodecyl benzoate, 2-ethylhexyl benzoate, diisononyl phthalate, dibutoxyethyl terephthalate, castor oil, methyl ricinoleate, soybean oil, and epoxidized soybean oil.

Next, the polymer film comprises at least a first layer and a second layer, and the loss factors of the first layer and the second layer are different. The loss factor described in this article is tanδ (also known as loss factor, damping factor, loss tangent), which is used to express the damping characteristics in the viscoelastic properties of the material, and can be equivalent to the ratio of the loss modulus (or loss modulus, viscosity modulus, loss modulus, G”) to the storage modulus (or elastic modulus, storage modulus, G’) of the material; further, the peak value of the loss factor corresponding to the temperature is the glass transition temperature (glass transition temperature, Tg). Generally, the loss factor is positively correlated with the viscosity of the material; and the lower the glass transition temperature, the softer the material can be roughly inferred.

According to at least one preferred embodiment, the ratio of the loss factors of the first layer and the second layer of the above-mentioned polymer film is 1.30 to 3.12; for example: 1.30, 1.32, 1.46, 1.49, 1.62, 1.75, 1.78, 1.83, 1.87, 1.92, 1.97, 2.31, 2.41, 3.00 or 3.12. In the polymer film provided by the present invention, the loss factor of the first layer is 0.70 to 1.38, for example, 0.70, 0.89, 0.94, 0.96, 0.99, 1.17, 1.18, 1.20, 1.21, 1.24, 1.26, 1.28, 1.31 or 1.38; on the other hand, the loss factor of the second layer is 0.37 to 0.94, for example, 0.37, 0.42, 0.46, 0.52, 0.54, 0.61, 0.63, 0.65, 0.67, 0.78 or 0.94.

In addition, according to some embodiments of the present invention, the glass transition temperature of the first layer is -7 to 6°C; preferably, its glass transition temperature is -6.99 to 5.26°C; and according to other embodiments of the present invention, the glass transition temperature of the second layer is 25 to 35°C; preferably, the glass transition temperature of the second layer is 26.63 to 33.19°C.

In the polymer film provided by the present invention, the polyvinyl acetal resin contained in the first layer is calculated based on 100 parts by weight, and the plasticizer is 50 to 90 parts by weight. Specifically, the polyvinyl acetal resin is calculated based on 100 parts by weight, and the plasticizer is 60 to 90 parts by weight; preferably, the plasticizer is 60 to 70 parts by weight, for example: 60, 61, 62, 63, 64, 65, 66, 67, 68, 69 or 70 parts by weight. According to some embodiments of the present invention, the polyvinyl acetal resin contained in the second layer is calculated based on 100 parts by weight, and the plasticizer is 30 to 60 parts by weight; preferably, the plasticizer is 37 to 43 parts by weight, for example: 37, 38, 39, 40, 41, 42 or 43 parts by weight.

Without being limited by any particular theory, the hydroxyl content ratio of the polyvinyl acetal resin is considered to be related to the plasticizer compatibility. The hydroxyl content ratio of the polyvinyl acetal resin described herein refers to the molar fraction obtained by dividing the amount of ethylene bonded to the hydroxyl group by the total amount of ethylene in the main chain, expressed as a percentage. In the polymer film provided by the present invention, the hydroxyl content ratio of the polyvinyl acetal resin contained in the first layer is greater than 15.0 mol% and less than 30.6 mol%; preferably, its hydroxyl content ratio is greater than 16.0 mol% and less than 30.6 mol%; more preferably, its hydroxyl content ratio is between 16.4 and 30.0 mol%, for example: 16.4, 19.2, 22.6, 23.3, 23.8, 24.7, 25.0, 25.1, 25.7, 29.3 or 30.0 mol%. According to some embodiments of the present invention, the hydroxyl content of the polyvinyl alcohol acetal resin contained in the second layer is between 25 mol% and 31 mol%; preferably, the hydroxyl content is between 27.4 and 30.8 mol%, for example: 27.4, 27.5, 27.6, 27.7, 27.9, 28.1, 28.3, 28.4, 29.6 or 30.8 mol%.

The acetalization degree (or acetalization degree) of the polyvinyl acetal resin described herein refers to the molar fraction obtained by dividing the amount of ethylene groups bonded to the acetal group by the total amount of ethylene groups in the main chain, expressed as a percentage.

The degree of acetylation of the polyvinyl acetal resin described herein is a value expressed as a percentage, which is the molar fraction obtained by subtracting the amount of ethylene groups bonded to hydroxyl groups and the amount of ethylene groups bonded to acetal groups from the total amount of ethylene groups in the main chain, and then dividing the obtained value by the total amount of ethylene groups in the main chain. In the polymer film provided by the present invention, the degree of acetylation of the polyvinyl acetal resin in the first layer is less than 20 mol %; preferably, the degree of acetylation is 8.0 to 11.8 mol %, for example: 8.0, 8.2, 8.5, 9.2, 9.6, 10.1, 10.2, 10.5, 11.5, 11.8 mol %.

The above-mentioned hydroxyl content ratio, acetalization degree and acetylation degree are calculated based on the results of measurement in accordance with "Testing methods for polyvinyl butyral" of JIS K6728.

In the polymer film provided by the present invention, the pseudo specific gravity of the polyvinyl acetal resin contained in the first layer is 0.220 to 0.280, preferably 0.248 to 0.258. The pseudo specific gravity is measured according to JIS K6720.

The degree of polymerization described herein is an indicator for measuring the size of polymer molecules. The degree of polymerization is based on the number of repeating units, that is, the average number of repeating units contained in the polymer macromolecule chain. In the polymer film provided by the present invention, the degree of polymerization of the polyvinyl alcohol acetal resin contained in the first layer is greater than 1600 and less than 3850; preferably, its degree of polymerization is greater than 1750 and less than 3850; preferably, its degree of polymerization is 2000 to 3700, for example: 2000, 2200, 2400, 2600, 2800, 3000, 3200, 3400, 3500, 3600 or 3700.

The loss factor described herein is also called the loss coefficient, specifically the damping loss coefficient; its value is considered to be positively correlated with the sound insulation effect. The polymer film provided by the present invention has a damping loss coefficient greater than 0.25 measured at 20° C. according to the MIM mechanical impedance method of ISO 16940.

1 to 3 are cross-sectional views of layers presented by polymer films according to different embodiments of the present invention; wherein the polymer films of different embodiments have structural differences. FIG1 is a cross-sectional view of a layer stack of a polymer film 100A depicted according to an embodiment of the present invention. Referring to FIG1 , the polymer film 100A is a three-layer structure, wherein the upper and lower layers are both second layers 102, and between the two second layers 102 is a first layer 101. According to some embodiments of the present invention, the polymer film 100A may be an intermediate film of a laminated glass and is disposed between two glass plates; wherein the first layer 101 serves as an intermediate layer, and the second layer 102 serves as a protective layer. On the other hand, in terms of thickness, the thickness of the polymer film 100A is 0.5 to 2 mm, for example: 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2.0 mm; preferably, the thickness of the polymer film 100A is 0.8 mm; wherein the thickness of the first layer 101 is 0.11 to 0.15 mm, preferably 0.13 mm; and the thickness of the second layer 102 is 0.320 to 0.350 mm, preferably 0.335 mm.

FIG. 2 is a cross-sectional view of a polymer film 100B according to an embodiment of the present invention, which is similar to the polymer film 100A of the above embodiment; however, the difference is that the polymer film 100B provided in this embodiment is a two-layer structure, which is formed by stacking the first layer 101 and the second layer 102 .

FIG3 is a cross-sectional view of a polymer film 100C according to an embodiment of the present invention, which is similar to the polymer film 100A described above; however, the difference is that the polymer film 100C provided in this embodiment is provided with an additional first layer 101, which is attached to any of the upper/lower second layers 102. In addition to the above embodiments, those skilled in the art can add the first layer 101 or the second layer 102 to the polymer film 100C in an alternating manner according to needs without departing from the concept of the present invention, such as a four-layer structure, a five-layer structure, a six-layer structure, or a structure with more than six layers.

FIG. 4 is a flow chart of polymer film manufacturing according to an embodiment of the present invention. Referring to FIG. 4 , the polymer film manufacturing process provided by the present invention comprises at least steps S100 to S106. Specifically, in step S100, a first PVB resin and a plasticizer are mixed to form a first resin composition, wherein the operating temperature and the rotation speed during mixing can be adjusted according to known methods and requirements, and the detailed conditions are not limited by the present case. In step S102, a second PVB resin and a plasticizer are mixed to form a second resin composition, wherein the operating temperature and the rotation speed during mixing can also be adjusted according to known methods and requirements, and the detailed conditions are not limited by the present case. In step S104, the first resin composition and the second resin composition are respectively made into a first layer and a second layer; wherein the manufacturing method can be carried out by a known film preparation method, such as: extrusion molding or hot pressing molding. In step S106, the first layer and the second layer are combined to form a polymer film; wherein the manufacturing method can be carried out by a known film preparation method, such as: extrusion molding or hot pressing molding.

The polymer film prepared by the above process can be used as a test film to carry out the following various property measurements.

Determination of viscoelastic properties

The method used in this paper to determine viscoelastic properties includes at least the following steps: first, the film to be tested is cut into a circle with a diameter of 8 mm, and the film to be tested is placed in a constant temperature and humidity chamber for 24 hours, and the temperature and relative humidity are controlled to be maintained at 23°C and 55%, respectively; then, the film to be tested is placed in a rotational shear rheometer (Discovery Hybrid Rheometer II, DHR) (manufactured by TA Instrument) to analyze the viscoelastic properties by oscillation method, and the analysis conditions are as follows: the test temperature is reduced from 100°C to -10°C, and the cooling rate is 3°C/min; the oscillation frequency is set to 1Hz; the film to be tested is maintained at a strain of 1%; the clamp pressure is set to 1N. The loss factor and glass transition temperature of the film to be tested are obtained from the analysis results by the above method.

Determination of leakage from the membrane intermediate layer

The seepage of the middle layer of the diaphragm is an indicator of the structural integrity and plasticizer compatibility of a multi-layer diaphragm (at least three layers to define the middle layer); and it can be used as one of the factors that determine the sound insulation effect of the multi-layer diaphragm. If a diaphragm to be tested is determined to have a seepage of the middle layer of the diaphragm, it can be inferred that its plasticizer compatibility is low, and the diaphragm manufactured subsequently will have a problem of poor uniformity. Specifically, the method used in this article to determine the seepage of the middle layer of the diaphragm includes at least the following steps: First, the diaphragm to be tested is cut into a 4 cm circle, and then placed in a constant temperature and humidity chamber for 48 hours, and its temperature and relative humidity are controlled to remain at 23°C and 55% respectively; then, a positive force of 8N is applied to the diaphragm to be tested for 10 seconds, and then the middle layer is immediately observed with the naked eye to seep out.

Determination of film forming conditions

The film forming condition is an indicator of the structural integrity and plasticizer compatibility of a multilayer film (at least three layers to define the middle layer); and can be used as one of the factors determining the sound insulation effect of the multilayer film. If a film cannot be formed due to plasticizer seeping out of the middle layer after hot pressing, it can be inferred that the plasticizer compatibility is low. The method used in this article to determine the film forming condition is to make the polymer film provided by the present invention by hot pressing molding, and then observe with the naked eye whether there is plasticizer that cannot be absorbed seeping out from the middle layer.

Determination of loss coefficient

The method used in this paper to determine the loss coefficient is based on the MIM mechanical impedance method (Measurement of Mechanical Impedance) of ISO 16940. Specifically, the method includes at least the following steps: first, a film to be tested is sandwiched between two clean transparent float glasses with a length of 300 mm, a width of 25 mm, and a thickness of 2.3 mm, followed by pre-pressing and then positive pressing to obtain a laminated glass; wherein the pre-pressing condition is to use a hot press at 150°C for 3 minutes, and the positive pressing condition is to use an autoclave at 135°C and a pressure of 13 bar for 120 minutes. Next, on the 14th day after the laminated glass was prepared, it was placed in a constant temperature and humidity chamber for 2 hours, and its temperature and relative humidity were regulated to be maintained at 23°C and 55% respectively; further, the center of the laminated glass was fixed on a vibration shaker and oscillated at an ambient temperature of 20°C; further, the force and frequency of the oscillation were measured with an impedance head, and the experimental data were converted into loss coefficients with an analysis system. It should be clarified that the above loss coefficient is the first vibration mode calculated based on the half-power method; in general, it is believed that the higher the value, the better the sound insulation effect. For example, if the value of the loss coefficient is greater than 0.25 at 20°C, it means that it has a good sound insulation effect.

Examples 1 to 15

Here, the present invention provides polymer films of embodiments 1 to 15 according to the above content. Different embodiments are adjusted to produce different characteristics by using different parameters, and further analyze the film forming conditions of the polymer film (or intermediate film), the leakage conditions of the intermediate layer of the film sheet, and the characteristics of the loss coefficient. Regarding the film forming conditions of the intermediate film, if there is no plasticizer leakage, it is determined that the intermediate film can form a film, which is marked as "O"; if there is plasticizer leakage, it is determined that the intermediate film cannot form a film, which is marked as "X".

It should be explained that embodiments 1 to 15 all adopt a three-layer structure, and the second layer provided by the present invention is a protective layer disposed on the upper and lower sides, and the first layer provided by the present invention is a middle layer.

The preparation methods of the polymer films of Examples 1 to 15 are briefly described as follows:

First, 100 parts by weight of a first PVB resin and 60 to 90 parts by weight of a plasticizer (triethylene glycol bis(2-ethylhexanoate)) are fully mixed using a mixer to obtain a resin composition for an intermediate layer; 100 parts by weight of a second PVB resin and 37 to 43 parts by weight of a plasticizer (triethylene glycol bis(2-ethylhexanoate)) are fully mixed using a mixer to obtain a resin composition for a protective layer.

Next, the protective layer resin composition and the intermediate layer resin composition were heat-pressed at 150° C. using a heat press to form a protective layer (thickness: 0.335 mm) and an intermediate layer (thickness: 0.13 mm), respectively.

Finally, the middle layer was placed between two protective layers to form a three-layer structure. A hot press was used to preheat and press at 100°C for 1 minute, and then the temperature was raised to 150°C and hot-pressed for 3 minutes to obtain an intermediate film with a three-layer structure (thickness: 0.8 mm).

The detailed parameter definitions and characteristic analysis results of Examples 1 to 15 are shown in Table 1.

Table 1

As shown in Table 1, the ratio of the loss factor of the intermediate layer to the protective layer of Examples 1 to 15 is between 1.30 and 3.12, so the films made in these Examples all have good loss coefficients. Furthermore, if the hydroxyl content of the intermediate layer PVB resin is greater than 16.0 mol% and less than 30.6 mol%, there will be no leakage of the intermediate layer or failure of film forming, indicating high plasticizer compatibility, as shown in Examples 1 to 12.

Comparative Examples 1 to 5

Here, polymer films of Comparative Examples 1 to 5 are provided by a preparation method similar to that of Examples 1 to 15, and the differences are shown in the following table. The film forming condition of the intermediate film, the seepage condition of the intermediate layer of the diaphragm, and the characteristics of the loss coefficient are further analyzed. The analysis and evaluation methods are the same as those of Examples 1 to 15.

It should be noted that Comparative Examples 1 to 5 all adopt a three-layer structure, with protective layers disposed on the upper and lower sides and an intermediate layer disposed between the protective layers. Detailed parameter definitions and characteristic analysis results of Comparative Examples 1 to 5 are shown in Table 2.

Table 2

As shown in Table 2, the ratios of the loss factors of the intermediate layer and the protective layer of Comparative Examples 1 to 5 are all less than 1.30, and the loss coefficients of the polymer films of these comparative examples are all relatively low, so the sound insulation effects are all poor.

In summary, the present invention provides a polymer film, which is particularly suitable for an intermediate film of laminated glass, wherein when the ratio of the loss factor (tanδ) of the first layer to the second layer of the polymer film is between 1.30 and 3.12, the laminated glass made of the intermediate film has a good sound insulation effect; further, when its hydroxyl content ratio is greater than 16.0 mol% and less than 30.6 mol%, the film can have good film-forming properties.

The present invention has been described in detail above. However, what is described above is only the preferred embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. That is, all equivalent changes and modifications made according to the claims of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims (16)

1. A polymer film, wherein it comprises a polyvinyl acetal resin and a plasticizer; and is also provided with

The polymer film comprises at least a first layer and a second layer, the loss factors of the first layer and the second layer are different

The ratio of the loss factor of the first layer to the second layer is 1.30 to 3.12.

2. The polymer film according to claim 1, wherein the plasticizer is 50 to 90 parts by weight based on 100 parts by weight of the polyvinyl acetal resin of the first layer.

3. The polymer film according to claim 2, wherein the polyvinyl acetal resin of the first layer has a hydroxyl group content ratio of more than 16.0mol% and less than 30.6mol%.

4. The polymer film of claim 3, wherein the first layer of polyvinyl acetal resin has a degree of polymerization greater than 1750 and less than 3850.

5. The polymer film of claim 4, wherein the first layer of the polyvinyl acetal resin has an acetyl content of less than 20mol%.

6. The polymer film of claim 5, wherein the glass transition temperature of the first layer is from-7 to 6 ℃.

7. The polymer film of claim 6, wherein the first layer has a loss factor of 0.70 to 1.38.

8. The polymer film according to any one of claims 1 to 7, wherein the plasticizer is 30 to 60 parts by weight per 100 parts by weight of the polyvinyl acetal resin of the second layer.

9. The polymer film according to claim 8, wherein the polyvinyl acetal resin of the second layer has a hydroxyl group content ratio of 25mol% to 31mol%.

10. The polymer film of claim 9, wherein the glass transition temperature of the second layer is 25 to 35 ℃.

11. The polymer film of claim 10, wherein the second layer has a loss factor of 0.37 to 0.94.

12. The polymer film according to claim 11, wherein the polymer film has a three-layer structure, and wherein the upper and lower layers are the second layer sandwiching the first layer.

13. The polymer film of claim 11, wherein the damping loss factor at 20 ℃ according to the mechanical impedance method of ISO 16940 is greater than 0.25.

14. The polymer film according to claim 11, wherein the thickness thereof is 0.5 to 2mm as an intermediate film for laminated glass.

15. The polymer film of claim 14, wherein the thickness is 0.8mm and the thickness of the second layer/first layer/second layer is 0.335mm/0.13mm/0.335mm.

16. The polymer film of claim 15, wherein the polyvinyl acetal is polyvinyl butyral.

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