CN116254064A - Polymer film - Google Patents

Abstract

The present invention relates to a polymer film, which comprises polyvinyl acetal resin and a plasticizer; wherein, the polymer film is one or more layers, and the temperature at which the minimum value of the loss factor of the polymer film appears is 40°C to 60°C. The polymer film provided by the invention has good fluidity and processability.

Description

polymer film

【Technical field】

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

【Background technique】

Polymer films are widely used in today's society, and their materials are quite diverse. Polymer films have good film-forming properties, and can be adjusted according to raw materials or manufacturing processes to have high transparency, elasticity, toughness, strong alkali resistance, and oil resistance. Excellent properties such as flexibility, flexibility, weather resistance and low temperature impact resistance. Polyvinyl acetal resin, a common material for polymer film, has a special chemical structure, so it has excellent adhesion to glass, metal, ceramic powder, plastic, leather and wood; in addition, polyvinyl acetal resin Vinyl acetal resin has good dispersibility for pigments and dyes, and has excellent compatibility with various resins.

At the application level, the polymer film made of polyvinyl acetal resin can exist in various forms such as a single-layer film, a multi-layer film, or an interlayer film sandwiched between glasses. However, before being made into a final product, polyvinyl acetal resin films need to go through a lot of processing steps, such as stretching or cutting and other processes involving deformation. Accordingly, whether the polyvinyl acetal resin film has excellent processability becomes an important index.

Specifically, the processability of a polymer is highly correlated with its viscoelastic properties; the so-called viscoelastic properties refer to the reversible and irreversible modulus of deformation when a material is deformed. Further, the parameters related to viscoelastic properties include loss factor (tanδ) value and corresponding glass transition temperature (glass transition temperature, Tg). The so-called tanδ also refers to loss factor, damping factor or loss tangent, which is used to express The damping characteristic in the viscoelastic properties of a material, and can be equivalent to the ratio of the loss modulus (loss modulus, G") of the material to the storage modulus (storage modulus, G'); relatively, the loss factor corresponds to the temperature The peak value of the wave is the glass transition temperature, which can be regarded as the temperature at which a substance can reversibly change between the glass state (meaning that the material is in a state of low fluidity) and the high elastic state (meaning that the material is in a state of high fluidity and softness) .

【Content of invention】

The Summary of the Invention is intended to provide a simplified summary of the invention to enable readers to have a basic understanding of the invention. This summary is not an extensive overview of the invention, and it is not intended to identify key or critical elements of the embodiments of the invention or to delineate the scope of the invention.

The present inventors have found that the viscoelastic properties exhibited by the polymer film under the temperature conditions during its processing have a further correlation with its processability, and should be able to be obtained by controlling the viscoelastic properties under the temperature conditions. Polymer film with better processability. As an interlayer film for laminated glass, polyvinyl acetal film will go through the process of film stretching, which will stretch the film into the desired shape. If the film is too hard, it will be difficult to stretch the film at the rear end because it is difficult to stretch; if it is too soft, the texture will collapse during the film stretching process. Therefore, the viscoelastic properties of the film at 40 to 60°C are the key to whether the processing is smooth key. Accordingly, the present invention improves the flowability and processability of polymer films by defining the temperature range in which their loss tangent (tan δ) minima occurs.

Specifically, the present invention provides a polymer film, which includes polyvinyl acetal resin and a plasticizer, and the polymer film is one or more layers, and the minimum value of the loss factor of the polymer film appears The temperature is 40°C to 60°C.

According to an embodiment of the present invention, the minimum value of the loss factor is 0.13 to 0.19.

According to an embodiment of the present invention, in the case of one layer, the temperature at which the minimum value of the loss factor occurs is greater than its glass transition temperature; or in the case of multiple layers, the temperature at which the minimum value of the loss factor occurs is greater than its maximum glass transition temperature temperature.

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

According to an embodiment of the present invention, the polymer film has a thickness of 0.2 mm to 2 mm.

According to an embodiment of the present invention, the thermal shrinkage (%) ((length before heating−length after heating)/length before heating×100) of the polymer film after heat treatment at 50° C. for 1 hour is 2% to 5%.

According to an embodiment of the present invention, the elongation of the polymer film measured according to ASTM D412 is 220% to 300%.

According to an embodiment of the present invention, in the case of one layer, the hydroxyl content ratio of the polyvinyl acetal resin of the polymer film is 27mol% to 31mol%, and/or the polyvinyl acetal resin The degree of aldehyde is 68 mol% to 72 mol%.

According to an embodiment of the present invention, in the case of one layer, wherein the polyvinyl acetal resin of the polymer film is 100 parts by weight, the plasticizer is 30 to 60 parts by weight.

According to an embodiment of the present invention, in the case of one layer, the polymer film is a head-up display (HUD, head-up display) film.

According to an embodiment of the present invention, the polymer film has a thick end and a thin end that is thinner than the thick end.

According to an embodiment of the present invention, in the case of multiple layers, the polymer film has a three-layer structure, the upper and lower layers are protective layers and an intermediate layer is sandwiched.

According to an embodiment of the present invention, the polyvinyl acetal resin of the protective layer has a hydroxyl content ratio of 27 mol% to 31 mol%, and/or an acetalization degree of 68 mol% to 72 mol%.

According to an embodiment of the present invention, based on 100 parts by weight of the polyvinyl acetal resin of the protective layer, the amount of the plasticizer is 30 to 60 parts by weight.

According to an embodiment of the present invention, the polyvinyl acetal resin of the intermediate layer has a hydroxyl content ratio of 22 mol% to 27 mol%, and/or an acetalization degree of 62 mol% to 68 mol%.

According to an embodiment of the present invention, based on 100 parts by weight of the polyvinyl acetal resin of the middle layer, the amount of the plasticizer is 60 to 90 parts by weight.

According to an embodiment of the present invention, the polymer film is used as an interlayer film for laminated glass, and its thickness is 0.5 to 2 mm.

According to an embodiment of the present invention, the thickness of the polymer film is 0.8mm, and the thickness of the protective layer/intermediate layer/protective layer is 0.335mm/0.13mm/0.335mm.

The advantages provided by the present invention are: based on the definition of the above-mentioned features, the polymer film provided by the present invention has better processability and fluidity.

【Description of drawings】

In order to make the above and other objects, features, advantages and embodiments of the present invention more understandable, the accompanying drawings are described as follows:

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

FIG. 4 to FIG. 5 are flow charts illustrating the fabrication of polymer films according to different embodiments of the present invention.

In accordance with common practice, the various features and components in the drawings are not drawn to scale, but are drawn in order to best represent the specific features and components relevant to the invention. In addition, the same or similar component symbols refer to similar components and components in different drawings.

【Detailed ways】

In order to make the description of the present invention more detailed and complete, the following provides an illustrative description of the implementation and specific embodiments of the present invention, but this is not the only form for implementing or using the specific embodiments of the present invention. In this specification and the appended claims, unless the context specifies otherwise, "a" and "the" can also be interpreted as plural. In addition, in this specification and the scope of the appended patent application, unless otherwise specified, "set on something" can be regarded as directly or indirectly contacting the surface of something by sticking or other forms, and the surface of the The definition should be judged according to the context/paragraph semantics of the content of the description and the common knowledge in the field to which this description belongs.

Although the numerical ranges and parameters used to define the present invention are approximate numerical values, the relevant numerical values in the specific examples are presented here as precisely as possible. Any numerical value, however, inherently inherently contain standard deviations resulting from their individual testing methodology. As used herein, "about" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a particular value or range. Alternatively, the term "about" means that the actual value falls within an acceptable standard error of the mean, as considered by one of ordinary skill in the art to which this invention pertains. Therefore, unless otherwise stated to the contrary, the numerical parameters disclosed in this specification and the appended patent claims are approximate values, and may be changed as required. At least these numerical parameters should be understood as the value obtained by applying the normal rounding method to the indicated effective digits.

The invention provides a polymer film comprising 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 above-mentioned polyvinyl alcohol can be obtained by saponifying polyvinyl ester, and its polyethylene The saponification degree of the alcohol is usually in the range of 70 mole % to 99.9 mole %, for example: 70 mole %, 75 mole %, 80 mole %, 85 mole %, 90 mole %, 95 mole %, 99 mole % or 99.9 mole % . The above-mentioned aldehydes usually can be aldehydes with a carbon number of 1 to 10, such as: formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, 2-ethylbutyraldehyde, n-hexanal, n-octylaldehyde, N-nonanal, n-decylaldehyde and benzaldehyde, etc.; preferably, the aldehyde is propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-hexanal or n-valeraldehyde; more preferably propionaldehyde, n-butyraldehyde or isobutyraldehyde aldehyde. According to an embodiment of the present invention, the polyvinyl acetal is polyvinyl butyral (Polyvinyl Butyral, PVB).

On the other hand, the plasticizer is also called plasticizer, which is usually used in combination with polyvinyl acetal resin to affect the viscoelastic properties of the material. Specifically, the plasticizer is non-limitingly selected from the group consisting of monobasic acid esters, polybasic acid esters, organic phosphoric acid, and organic phosphorous acid; more specifically, the plasticizer is selected from triethylene glycol bis(2 -Ethylhexanoate) (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, adipic acid Hexylcyclohexyl ester, diisononyl adipate, heptylnonyl adipate, dibutyl sebacate, bis[2-(2-butoxyethoxy)ethyl adipate], Polyadipate, Propylene Glycol Dibenzoate, Dipropylene Glycol Dibenzoate, Tripropylene Glycol Dibenzoate, Polypropylene Glycol Dibenzoate, 2,2,4-Trimethyl-1,3 -Pentylene glycol dibenzoate, isodecyl benzoate, 2-ethylhexyl benzoate, diisononyl phthalate, dibutoxyethyl terephthalate, castor oil, castor The group consisting of methyl sesoleate, soybean oil, and epoxidized soybean oil.

The polymer film provided by the present invention has a one-layer or multi-layer structure, and the temperature at which the minimum value of the loss factor appears is 40°C to 60°C, such as but not limited to: 42.28°C, 48.29°C, 49.77°C, 51.43°C, 52.23°C °C, 54.21 °C, 56.18 °C, 58.27 °C, or 59.14 °C.

The so-called loss factor is tanδ (or loss factor, damping factor, loss tangent), which is used to express the damping characteristics in the viscoelastic properties of materials, and can be equivalent to the loss modulus of materials (or loss modulus, viscoelasticity modulus, lossmodulus, G") to the ratio of the storage modulus (or elastic modulus, storage modulus, G'). Without being limited by a specific theory, the loss factor will have the lowest value, and this low point represents Energy is mainly stored; but after the temperature of this low point, the energy is gradually turned into consumption, and the viscosity begins to increase at this time. Therefore, this low point can be adjusted to meet the requirements of the processing process, for example: if this low point If it is lower than the processing temperature, the film will be broken because the film is too soft; on the contrary, if the low point is greater than the processing temperature, it will be difficult to expand the film because the film is too tough.

According to some embodiments of the present invention, the minimum value of the loss factor is 0.13 to 0.19, such as but not limited to: 0.138, 0.141, 0.144, 0.149, 0.151, 0.174, 0.177, 0.179 or 0.181. According to some embodiments of the present invention, the polymer film is a single-layer film structure and has a Tg, and the temperature at which the minimum value of the loss factor occurs is greater than the Tg; according to other embodiments of the present invention, the The polymer film has a structure of a multi-layer film body and has a maximum Tg, and the temperature at which the minimum value of the dissipation factor occurs is greater than the maximum Tg. As used herein, the so-called Tg refers to the glass transition temperature, which refers to the reversibility of a substance between the glassy state (meaning that the material is in a low fluidity state) and the high elastic state (meaning that the material is in a high fluidity and soft state) The transformation temperature; further, the temperature at which the loss factor produces a peak value is the glass transition temperature.

The hydroxyl group content ratio of the polyvinyl acetal resin herein refers to a mole fraction obtained by dividing the amount of ethylidene groups bonded to hydroxyl groups by the total amount of ethylidene groups in the main chain in percentage. The degree of acetalization (or called the degree of acetalization) of the polyvinyl acetal resin described herein refers to the amount expressed as a percentage of the ethylenic group bonded to the acetal group divided by the total ethylenic group amount of the main chain. out the mole fraction. The degree of acetylation (or the degree of acetylation) of the polyvinyl acetal resin described herein is a value expressed as a percentage, which is the amount of ethylidene groups bonded to hydroxyl groups and The mole fraction obtained by dividing the amount of ethylenyl groups bonded to the acetal group by the total amount of ethylenyl groups in the main chain.

The above-mentioned hydroxyl group content ratio, degree of acetalization, and degree of acetylation are calculated based on the measurement results of "Molar polyvinyl butyral test method" of JIS K6728.

1 to 3 are cross-sectional views of polymer films according to different embodiments of the present invention. The different embodiments respectively express the different structural aspects of the polymer film of the present invention; specifically, the polymer film provided by the present invention can be a single-layer film structure (as shown in Figure 1), a three-layer film structure ( As shown in Figure 2) and wedge-shaped membrane structure (as shown in Figure 3). However, those skilled in the art can adjust or modify the contents of the structural aspects as required without departing from the central idea of the present invention.

Monolayer film

Referring to FIG. 1 , the present invention provides a polymer film 100A, which has a layer 101. The thickness of the layer body 101 is preferably 0.2 to 2 mm, more preferably 0.38 to 1.52 mm, such as but not limited to: 0.38, 0.76 or 1.52 mm. The glass transition temperature of the layer 101 may be 10 to 35°C, preferably 25 to 35°C, more preferably 28 to 33°C, but the present invention is not limited thereto.

In the polymer film 100A provided by the present invention, the polyvinyl acetal resin contained in the layer body 101 has a hydroxyl content ratio of 26 to 31 mol%, preferably 27.1 to 29.6 mol%, such as but not limited to: 27.1, 27.4, 27.5 or 29.6 mol%. The acetalization degree of the polyvinyl acetal resin contained in the layer body 101 is 68 to 73 mol%, preferably 69.4 to 71.9 mol%, such as but not limited to: 69.4, 71.5, 71.6 or 71.9 mol%. The acetylation degree of the polyvinyl acetal resin contained in the layer body 101 is 0.1 to 3.0 mol%, preferably 1.0 mol%, but the present invention is not limited thereto.

In the polymer film 100A provided by the present invention, the pseudo specific gravity of the polyvinyl acetal resin contained in the layer body 101 may be 0.200 to 0.300, preferably 0.240 to 0.260, more preferably 0.249 to 0.258, But the present invention is not limited thereto. The pseudo specific gravity described here is measured based on JIS K6720.

In the polymer film 100A provided by the present invention, the number average molecular weight (Mn) of the polyvinyl acetal resin contained in the layer body 101 may be 90,000 to 125,000, preferably 105,000 to 120,000, more preferably 106,250 to 115,200, but the present invention is not limited thereto.

Three-layer film

Please refer to Fig. 2, the present invention provides a polymer film 100B here, and its structure is to present an intermediate layer 102 to be sandwiched between the aspect between two upper and lower protective layers 104; Yet, except this three-layer structure, this A person with ordinary knowledge in the field can add a fourth, fifth or sixth layer according to requirements; and preferably, the intermediate layer and the protective layer are also interleaved and laminated. Specifically, the thickness of the intermediate layer 102 is preferably 0.11 to 0.15mm, more preferably 0.13mm; the thickness of the protective layer 104 is preferably 0.32 to 0.35mm, more preferably 0.335mm; and the polymer The thickness of the film 100B is preferably 0.5 to 2 mm, more preferably 0.75 to 0.85 mm, for example: 0.75, 0.76, 0.77, 0.78, 0.8, 0.82 or 0.85 mm. In a preferred embodiment, the polymer film has a three-layer structure, the upper and lower layers are protective layers and an intermediate layer is sandwiched, which is used as an intermediate film for laminated glass.

In the polymer film 100B provided by the present invention, the glass transition temperature of the intermediate layer 102 may be -10 to 6°C, preferably -8 to 0°C, more preferably -7 to -2°C, but The present invention is not limited thereto; the glass transition temperature of the protective layer 104 may be 10 to 35°C, preferably 25 to 35°C, more preferably 28 to 33°C, but the present invention is not limited thereto. limited.

In the polymer film 100B provided by the present invention, the polyvinyl acetal resin contained in the intermediate layer 102 has a hydroxyl content ratio of 22 to 27 mol%, preferably 23.8 to 26.2 mol%, such as but not limited to: 23.8, 24.9 or 26.2 mol%. The acetalization degree of the polyvinyl acetal resin contained in the intermediate layer 102 is 62 to 68 mol%, preferably 63.3 to 67.6 mol%, such as but not limited to: 63.3, 63.7 or 67.6 mol%. The acetylation degree of the polyvinyl acetal resin contained in the middle layer 102 is 7 to 13 mol%, such as but not limited to: 8.6, 10.5 or 11.4 mol%, but the present invention is not limited thereto. On the other hand, the polyvinyl acetal resin contained in the protective layer 104 has a hydroxyl content ratio of 26 to 31 mol%, preferably 27.4 to 30.1 mol%, such as but not limited to: 27.4, 27.8 or 30.1 mol%. The acetalization degree of the polyvinyl acetal resin contained in the protective layer 104 is 68 to 73 mol%, preferably 68.9 to 71.6 mol%, such as but not limited to: 68.9, 71.2, or 71.6 mol%. The acetylation degree of the polyvinyl acetal resin contained in the protective layer 104 is 0.1 to 3.0 mol%, preferably 1.0 mol%, but the present invention is not limited thereto.

In the polymer film 100B provided by the present invention, the polyvinyl acetal resin contained in the intermediate layer 102 may have a pseudo specific gravity of 0.200 to 0.300, preferably 0.240 to 0.260, more preferably 0.247 to 0.258, But the present invention is not limited thereto; the pseudo specific gravity of the polyvinyl acetal resin contained in the protective layer 104 can be 0.200 to 0.300, preferably 0.240 to 0.260, more preferably 0.251 to 0.257, but this The invention is not limited thereto.

In the polymer film 100A provided by the present invention, the number average molecular weight (Mn) of the polyvinyl acetal resin contained in the intermediate layer 102 may be 100,000 to 280,000, preferably 120,000 to 250,000, more preferably 150,000 to 225,000, but the present invention is not limited thereto; the number average molecular weight (Mn) of the polyvinyl acetal resin contained in the protective layer 104 can be 90,000 to 125,000, preferably 105,000 to 120,000, more preferably The range is 107,950 to 112,000, but the present invention is not limited thereto.

wedge membrane

Please refer to FIG. 3 , where the present invention provides a polymer film 100C. According to some embodiments of the present invention, the polymer film 100C may be used as a head-up display (HUD) film. Specifically, in order to avoid overlapping projected images when the polymer film 100C is used as a HUD film, two ends of the film body are respectively provided with a thick end and a thin end that is thinner than the thick end. The thin end has a thickness T ₁ , and the thick end has a thickness T ₂ ; the thickness T ₁ is 0.7 to 0.8 mm, preferably 0.76 mm; and the thickness T ₂ is 1.4 to 1.5 mm, preferably is 1.45mm. Furthermore, the polymer film 100C illustrates a wedge-shaped film structure as a whole, and its width W ₁ is 1200 mm.

In the polymer film 100C provided by the present invention, the scope of the polyvinyl acetal resin contained in the polymer film 100C is similar to the content of the above-mentioned embodiment of the single-layer film, and the polyvinyl acetal resin contained in the polymer film 100C The hydroxyl content ratio of the aldehyde resin is 26 to 31 mol%, preferably 28.3 to 28.7 mol%, such as but not limited to: 28.3 or 28.7 mol%; the acetal of the polyvinyl acetal resin contained in the polymer film 100C The acetylation degree (mol%) is 68 to 73mol%, preferably 70.3 to 70.7mol%, such as but not limited to: 70.3 or 70.7mol%; and the acetylation degree of the polyvinyl acetal resin contained in the polymer film 100C (mol%) is 0.1 to 3.0 mol%, preferably 1.0 mol%, but the present invention is not limited thereto.

Polymer film manufacturing process

4 to 5 are flow charts showing different embodiments of the polymer film fabrication of the present invention. Please refer to FIG. 4 first. The polymer film manufacturing process provided here is used to manufacture the above-mentioned single-layer film and wedge-shaped film; the process at least includes steps S100 to S102.

Specifically, in step S100, a polyvinyl acetal resin and a plasticizer are kneaded to form a resin composition. Wherein, the polyvinyl acetal resin is based on 100 parts by weight, the plasticizer is preferably 30 to 60 parts by weight; more preferably, the plasticizer is 35 to 45 parts by weight, for example: 35, 36, 37, 38 , 39, 40, 41, 42, 43, 44 or 45 parts by weight. On the other hand, the operating temperature and rotation speed during kneading can be adjusted according to conventional methods and requirements, and the detailed conditions are not limited by this case.

In step S102, the resin composition is made into a polymer film. Wherein, the manufacturing method can be carried out by conventional film preparation methods, such as extrusion molding or thermocompression molding and other methods. Further, in this step, detailed adjustments can be made according to the shape of the fabricated polymer film; for example, a single-layer film or a wedge-shaped film with different geometric parameters can be produced through detailed adjustments.

Referring again to FIG. 5 , the polymer film manufacturing process provided here is used to make the above-mentioned three-layer film; the process at least includes steps S200 to S206 .

Specifically, in step S200, the first polyvinyl acetal resin and the plasticizer are kneaded to form a first resin composition. Wherein, the first polyvinyl acetal resin is calculated as 100 parts by weight, the plasticizer is preferably 60 to 90 parts by weight; more 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. On the other hand, the operating temperature and rotation speed during kneading can be adjusted according to conventional methods and requirements, and the detailed conditions are not limited by this case.

In step S202, the second polyvinyl acetal resin and plasticizer are kneaded to form a second resin composition; wherein, based on 100 parts by weight of the polyvinyl acetal resin, the plasticizer is preferably 30 to 60 parts by weight; more preferably, the plasticizer is 35 to 45 parts by weight, for example: 35, 36, 37, 38, 39, 40, 41, 42, 43, 44 or 45 parts by weight. On the other hand, the operating temperature and rotation speed during kneading can also be adjusted according to conventional methods, and the detailed conditions are not limited by this case.

In step S204, the first resin composition and the second resin composition are respectively made into the first layer and the second layer; wherein, the manufacturing method can be carried out by conventional film preparation methods, such as extrusion molding or thermocompression molding and other methods. In step S206, the first layer and the second layer are combined to form a polymer film; wherein, the first layer serves as an intermediate layer, and the second layer serves as a protective layer. On the other hand, the manufacturing method can also adopt conventional film preparation methods, such as extrusion molding or thermocompression molding and other methods. According to at least one embodiment, step S204 and step S206 can be to extrude the second resin composition (as a protective layer) and the first resin composition (as an intermediate layer) with a T-type die head co-extrusion An intermediate film with a three-layer structure is produced, wherein the structure of the intermediate film is protective layer/intermediate layer/protective layer.

Determination of molecular weight of polyvinyl acetal resin

The molecular weight distribution of the polyvinyl acetal resin was measured by gel permeation chromatography (GPC), wherein the polyvinyl acetal resin was dissolved in tetrahydrofuran (tetrahydrofuran, THF), and GPC was carried out under the following conditions Analyze and calculate its molecular weight as the ratio of the area of the corresponding polystyrene standard (Waters PS STD).

Device: Waters 1515PUMP system

Detector: Waters 2414RI

Eluting condition: 1.0 milliliter/minute (mL/min), THF

Columns: Waters Styragel HR5 THF, Waters Styragel HR4 THF, Waters Styragel HR3 THF, Waters Styragel HR1 THF

The polymer film manufactured through the above process can be used as a film to be tested for the following various characteristic measurements.

Determination of viscoelastic properties

The method for measuring viscoelastic properties in this paper at least includes the following steps: First, cut the membrane to be tested into a circle with a diameter of 8mm, and place the membrane to be tested in a constant temperature and humidity box 24 Hours, the temperature and relative humidity were further adjusted and maintained at 23°C and 55%, respectively. It should be particularly noted that in the step of cutting into a circle, the cutting is carried out at the middle of the width direction of the film to be tested.

Next, place the membrane to be tested in a rotational shear rheometer (Discovery Hybrid Rheometer II, DHR) (manufactured by TA Instrument) to analyze the viscoelastic properties by the oscillation method. The analysis conditions are as follows: the test temperature decreases from 100 ° C to to -20°C, and the cooling rate is 3°C/min; the oscillation frequency is set to 1Hz; the strain of the diaphragm to be tested is maintained at 1%; the clamp pressure is set to 1N. The dissipation factor and glass transition temperature of the membrane to be tested are obtained from the analysis results by the above method.

Determination of heat shrinkage

The method used in this paper to determine thermal shrinkage is based on the following instruments:

Heating Oven (Model: Binder FD-115W)

thermal cycle oven

Ruler (accuracy is 1mm)

The method for determining thermal shrinkage rate in this paper at least includes the following steps: cutting the film to be tested into a square with a side length of 17 cm, and marking a 15 cm square marking line in the film to be tested; After the film to be tested was suspended in an oven set at 50°C for 1 hour, it was taken out and placed at room temperature for 1 hour; finally, the thermal shrinkage of the film to be tested was measured.

The calculation method for thermal shrinkage rate is: thermal shrinkage rate (%)=(length before heating−length after heating)/length before heating*100. Without being bound by a specific theory, the higher the calculated heat shrinkage value, the more the film to be tested tends to be in a state of high fluidity and softness; and the lower the heat shrinkage value, the more the film to be tested is The sheet tends to be in a hard state with low fluidity. According to at least one embodiment, under heat treatment at 50°C for 1 hour, if the thermal shrinkage value of the film to be tested is in the range of 2-5%, then the film to be tested can be considered to have good processability .

Determination of elongation

The method used to measure elongation in this paper follows the ASTM D412 test specification, and the instrument used is the AI-7000M tensile testing machine manufactured by GOTECH. Specifically, the method at least includes the following steps: placing the film to be tested in an environment with a relative humidity of 23% and a temperature of 23° C. for 2 hours.

The calculation method for elongation is: elongation (%)=(length after stretching−length before stretching)/length before stretching*100. According to at least one embodiment, if the elongation value of the film to be tested is in the range of 220% to 300%, the film to be tested can be considered to have good processability. If the elongation is greater than 300%, it will be easily deformed during the stretching process; if the elongation is less than 220%, it will be difficult to stretch in use, resulting in difficult stretching.

Examples 1 to 9

Here, the present invention provides the polymer films of Examples 1 to 9 according to the above content. Different examples are adjusted and made with different parameters to produce different characteristics; further, for the viscoelastic properties and thermal shrinkage of the polymer films And the characteristics of elongation were analyzed. The detailed parameter definitions and characteristic analysis results of Examples 1 to 9 are shown in Table 1.

The preparation method of the polymer film of embodiment 1 to 9 is briefly described as follows:

Prepare the resin composition for the protective layer: use a kneader to fully knead 100 parts by weight of the first polyvinyl acetal resin (exemplarily use PVB resin) and 35 to 45 parts by weight of plasticizer (exemplarily use 3GO) , to obtain a resin composition for a protective layer.

Prepare the resin composition for the middle layer: use a kneader to fully knead 100 parts by weight of the second polyvinyl acetal resin (exemplary use of PVB resin) and 60 to 70 parts by weight of plasticizer (exemplary use of 3GO) , to obtain a resin composition for an intermediate layer.

Preparation of film body: Examples 1 to 4 use an extruder to extrude the resin composition for the protective layer into a single-layer film with a thickness of 0.38 to 1.52 mm; ) form, using an extruder to extrude the above-mentioned resin composition into one end thick and one end thin, wherein the thickness of the thick end and the thin end are respectively 1.45mm and 0.76mm, and the width of the HUD film is about 1200mm; and the embodiment 7 to Series 9 extrudes the resin composition for the protective layer and the resin composition for the intermediate layer through a T-die to form a three-layer film with a thickness of 0.8mm, and its structure is protective layer/intermediate layer/ Protective layer (thickness: 0.335mm/0.13mm/0.335mm).

Comparative Examples 1 to 8

The polymer films of Examples 1 to 9 were compared in a preparation method similar to that of Examples 1 to 9, and the differences are shown in Table 2; further, for the viscoelastic properties, thermal shrinkage and elongation of the polymer films Characteristic is analyzed, and analysis and evaluation method are identical with embodiment 1 to 9.

It should be clarified that Comparative Examples 1 to 4 are in the form of a single-layer film; Comparative Examples 5 and 6 are in the form of a wedge-shaped film (i.e. a HUD film); and Comparative Examples 7 to 8 are in the form of a three-layer film (with a The middle layer is sandwiched between the upper and lower protective layers). The detailed parameter definitions and characteristic analysis results of Comparative Examples 1 to 8 are shown in Table 2.

Table 1

Table 2

It can be seen from Table 1 and Table 2 that whether the polymer films in Examples 1 to 9 are single-layer films or multi-layer films, the temperature at which the lowest value of the loss factor of the polymer film appears is 40°C to 60°C, so that the implementation The polymer films of Examples 1 to 9 exhibited better fluidity and processability than the polymer films of Comparative Examples 1 to 8. It can be further understood from Table 2 that the temperature at which the lowest loss factor values of Comparative Examples 1, 3, 5, and 7 appear are all less than 40°C, and their thermal shrinkage rates are all greater than 5%, and their elongation rates are all greater than 300%, showing that comparative examples The polymer films of Examples 1, 3, 5, and 7 are too soft, and are easy to be deformed or broken during film stretching; while the lowest values of loss factors of Comparative Examples 2, 4, 6, and 8 all occur at temperatures greater than 60°C. The heat shrinkage ratios of the polymer films of Comparative Examples 2, 4, 6 and 8 are all less than 2%, and the elongation rates are all less than 220%, which shows that the polymer films of Comparative Examples 2, 4, 6 and 8 are too tough, making it difficult to stretch the film.

In summary, the present invention provides a polymer film comprising polyvinyl acetal resin and a plasticizer; wherein the polymer film is one or more layers, and the minimum value of the loss factor of the polymer film appears The temperature is 40°C to 60°C. The polymer film provided by the invention has good fluidity and processability.

Unless otherwise defined herein, scientific and technical terms used in connection with this application shall have the ordinary meaning as understood by those of ordinary skill in the art. Further, unless otherwise required by context, words in the singular shall include pluralities and words in the plural shall include the singular.

The present invention has been described in detail above, but the above is only a preferred embodiment of the present invention, and should not limit the scope of the present invention with this, that is, all equivalent changes made according to the patent scope of the present invention and modification, all should still belong to the scope of patent coverage of the present invention.

【Symbol Description】

100A～100C: polymer film

101: layer body

102: middle layer

104: protective layer

W ₁ : width

T ₁ , T ₂ : Thickness

S100～S102, S200～S206: steps.

Claims (18)

1. A polymer film, which comprises polyvinyl acetal resin and a plasticizer, and the polymer film is one or more layers, and the temperature at which the minimum value of the loss factor of the polymer film occurs is from 40°C to 60°C. 2. The polymer film of claim 1, wherein the loss factor minimum value is 0.13 to 0.19. 3. The polymeric film of claim 2 , the temperature at which said dissipation factor minima occurs greater than its glass transition temperature in the case of a single layer; or the temperature at which said dissipation factor minima occurs in the case of a multilayer greater than its maximum glass transition temperature. 4. The polymer film of claim 1, wherein the polyvinyl acetal resin is polyvinyl butyral. 5. The polymer film according to claim 1, which has a thickness of 0.2 mm to 2 mm. 6. The polymer film according to claim 1, which has a heat shrinkage rate of 2% to 5% upon heat treatment at 50°C for 1 hour. 7. The polymer film of claim 1, which has an elongation measured according to ASTM D412 of 220% to 300%. 8. The polymer film according to claim 1, wherein in the case of one layer, the hydroxyl content ratio of said polyvinyl acetal resin of said polymer film is 27 mol% to 31 mol%, and/or said polyethylene The degree of acetalization of the alcohol acetal resin is 68 mol% to 72 mol%. 9. The polymer film according to claim 1, wherein said plasticizer is 30 to 60 parts by weight based on 100 parts by weight of said polyvinyl acetal resin of said polymer film in the case of one layer. 10. The polymer film according to any one of claims 1 to 9, which in the case of one layer is a film for a head-up display. 11. The polymer film of claim 10 having a thick end and a thin end having a thickness less than said thick end. 12. The polymer film according to any one of claims 1 to 7, in the case of multiple layers, it is a three-layer structure, the upper and lower layers are protective layers and an intermediate layer is sandwiched. 13. The polymer film according to claim 12, wherein said polyvinyl acetal resin of said protective layer has a hydroxyl content ratio of 27 mol% to 31 mol%, and/or a degree of acetalization of 68 mol% to 72 mol%. 14. The polymer film according to claim 12, wherein said polyvinyl acetal resin of said protective layer is 30 to 60 parts by weight based on 100 parts by weight of said plasticizer. 15. The polymer film according to claim 12, wherein said polyvinyl acetal resin of said intermediate layer has a hydroxyl content ratio of 22 to 27 mol%, and/or an acetalization degree of 62 to 68 mol%. 16. The polymer film according to claim 12, wherein said polyvinyl acetal resin of said intermediate layer is 60 to 90 parts by weight based on 100 parts by weight of said plasticizer. 17. The polymer film according to claim 12, which is an interlayer film for laminated glass and has a thickness of 0.5 to 2 mm. 18. The polymer film according to claim 17, having a thickness of 0.8mm, and the thickness of the protective layer/interlayer/protective layer is 0.335mm/0.13mm/0.335mm.

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