Polyvinyl butyral resin, laminated glass intermediate film and laminated glass

Abstract

The invention relates to the technical field of laminated glass intermediate films, in particular to polyvinyl butyral resin, a laminated glass intermediate film and laminated glass. According to the polyvinyl butyral resin disclosed by the invention, the polyvinyl butyral resin is formed by condensing n-butyraldehyde, a cyclic polyaldehyde compound and polyvinyl alcohol under an acid catalysis condition; the cyclic polyaldehyde compound comprises at least two aldehyde groups; the content of the polyvinyl alcohol is 100 parts by weight, the content of the n-butyraldehyde is 45 to 60 parts by weight, and the content of the cyclic polyaldehyde compound is 0.09 to 0.29 part by weight. According to the polyvinyl butyral resin, the laminated glass intermediate film and the laminated glass disclosed by the invention, a small amount of cyclic polyaldehyde compound is added in the process of synthesizing the polyvinyl butyral resin, so that the problem that the transverse performance and the longitudinal performance of the polyvinyl butyral resin are different due to molecular chain orientation can be reduced; therefore, the problem that the transverse performance and the longitudinal performance of the laminated glass intermediate film are different after tape casting is adopted is solved.

Description

Technical Field

[0001] The present invention relates to the field of interlayer films for laminated glass, and specifically relates to a polyvinyl butyral resin, an interlayer film for laminated glass, and a laminated glass. Background Art

[0002] Laminated glass, through the composite structure of "glass + interlayer film + glass", performs excellently in terms of safety, sound insulation, impact resistance, etc., and is a preferred material in fields such as transportation and construction. The core feature of laminated glass is that even when broken, the fragments will be adhered by the interlayer film, avoiding the splashing of glass fragments and causing injury to people. At the same time, it has sound insulation, ultraviolet protection, and impact resistance properties. The excellent properties of the above-mentioned laminated glass rely on the interlayer film.

[0003] Due to the excellent properties such as adhesiveness, light transmittance, and flexibility of polyvinyl butyral (PVB), it is the most commonly used interlayer film in laminated glass. In the prior art, the processing methods of PVB interlayer films are mainly melt extrusion casting or solution casting. However, these two traditional casting methods will cause the PVB molecular chains to orient along the casting direction during the processing, resulting in differences in the properties of the processed PVB finished product in the casting direction (longitudinal direction) and the direction perpendicular to the casting direction (transverse direction). This difference in properties in different directions brings great inconvenience during use and even affects the final use effect of the product. The prior art reduces the longitudinal and transverse differences by adding tempering, heat treatment and other methods in the subsequent processes of casting to restore the oriented molecular chains. However, this method completely relies on the curling movement of the molecular chains themselves, and the effect is very limited.

[0004] In order to solve the above problems, currently, there is an urgent need to invent a polyvinyl butyral resin, an interlayer film for laminated glass, and a laminated glass to solve the influence of the differences in the transverse and longitudinal properties of the PVB interlayer film on the laminated glass. Summary of the Invention

[0005] In the first aspect of the present invention, a polyvinyl butyral resin is provided. The first purpose is to provide a raw material of polyvinyl butyral resin for interlayer films with small differences in transverse and longitudinal properties, so as to reduce or avoid the influence on the interlayer film caused by the differences in the transverse and longitudinal properties of the raw material.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions.

[0007] A polyvinyl butyral resin, wherein the polyvinyl butyral resin is condensed from n-butyraldehyde, a cyclic polyaldehyde compound and polyvinyl alcohol under acid catalysis conditions; the cyclic polyaldehyde compound includes at least two aldehyde groups; by weight: the polyvinyl alcohol is 100 parts, the n-butyraldehyde is 45 parts to 60 parts, and the cyclic polyaldehyde compound is 0.09 parts - 0.029 parts.

[0008] A polyvinyl butyral resin provided by the present invention, wherein the cyclic polyaldehyde compound comprises one or a mixture of two of an aromatic polyaldehyde compound and a heterocyclic polyaldehyde compound.

[0009] A polyvinyl butyral resin provided by the present invention, wherein the n-butyraldehyde and the cyclic polyaldehyde compound are separately added into the container containing the polyvinyl alcohol in multiple times.

[0010] A polyvinyl butyral resin provided by the present invention, wherein the cyclic polyaldehyde compound and the polyvinyl alcohol satisfy the following conditions: 0.0005 ≤ Σ (number of aldehyde groups of polyaldehyde compound × moles of polyaldehyde compound) / (moles of polyvinyl alcohol structural units) ≤ 0.0016. The cyclic polyaldehyde may include an alicyclic polyaldehyde, an aromatic polyaldehyde, a heterocyclic polyaldehyde, etc., and the polyaldehyde may include a dialdehyde, a trialdehyde, a tetraaldehyde, etc., that is, the cyclic polyaldehyde includes an alicyclic dialdehyde, an alicyclic trialdehyde, an alicyclic tetraaldehyde, an aromatic dialdehyde, an aromatic trialdehyde, an aromatic tetraaldehyde, a heterocyclic dialdehyde, a heterocyclic trialdehyde, a heterocyclic tetraaldehyde, etc. The following listed cyclic polyaldehyde compounds are exemplary and are only used to explain the present invention and should not be construed as a limitation to the present invention;

[0011]

[0012] A polyvinyl butyral resin provided by the present invention, wherein the average degree of polymerization of the polyvinyl alcohol ranges from 1000 to 3000, and the degree of alcoholysis of the polyvinyl alcohol ranges from 88% to 100%.

[0013] In the second aspect of the present invention, there is provided an interlayer film for laminated glass. The second object is to provide an interlayer film with less difference in transverse performance and longitudinal performance, so that the performance of the interlayer film tends to be equal in all directions, and to avoid the influence on the laminated glass caused by the weak point in the performance of the interlayer film in a certain direction.

[0014] To achieve the second object, the present invention adopts the following technical solutions.

[0015] An interlayer film for laminated glass, comprising the polyvinyl butyral resin provided by the present invention and a plasticizer.

[0016] An interlayer film for laminated glass provided by the present invention, by weight, the interlayer film comprises 100 parts of polyvinyl butyral resin and 10 parts - 40 parts of plasticizer.

[0017] A middle film for laminated glass provided by the present invention, the middle film is a single-layer film or a multi-layer film; the multi-layer film refers to a composite film of two or more layers, and at least one layer of the multi-layer film includes the polyvinyl butyral resin in the present invention; preferably, all layers of the multi-layer film include the polyvinyl butyral resin in the present invention. When the middle film is a multi-layer film, the orientations between the layers of the middle film are the same or different.

[0018] For the middle film of laminated glass provided by the present invention, the transverse tensile strength and longitudinal tensile strength of the polyvinyl acetal resin satisfy: ΔR = |longitudinal tensile strength - transverse tensile strength| / max(longitudinal tensile strength, transverse tensile strength) ≤ 0.1; And / or, the longitudinal elongation at break and transverse elongation at break of the polyvinyl acetal resin satisfy: Δe = |longitudinal elongation at break - transverse elongation at break| / max(longitudinal elongation at break, transverse elongation at break) ≤ 0.1.

[0019] In the third aspect of the present invention, a laminated glass is provided. The third object is to provide a middle film with a small difference in transverse performance and longitudinal performance, so that the performance of the middle film in all directions tends to be equal, and to avoid the influence on the laminated glass caused by the weak point in the performance of the middle film in a certain direction.

[0020] To achieve the third object, the present invention adopts the following technical solutions.

[0021] A laminated glass includes the middle film provided by the present invention, and glasses adhered to opposite sides of the middle film in the thickness direction.

[0022] A laminated glass provided by the present invention, the laminated glass is a building laminated glass or an automotive laminated glass.

[0023] Compared with the prior art, the present invention has the following technical effects: A polyvinyl butyral resin, a middle film for laminated glass and a laminated glass provided by the present invention can significantly reduce the problem of the difference in transverse performance and longitudinal performance of the polyvinyl butyral resin caused by the molecular chain orientation by adding a small amount of cyclic polyaldehyde compound in the process of synthesizing polyvinyl butyral (PVB) resin, thereby solving the problem of the difference in transverse performance and longitudinal performance of the middle film for laminated glass after casting molding.

[0024] By describing the exemplary embodiments of the present invention in detail with reference to the following drawings, other features and advantages of the present invention will become clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0026] Figure 1 Shows the longitudinal tensile curve of the interlayer film of laminated glass in the first embodiment of the present invention.

[0027] Figure 2 Shows the transverse tensile curve of the interlayer film of laminated glass in the first embodiment of the present invention. Detailed implementation manners

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. The description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0029] For technologies, methods, and devices known to those of ordinary skill in the relevant fields, detailed discussions may not be made, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorization specification.

[0030] In the description of the present invention, it should be understood that using terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Without additional statements, the above terms have no special meanings and therefore should not be construed as limiting the protection scope of the present invention.

[0031] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] Polyvinyl butyral resin is an important raw material for manufacturing the interlayer film of laminated glass. It is synthesized by the condensation of polyvinyl alcohol (PVA) and n-butyraldehyde under acidic catalytic conditions. The higher the performance of polyvinyl butyral resin, the better the performance of the interlayer film of laminated glass, which is beneficial to both the manufacturing and use performance of laminated glass.

[0033] In the related art, generally, heat treatment processes such as tempering are added in the subsequent processes of the casting and forming of the interlayer film of laminated glass to reduce the differences in the transverse and longitudinal properties of the interlayer film of laminated glass.

[0034] However, methods such as heat treatment in the prior art rely entirely on the curling motion of molecular chains, and the effect is very limited. In the process of practicing the present invention, the inventors found that adding a small amount of cyclic polyaldehyde during the synthesis of polyvinyl butyral has a significant impact on improving the transverse and longitudinal properties of the interlayer film of laminated glass.

[0035] Based on the above findings, the present invention improves polyvinyl butyral resin to improve the various properties of the interlayer film of laminated glass and laminated glass.

[0036] A polyvinyl butyral resin, wherein the polyvinyl butyral resin is condensed from n-butyraldehyde, a cyclic polyaldehyde compound and polyvinyl alcohol under acid catalysis; the cyclic polyaldehyde compound includes at least two aldehyde groups; by weight: the polyvinyl alcohol is 100 parts, the n-butyraldehyde is 45 parts to 60 parts, and the cyclic polyaldehyde compound is 0.09 part to 0.29 part.

[0037] Specifically, relative to 100 parts by weight of polyvinyl alcohol, the n-butyraldehyde is 45 parts, 46 parts, 47 parts, 48 parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts and 60 parts, and the cyclic polyaldehyde compound is 0.09 part, 0.1 part, 0.12 part, 0.15 part, 0.2 part, 0.22 part, 0.25 part, 0.29 part. There is no special requirement for the addition ratio between the n-butyraldehyde and the cyclic polyaldehyde, and the above weight fractions are sufficient. There is no specific requirement for the above polyvinyl alcohol. Exemplary polyvinyl alcohol can be 1799 polyvinyl alcohol produced by Anhui Wanwei High-Tech Materials Co., Ltd. Preferably, the average degree of polymerization of the polyvinyl alcohol is 1000-3000. For example, the average degree of polymerization of the polyvinyl alcohol is 1000, 1200, 1500, 1800, 2000, 2500, 2800, 3000, etc.; the cyclic polyaldehyde only needs to have a cyclic structure and two or more aldehyde functional groups. The acid catalysis conditions can include inorganic acids such as hydrochloric acid, phosphoric acid, sulfuric acid, etc., and organic acids such as benzenesulfonic acid, oxalic acid, etc.

[0038] In a specific embodiment, the cyclic polyaldehyde compound includes one or a mixture of two of an aromatic polyaldehyde compound and a heterocyclic polyaldehyde compound. Exemplarily, the aromatic polyaldehyde can be selected from 2,5-dimethylterephthalaldehyde, 2,5-dihydroxyterephthalaldehyde, 2,5-dimethoxybenzene-1,4-dialdehyde, etc., and the heterocyclic polyaldehyde can be selected from 2,5-dialdehydepyridine, pyridine-2,6-dialdehyde, 2,5-dialdehydepyrazine, etc.

[0039]

[0040] In a specific embodiment, the n-butyraldehyde and the cyclic polyaldehyde compound are respectively added into the container containing the polyvinyl alcohol in multiple times. Specifically, the n-butyraldehyde and the cyclic polyaldehyde are added into the reaction at least twice. It can be understood that the addition order of the n-butyraldehyde and the cyclic polyaldehyde is: n-butyraldehyde - cyclic polyaldehyde - n-butyraldehyde - cyclic polyaldehyde - n-butyraldehyde - cyclic polyaldehyde are repeatedly and alternately added into the reaction. The addition amount each time can be added according to the average value of the total addition amount or according to a certain ratio. Exemplarily, the reaction can be carried out by adding 50% n-butyraldehyde - 50% cyclic polyaldehyde - 50% n-butyraldehyde - 50% cyclic polyaldehyde. It can be understood that, taking 50 parts of n-butyraldehyde as an example, 50% n-butyraldehyde means 25 parts of n-butyraldehyde; or the reaction can also be carried out by adding 70% n-butyraldehyde - 70% cyclic polyaldehyde - 30% n-butyraldehyde - 30% cyclic polyaldehyde.

[0041] In a specific embodiment, the cyclic polyaldehyde compound and the polyvinyl alcohol satisfy the following conditions: 0.0005 ≤ Σ(mole number of aldehyde groups of polyaldehyde compound × mole number of polyaldehyde compound) / (mole number of structural units of polyvinyl alcohol) ≤ 0.0016. Specifically, Σ(mole number of aldehyde groups of polyaldehyde compound × mole number of polyaldehyde compound) represents the total mole number of aldehyde groups in the polyaldehyde compound. If one polyaldehyde is added, it is the mole number of aldehyde groups of this single polyaldehyde. If multiple polyaldehydes are added, it is the sum of the mole numbers of aldehyde groups of each polyaldehyde; the mole number of structural units of polyvinyl alcohol represents the mole number of -CH2-CHOH- structural units in the added PVA. For the convenience of description, it is defined that: mole number ratio M = Σ(mole number of aldehyde groups of polyaldehyde compound × mole number of polyaldehyde compound) / (mole number of structural units of polyvinyl alcohol).

[0042] In a specific embodiment, the polyvinyl acetal resin is made into a film or sheet by melt extrusion casting or solution casting, and its transverse tensile strength, longitudinal tensile strength, transverse elongation at break and longitudinal elongation at break are measured. The transverse tensile strength and longitudinal tensile strength of the polyvinyl acetal resin satisfy: ΔR = |longitudinal tensile strength - transverse tensile strength| / max(longitudinal tensile strength, transverse tensile strength) ≤ 0.1; And / or, the longitudinal elongation at break and transverse elongation at break of the polyvinyl acetal resin satisfy: Δe = |longitudinal elongation at break - transverse elongation at break| / max(longitudinal elongation at break, transverse elongation at break) ≤ 0.1.

[0043] Preferably, ΔR = |longitudinal tensile strength - transverse tensile strength| / max(longitudinal tensile strength, transverse tensile strength) ≤ 0.05, and Δe = |longitudinal elongation at break - transverse elongation at break| / max(longitudinal elongation at break, transverse elongation at break) ≤ 0.05.

[0044] Specifically, it should be noted that the longitudinal direction refers to the MD direction, which is the flow direction of the film during the manufacture of the film material; the transverse direction refers to the TD direction, which is the direction orthogonal to the flow direction of the film during the manufacture of the film material and is also orthogonal to the thickness direction of the film. The transverse tensile strength, longitudinal tensile strength, transverse elongation at break, and longitudinal elongation at break of the polyvinyl acetal resin in this embodiment refer to the film formed by directly melt-extrusion casting or solution casting of the polyvinyl acetal resin (solution casting is to dissolve the polyvinyl acetal resin in a solvent to form a solution), and the composition of this film is only the polyvinyl butyral resin in the present invention. The longitudinal tensile strength is the strength measured by applying a tensile force along the MD direction, the transverse tensile strength is the strength measured by applying a tensile force along the TD direction, the longitudinal elongation at break corresponds to the longitudinal tensile strength, and the transverse elongation at break corresponds to the transverse tensile strength. |longitudinal tensile strength - transverse tensile strength| and |longitudinal elongation at break - transverse elongation at break| represent absolute values, and max(longitudinal tensile strength, transverse tensile strength) and max(longitudinal elongation at break, transverse elongation at break) represent the maximum value of the two.

[0045] An interlayer film for laminated glass comprises the polyvinyl butyral resin and plasticizer provided by the present invention. Specifically, for the interlayer film for laminated glass, relative to 100 parts by weight of the polyvinyl butyral resin, the plasticizer is 10 to 40 parts, and exemplary plasticizers are 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts and 40 parts, etc. Preferably, the plasticizer is 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts. There is no particular requirement for the type of plasticizer, and conventionally known plasticizers can be used. Exemplarily, the plasticizer can be a mixture of one or more of the following: triethylene glycol bis(2-ethylpropionate), triethylene glycol bis(2-ethylbutyrate), triethylene glycol bis(2-ethylhexanoate) (3G0), triethylene glycol dioctoate, triethylene glycol bis(n-octoate), triethylene glycol bis(n-heptanoate), tetraethylene glycol bis(n-heptanoate), dibutyl sebacate, dioctyl azelate, dibutyl carbitol adipate, ethylene glycol bis(2-ethylbutyrate), 1,3-propanediol bis(2-ethylbutyrate), 1,4-butanediol bis(2-ethylbutyrate), diethylene glycol bis(2-ethylbutyrate), diethylene glycol bis(2-ethylhexanoate), dipropylene glycol bis(2-ethylbutyrate), triethylene glycol bis(2-ethylvalerate), tetraethylene glycol bis(2-ethylbutyrate), diethylene glycol dioctoate, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, dihexyl adipate, dioctyl adipate, hexylcyclohexyl adipate, a mixture of heptyl adipate and nonyl adipate, diisononyl adipate, diisodecyl adipate, heptylnonyl adipate, dibutyl sebacate, oil-modified sebacic alkyd, and a mixture of phosphate ester and adipate ester, etc.

[0046] There is no special requirement for the preparation of the interlayer film for laminated glass, and conventionally known preparation techniques can be used.

[0047] In a specific embodiment, the interlayer film is a single-layer film or a multi-layer film; when the interlayer film is a multi-layer film, the orientations between layers of the interlayer film are different. Among them, the different orientations between layers mean that the MD direction of the first layer is consistent with the TD direction of the second layer, as Figure 1 shown. The multi-layer film is prepared by a lamination technique for the interlayer film.

[0048] A laminated glass comprises the interlayer film provided by the present invention, and glasses adhered to opposite sides of the interlayer film along the thickness direction.

[0049] Synthesis of polyvinyl butyral resin Dissolve 100 parts of PVA1799 and 0.1 - 0.5 parts of antioxidant in water to prepare a PVA aqueous solution with a concentration of 8 - 11%. Cool it to 16 - 20°C, and add successively: 30 parts of butyraldehyde - 0.1 part of 2,5 - dimethyl terephthalaldehyde - 30 parts of butyraldehyde - 0.1 part of 2,5 - dimethyl terephthalaldehyde. The interval between each addition is not less than 20 minutes. After all additions are completed, cool it to 10 - 15°C and add 10 - 30 parts of concentrated hydrochloric acid. After 1 hour, heat it up to 60 - 70°C at a heating rate of 0.2 - 0.7°C / min and keep it warm for 1 - 3 hours. Through processes such as washing, neutralizing, centrifuging, and drying, the target polyvinyl butyral resin is obtained.

[0050] Preparation of polyvinyl butyral resin film Cast the above polyvinyl butyral resin into a film through an extruder. The extrusion temperature is 180°C - 220°C. After the polyvinyl butyral resin is extruded from the die head, it is cooled by air cooling or water cooling to obtain the polyvinyl butyral resin film.

[0051] Heat treatment step: Temper in a constant temperature and humidity environment 5 - 20°C higher than the glass transition temperature of the polyvinyl butyral resin film for 30 minutes and then wind up. (In the example steps of the present invention, the heat treatment step is omitted, while in the comparative example, the heat treatment step is added).

[0052] Preparation of intermediate film Mix 100 parts of the above polyvinyl butyral resin with 0.1 - 0.5 parts of main antioxidant and 0.1 - 0.5 parts of auxiliary antioxidant using a high - speed mixer. If necessary, other functional additives such as ultraviolet absorbers, light stabilizers, heat - insulating additives, and flame - retardant additives can also be added. Cast the fully mixed solid raw materials and 10 - 40 parts of plasticizer into a film through an extruder. The extrusion temperature is 160 - 200°C. After the film is extruded from the die head, it is cooled by air cooling or water cooling to obtain the film.

[0053] Heat treatment step: Temper in a constant temperature and humidity environment 5 - 20°C higher than the glass transition temperature of the film for 30 minutes and then wind up. (In the example steps of the present invention, the heat treatment step is omitted, while in the comparative example, the heat treatment step is added) Using the above preparation process of the intermediate film, a single - layer intermediate film can be prepared, or different single - layer films prepared by the above method can be laminated and compounded into a multi - layer intermediate film, or a multi - layer intermediate film can be directly made by a multi - layer co - extrusion method.

[0054] The cross - section of the single - layer intermediate film or multi - layer intermediate film made by the above method can be rectangular or wedge - shaped.

[0055] The surface of the above intermediate film can be embossed to form a rough surface.

[0056] This process is used for the preparation of the interlayer film and the polyvinyl butyral resin film. The thickness of the film is prepared according to the actual situation. For example, the thickness of the film is 0.01 mm - 1.6 mm. Exemplarily, the thickness of the film is 0.38 mm, 0.76 mm, 0.81 mm, 1.14 mm, 1.52 mm, etc. The thickness of the interlayer film or the polyvinyl butyral resin film in the present invention is 0.76 mm or 0.81 mm.

[0057] Preparation of laminated glass The laminated glass has a three-layer structure of a first layer of glass, an interlayer film, and a second layer of glass. The interlayer film is the interlayer film made of the PVB resin of the present invention.

[0058] The above-mentioned first layer of glass and the second layer of glass can be inorganic glass, organic glass, or a combination of inorganic glass and organic glass. Inorganic glass includes but is not limited to float glass, tempered glass, frosted glass, sandblasted glass, embossed glass, wired glass, coated glass, etc.; organic glass includes but is not limited to PET sheets, PMMA sheets, PC sheets, PA sheets, etc.

[0059] The first layer of glass, the interlayer film, and the second layer of glass have the same size (length and width). The thickness of the first layer of glass and the second layer of glass is 2 mm - 3 mm. Exemplarily, the specifications of the first layer of glass and the second layer of glass are 50 mm × 50 mm × 2.5 mm, and the size of the interlayer film is 50 mm × 50 mm × 0.81 mm. Due to possible errors in the cutting of the sizes of the first layer of glass, the second layer of glass, and the interlayer film, when preparing the laminated glass, two adjacent sides need to be aligned, and the situation of these two sides shall be taken as the standard when observing the overflow of glue, etc.

[0060] There is no particular limitation on the preparation method of the laminated glass. For example, stack them in the order of the first layer of glass / interlayer film / second layer of glass, and then roll press them, or put them into a rubber bag for vacuum degassing. Subsequently, pre-bonding is carried out at 70 - 110 °C, and after pre-bonding, it is put into an autoclave for heating and pressurization to obtain the laminated glass.

[0061] Evaluation method.

[0062] 1. Tensile strength, elongation at break, tensile elastic modulus The tensile strength, elongation at break, and tensile elastic modulus are tested with reference to GB / T 1040.3 "Plastics - Determination of tensile properties - Part 3: Test conditions for films and sheets".

[0063] 2. Thermal shrinkage rate The thermal shrinkage rate is tested with reference to GB / T 12027 "Plastics - Films and sheets - Test method for dimensional change in heating".

[0064] 3. Plasticizer spillage Cut two PET sheets (with a thickness of 0.5 mm - 1.5 mm) according to 10 cm × 10 cm, cut out the interlayer glass interlayer film of the present application with a size of 5 cm × 5 cm, and sandwich the interlayer glass interlayer film between the two PET sheets to form a laminate. Place the laminate in a laminator, evacuate it at a certain temperature and maintain a certain pressure. The working parameters of the laminator are: temperature 80 °C, pressure 1.2 MPa, vacuum degree 0.08 MPa, and time 15 min. After taking it out, take out the interlayer glass interlayer film from the laminate and observe whether the plasticizer migrates out of the interlayer film.

[0065] 4. Condition of bubbles in laminated glass Manually observe the condition of bubbles.

[0066] 5. Condition of glue overflow in laminated glass First, manually observe the condition of glue overflow in the laminated glass; then use an optical microscope with size measurement (exemplarily, the optical microscope model is TMR4000, Beijing Times Peak Technology Co., Ltd.) to observe the condition of glue overflow in the laminated glass and measure the size of the glue overflow.

[0067] Table 1

[0068] Continued Table 1

[0069] Table 2

[0070] Continued Table 2

[0071] Table 3

[0072] Continued Table 3

[0073] The above are only exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A polyvinyl butyral resin, characterized in that, The polyvinyl butyral resin is formed by the condensation of n-butyraldehyde, cyclic polyaldehyde compound and polyvinyl alcohol under the condition of acid catalysis; the cyclic polyaldehyde compound includes at least two aldehyde groups; by weight: 100 parts of the polyvinyl alcohol, 45 parts - 60 parts of the n-butyraldehyde, and 0.09 parts - 0.29 parts of the cyclic polyaldehyde compound.

2. The polyvinyl butyral resin according to claim 1, wherein The cyclic polyaldehyde compound includes one or a mixture of two of aromatic polyaldehyde compounds and heterocyclic polyaldehyde compounds.

3. A polyvinyl butyral resin according to claim 1, wherein, The n-butyraldehyde and the cyclic polyaldehyde compound are respectively added into the container containing the polyvinyl alcohol in multiple times.

4. A polyvinyl butyral resin according to claim 1, characterized in that, The cyclic polyaldehyde compound and the polyvinyl alcohol satisfy the following conditions: 0.0005 ≤ Σ (number of aldehyde groups of polyaldehyde compound × number of moles of polyaldehyde compound) / (number of moles of polyvinyl alcohol structural unit) ≤ 0.0016.

5. An interlayer film for laminated glass, characterized in that, It includes the polyvinyl butyral resin according to any one of claims 1 - 5 and a plasticizer.

6. The interlayer film for laminated glass according to claim 5, characterized in that, By weight, the interlayer film includes 100 parts of the polyvinyl butyral resin and 10 parts - 40 parts of the plasticizer.

7. The interlayer film for laminated glass according to claim 5, characterized in that, The transverse tensile strength and longitudinal tensile strength of the polyvinyl acetal resin satisfy: ΔR = ︱longitudinal tensile strength - transverse tensile strength︱ / max (longitudinal tensile strength, transverse tensile strength) ≤ 0.1; And / or, the longitudinal elongation at break and transverse elongation at break of the polyvinyl acetal resin satisfy: Δe = ︱longitudinal elongation at break - transverse elongation at break︱ / max (longitudinal elongation at break, transverse elongation at break) ≤ 0.

1.

8. A middle film for laminated glass according to claim 5, characterized in that, The interlayer film is a single-layer film or a multi-layer film.

9. A laminated glass, characterized in that, It includes the interlayer film according to any one of claims 5 - 8, and glasses adhered to opposite sides of the interlayer film along the thickness direction.

10. A laminated glass according to claim 9, characterized in that, The laminated glass is architectural laminated glass or automotive laminated glass.

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