Drip-proof flame-retardant film and method for manufacturing the same

Abstract

The application discloses a kind of drip-proof flame-retardant films and its manufacturing method, belong to plastic film field.The drip-proof flame-retardant film includes: composite flame-retardant polyester film base film, at least one surface of the base film is equipped with thermal adhesive layer;The thermal adhesive layer is made of low-melting-point polyester material, the melting point of the low-melting-point polyester material is lower than 150 DEG C;The base film contains flame-retardant component;In the surface of the thermal adhesive layer, there is incombustible fiber layer.The flow ability of molten polyester film is limited under the physical hindering effect of incombustible fiber layer, and the occurrence of dripping phenomenon is effectively prevented.Experimental data show that when fiber length is greater than or equal to 8mm and the amount of addition is greater than or equal to 10 cm / cm 2 , no dripping can be achieved.The phosphorus flame retardant compounded in the base film can effectively inhibit combustion, and the physical barrier effect of the incombustible fiber layer can make the film reach a high flame-retardant grade.

Description

Technical Field

[0001] This invention relates to plastic films, and more particularly to an anti-drip flame-retardant film and its manufacturing method. Background Technology

[0002] Polyester film, as an important functional plastic film, is widely used in electronics, building decoration, packaging materials, and other fields. With the continuous improvement of application demands, higher requirements are being placed on the flame-retardant properties of polyester film.

[0003] However, existing flame-retardant polyester films have a significant problem when exposed to open flames or high temperatures: the film softens and melts, causing it to drip. This dripping not only leads to the spread of flames but may also ignite flammable materials below, causing the fire to expand and creating a serious safety hazard. Particularly in applications such as building decoration materials and electronic products, the dripping problem of flame-retardant films severely limits their actual protective effect.

[0004] Currently, while some technologies improve the flame retardant properties of polyester films by adding flame retardants, these methods mainly focus on increasing the film's flame retardant rating, with limited effectiveness in suppressing melt dripping. Therefore, there is an urgent need to develop a flame-retardant film that can effectively prevent melt dripping while maintaining good flame retardant properties. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide an anti-drip flame-retardant film and its manufacturing method, which aims to solve the problem that existing flame-retardant polyester films are prone to melting and dripping when heated or burning, leading to the spread of flames and the expansion of fire, posing a safety hazard.

[0006] Technical solution: The first aspect of the present invention provides an anti-drip flame-retardant film, comprising:

[0007] A composite flame-retardant polyester film base film, wherein at least one surface of the base film is provided with a thermal adhesive layer;

[0008] The thermal adhesive layer is made of a low-melting-point polyester material, the melting point of which is below 150°C;

[0009] The base film contains flame-retardant components;

[0010] A non-flammable fiber layer is bonded to the surface of the thermal adhesive layer.

[0011] Furthermore, the low-melting-point polyester material is preferably one or both of CHDM-modified PETG or IPA-modified APET, with a melting point of approximately 120°C.

[0012] Furthermore, the flame-retardant component is preferably a phosphorus-based flame retardant.

[0013] Furthermore, the non-flammable fiber is preferably one or more of glass fiber, quartz fiber, or silicon carbide fiber.

[0014] Furthermore, the morphology of the non-flammable fiber can be selected from one or more of straight fibers, curved fibers, side-branched fibers, or mesh-structured fibers.

[0015] Furthermore, the length of the non-flammable fiber is preferably greater than or equal to 3 mm, and the diameter is 0.1 to 10 μm.

[0016] Furthermore, the amount of non-flammable fiber added to the surface of the thermally bonded layer is preferably 1 to 100 cm / cm². 2 .

[0017] Furthermore, the non-flammable fibers can be pretreated with a coupling agent to enhance their adhesion to the thermal adhesive layer.

[0018] Furthermore, the non-flammable fiber layer may be disposed on one or both sides of the base film.

[0019] A second aspect of the present invention provides a method for preparing an anti-drip flame-retardant film, comprising the following steps:

[0020] S1. Raw material preparation: Mix polyester chips with flame retardant masterbatch to obtain flame retardant polyester mixture;

[0021] S2. Drying treatment: The flame-retardant polyester mixture is dried.

[0022] S3. Melt extrusion: The dried flame-retardant polyester mixture is heated to a molten state and extruded into a film; wherein, the low-melting-point polyester material is simultaneously extruded through another extruder to form a thermally bonded layer;

[0023] S4. Cooling and film formation: Cooling and shaping the extruded molten film to obtain a composite flame-retardant polyester film base film;

[0024] S5. Fiber hot-press bonding: The composite flame-retardant polyester film base film is heated to a temperature above the melting point of the low-melting-point polyester material, and non-flammable fibers are pressed into the hot-press layer by hot pressing. Then, it is rapidly cooled to make the non-flammable fibers firmly bonded to the surface of the hot-press layer.

[0025] Further, in step S1, the preferred mass ratio of the polyester chips to the flame-retardant masterbatch is 85:15.

[0026] Furthermore, in step S3, the temperature of melt extrusion is preferably 270°C to 290°C.

[0027] Furthermore, the preparation method also includes step S6: longitudinal stretching treatment, with a stretching temperature of 80°C to 125°C and a stretching ratio of 2.6 to 3.8.

[0028] Furthermore, step S6 is followed by step S7: transverse stretching treatment, with a stretching temperature of 100°C to 150°C and a stretching ratio of 3.0 to 4.0.

[0029] Further, in step S1, the polyester chips may be selected from one or a mixture of two of conventional polyester chips or copolyester chips.

[0030] Furthermore, in step S3, 800 to 2000 ppm of silica slip agent may be added to the thermal adhesive layer.

[0031] Beneficial effects:

[0032] (1) By physically hindering the flow of the molten polyester film through the non-flammable fiber layer, dripping is effectively prevented. Experimental data show that when the fiber length is ≥8mm and the addition amount is ≥10 cm / cm, the flow rate of the molten polyester film is limited. 2 At this time, it can achieve a completely drip-free process.

[0033] (2) The phosphorus-based flame retardant in the base film can effectively suppress combustion, and together with the physical barrier effect of the non-combustible fiber layer, the film can achieve a high flame retardant rating.

[0034] (3) The melting point of the thermal adhesive layer is designed to be about 120°C, which has good matching with the processing temperature of conventional polyester film, making it easy to modify existing equipment and produce.

[0035] (4) The type, form, amount of non-flammable fiber and single / double side settings can be adjusted according to actual needs to flexibly meet the needs of different application scenarios.

[0036] (5) The low melting point thermal adhesive layer softens and melts under heating conditions, which can firmly wrap the non-flammable fiber. After rapid cooling, it forms a stable mechanical interlocking structure, and the fiber is not easy to fall off. Detailed Implementation

[0037] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments.

[0038] Example 1: Preparation of anti-drip flame-retardant film

[0039] This embodiment provides a method for preparing an anti-drip flame-retardant film, including the following steps:

[0040] (1) Raw material preparation:

[0041] Main base film raw materials: conventional polyester chips and phosphorus-based flame retardant masterbatch HY-F4830 are mixed at a mass ratio of 85:15;

[0042] Thermal adhesive layer material: CHDM modified PETG low melting point polyester chips, melting point approximately 120℃;

[0043] (2) Drying treatment: Place the above raw materials in a drying equipment and dry them at 150°C for 6 hours to reduce the moisture content to below 30 ppm;

[0044] (3) Melt extrusion:

[0045] Two extruders are configured. The main extruder is used to extrude flame-retardant polyester blends, and the extrusion temperature is set to 280℃.

[0046] The auxiliary extruder is used to extrude low-melting-point polyester thermal adhesive layer material, and the extrusion temperature is set to 180℃;

[0047] The flame-retardant polyester layer and the thermal adhesive layer are composited by multi-layer co-extrusion mold, with the total film thickness controlled at 100μm and the thermal adhesive layer thickness at approximately 10μm.

[0048] (4) Cooling and film formation: The melt-extruded film is rapidly cooled and shaped by a cooling roller, with the temperature of the cooling roller set at 40°C;

[0049] (5) Fiber thermoforming:

[0050] The composite film base film is heated to 130°C using a heating device to soften and melt the thermal adhesive layer;

[0051] Glass fibers (2μm in diameter and 8mm in length) are evenly laid on the surface of the thermal adhesive layer using a fiber layup device, with an addition amount of 15 cm / cm². 2 ;

[0052] Hot roller pressing is used to press the glass fiber into the molten thermal adhesive layer, with the pressure set at 0.5 MPa;

[0053] Immediately after pressing, the film is rapidly cooled by cooling rollers to solidify the thermal adhesive layer and firmly bond the glass fiber to the film surface.

[0054] (6) Performance test: Vertical burning test (UL 94 V-0 standard), the test result is no dripping, flame retardant rating V-0.

[0055] The anti-drip flame-retardant film prepared in this embodiment has the following properties: the length of the glass fiber bonded to its surface is ≥8mm and the amount added is ≥10cm / cm. 2 It exhibits excellent anti-dripping performance in vertical burning tests.

[0056] Example 2: Preparation of Double-Sided Fiber-Reinforced Anti-Drip Flame-Retardant Film

[0057] This embodiment provides a method for preparing a double-sided fiber-reinforced anti-drip flame-retardant film, which differs from Embodiment 1 in that:

[0058] (1) The main base film raw material is a mixture of conventional polyester chips and copolyester chips (mass ratio 1:1), which is mixed with phosphorus flame retardant masterbatch HY-F4830 at a mass ratio of 85:15;

[0059] (2) The thermal adhesive layer material is IPA-modified APET low-melting-point polyester chips with a melting point of about 115°C;

[0060] (3) After melt extrusion, a composite film base film with thermal adhesive layers on both sides is obtained;

[0061] (4) Perform the same fiber thermo-press bonding treatment on the upper and lower surfaces of the film as in Example 1, so that the non-flammable glass fiber layer is bonded to both sides of the film.

[0062] (5) Glass fiber parameters: fiber diameter 2μm, length 10mm, double-sided addition amount 12 cm / cm 2 ;

[0063] (6) Performance test results: The double-sided fiber-reinforced structure makes the film constrained by the fiber layer on both sides when heated, and the anti-dripping effect is more significant. There was no dripping phenomenon in the vertical burning test.

[0064] Example 3

[0065] To verify the effect of different fiber morphologies on anti-drip performance, the following four groups of samples were prepared for comparative testing:

[0066]

[0067] Test conditions: Vertical combustion test, sample size 125±5mm in length and 13±0.5mm in width, flame height 20±1mm, ignition time 10±0.5s.

[0068] Test conclusion: When the fiber length is ≥8mm and the addition amount is ≥10 cm / cm 2 At the same time, it can achieve no dripping; curved fibers and fibers with side branches perform better under the same parameters due to their better mechanical locking effect.

[0069] Example 4

[0070] This embodiment verifies the effect of stretching treatment on the performance of the anti-drip flame-retardant film:

[0071] (1) After the film is extruded and cooled, it undergoes longitudinal stretching treatment:

[0072] Tensile temperature: 105℃;

[0073] Draw ratio: 3.2;

[0074] Film thickness after stretching: 50 μm;

[0075] (2) Perform transverse stretching after longitudinal stretching:

[0076] Tensile temperature: 125℃;

[0077] Draw ratio: 3.5;

[0078] Final film thickness: 25 μm;

[0079] (3) After stretching, the fibers are subjected to heat-press bonding treatment (same as in Example 1);

[0080] (4) Performance test results: The film after biaxial stretching has better dimensional stability and mechanical properties. While maintaining excellent anti-drip performance, the flatness and flexibility of the film are significantly improved.

[0081] Example 5

[0082] This embodiment verifies the effect of coupling agent pretreatment on the bond strength between fibers and thermal adhesive layers:

[0083] (1) Pre-treat the glass fiber with coupling agent before laying: soak it in silane coupling agent KH-550 treatment solution for 10 minutes, and then dry it in an oven at 120℃ for 30 minutes;

[0084] (2) Prepare an anti-drip flame-retardant film according to the process in Example 1;

[0085] (3) Adhesion strength test: The comparative example used glass fiber without coupling agent treatment;

[0086]

[0087] Test conclusion: Coupling agent pretreatment can significantly enhance the bonding strength between non-flammable fibers and thermal adhesive layers, and reduce the risk of fiber detachment during use.

[0088] Example 6

[0089] The anti-drip flame-retardant film of this invention was subjected to system performance testing according to the UL 94 V-0 test standard:

[0090] (1) Test sample information:

[0091] Number of samples: 21;

[0092] Spline dimensions: Length 125±5mm, Width 13±0.5mm

[0093] Film thickness: 100 μm;

[0094] Fiber parameters: Glass fiber, diameter 2μm, length 8mm, addition amount 15 cm / cm 2 ;

[0095] (2) Test conditions:

[0096] Pretreatment conditions 1: Temperature 23±2℃, relative humidity 50±10%, time 48h;

[0097] Pretreatment condition 2: Temperature 70±2℃, time 168±2h (aging treatment);

[0098] Flame height: 20±1mm;

[0099] Ignition time: 10±0.5s;

[0100] Number of ignition attempts: 2;

[0101] (3) Test results:

[0102]

[0103] Test conclusion: The anti-drip flame-retardant film of the present invention exhibits excellent anti-drip and flame-retardant properties under different pretreatment conditions, meeting the V-0 rating requirements.

[0104] Example 7

[0105] This embodiment establishes the relationship between fiber addition amount and anti-drip effect through systematic experimental data:

[0106]

[0107] Test conclusion:

[0108] When the fiber length is ≥8mm and the addition amount is ≥10 cm / cm², it can achieve complete drip-free operation;

[0109] Fiber length and addition amount must simultaneously meet critical conditions to effectively prevent dripping;

[0110] Due to its unique interwoven structure, mesh-structured fibers have a better anti-drip effect at the same addition amount.

[0111] Example 8

[0112] This embodiment compares the effects of different flame-retardant systems on the performance of the anti-drip flame-retardant film of the present invention:

[0113]

[0114] Test conclusion: Phosphorus-based flame retardants or phosphorus-nitrogen synergistic flame retardants have a good synergistic effect with the non-combustible fiber layer structure of the present invention, achieving excellent flame retardant performance without affecting the anti-dripping effect.

[0115] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A drip-proof flame-retardant film, characterized in that, include: A composite flame-retardant polyester film base film, wherein at least one surface of the base film is provided with a thermal adhesive layer; The thermal adhesive layer is made of a low-melting-point polyester material, the melting point of which is below 150°C; The base film contains flame-retardant components; A non-flammable fiber layer is bonded to the surface of the thermal adhesive layer.

2. The anti-drip flame-retardant film according to claim 1, characterized in that, The low-melting-point polyester material is selected from one or both of CHDM-modified PETG or IPA-modified APET.

3. The anti-drip flame-retardant film according to claim 1, characterized in that, The flame retardant component is a phosphorus-based flame retardant; the non-combustible fiber is selected from one or more of glass fiber, quartz fiber, silicon carbide fiber, silicon nitride fiber or aluminum-based fiber.

4. The anti-drip flame-retardant film according to claim 1, characterized in that, The non-flammable fiber is selected from one or more of the following forms: straight fiber, curved fiber, fiber with side branches, or mesh structure fiber; the non-flammable fiber has a length greater than or equal to 3 mm and a diameter of 0.1 to 10 μm.

5. The anti-drip flame-retardant film according to claim 1, characterized in that, The amount of non-flammable fiber added to the surface of the thermal adhesive layer is 1 to 100 cm / cm. 2 The non-flammable fiber layer is disposed on one or both sides of the base film.

6. A method for manufacturing an anti-drip flame-retardant film as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Raw material preparation: Mix polyester chips with flame retardant masterbatch to obtain flame retardant polyester mixture; S2. Drying treatment: The flame-retardant polyester mixture is dried, and the moisture content after drying is controlled to be less than 50 ppm; S3. Melt extrusion: The dried flame-retardant polyester mixture is heated to a molten state and extruded into a film; wherein, the low-melting-point polyester material is simultaneously extruded through another extruder to form a thermally bonded layer; S4. Cooling and film formation: Cooling and shaping the extruded molten film to obtain a composite flame-retardant polyester film base film; S5. Fiber hot-press bonding: The composite flame-retardant polyester film base film is heated to a temperature above the melting point of the low-melting-point polyester material, and non-flammable fibers are pressed into the hot-press layer by hot pressing. Then, it is rapidly cooled to make the non-flammable fibers firmly bonded to the surface of the hot-press layer.

7. The method for manufacturing the anti-drip flame-retardant film according to claim 6, characterized in that, In step S1, the mass ratio of the polyester chips to the flame retardant masterbatch is 85:15, and the flame retardant masterbatch is a phosphorus-based flame retardant masterbatch.

8. The method for manufacturing the anti-drip flame-retardant film according to claim 6, characterized in that, In step S3, the temperature of melt extrusion is 270°C to 290°C.

9. The method for manufacturing the anti-drip flame-retardant film according to claim 6, characterized in that, It also includes a stretching process: stretching the cooled base film longitudinally and / or stretching it transversely; the longitudinal stretching temperature is 80°C to 125°C and the stretching ratio is 2.6 to 3.8; the transverse stretching temperature is 100°C to 150°C and the stretching ratio is 3.0 to 4.

0.

10. The method for manufacturing the anti-drip flame-retardant film according to claim 6, characterized in that, The non-flammable fibers are pretreated with a coupling agent before hot-press bonding.

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