Agricultural flame-retardant weather-resistant polyester film and preparation method thereof

Abstract

The invention discloses an agricultural flame-retardant and weather-resistant polyester film and a preparation method thereof, the agricultural flame-retardant and weather-resistant polyester film adopts a phosphorus-based flame retardant with high phosphorus content, and the flame retardant property reaches the VTM-0 level under the UL94 combustion test standard. Besides, an ultraviolet absorbent, an antioxidant, an anti-hydrolysis agent and the like are also added into the polyester film, so that the flame retardant property is met, and the degradation phenomenon caused by ultraviolet irradiation and ester group hydrolysis is effectively solved. Meanwhile, the material proportion of the flame retardant, the ultraviolet absorbent, the antioxidant and the anti-hydrolysis agent is controlled, a protective network formed by the four auxiliaries through chemical reaction and physical action is utilized, the synergistic effect of the four auxiliaries is enhanced to the maximum extent, and the performance bottleneck of a single auxiliary is broken through. According to the agricultural flame-retardant weather-resistant polyester film prepared by the method, not only is the durability greatly improved, but also the stability and the safety of the agricultural flame-retardant weather-resistant polyester film under various environmental conditions are remarkably enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of polyester film, in particular to an agricultural flame-retardant weather-resistant polyester film and a preparation method thereof. BACKGROUND

[0002] With the development of agricultural modernization, the performance requirements for agricultural films are becoming higher and higher, and functional agricultural films have gradually begun to occupy the market. Agricultural polyester films are widely used in agricultural production due to their high strength, stretch resistance, puncture resistance, long service life, and low use cost. However, traditional agricultural polyester films have some shortcomings, such as poor flame retardant performance. In agricultural production, there are many fire hazards, such as open fire operations, electrical equipment failures, etc. Once a fire is triggered and spreads rapidly, it will not only cause damage to agricultural facilities, but also affect the growth of crops, and even cause casualties and huge property losses. In addition, long-term exposure to ultraviolet light and humid high-temperature environments can cause degradation reactions such as photooxidation and hydrolysis, leading to polymer chain breakage and accelerating material aging, which limits their application in high-temperature seasons and strong ultraviolet regions. SUMMARY

[0003] The present application solves the technical problem, provides an agricultural flame-retardant weather-resistant polyester film and a preparation method thereof, which is simple in process and has the characteristics of flame retardation, oxidation resistance, ultraviolet resistance, and hydrolysis resistance.

[0004] To solve the above problems, the technical scheme adopted by the present application is as follows: an agricultural flame-retardant weather-resistant polyester film, comprising the following components by mass fraction:

[0005]

[0006] The high-phosphorus-content phosphorus-based flame retardant is at least one of trihydroxypropyl phosphine oxide, cyclooctyl hydroxypropyl phosphine oxide, and p-di(2,2-cyanomethyl phosphine oxide) tetramethyl benzene.

[0007] The antioxidant is at least one of hydroquinone, thio-bisphenol, and phosphite ester.

[0008] The ultraviolet absorber is at least one of an o-nitroaniline and p-cresol reactant, 2-hydroxy-4-n-octyloxy benzophenone, and monobenzoic acid m-bisphenol ester.

[0009] The anti-hydrolysis agent is at least one of phenyl glycidyl ether, bisphenol A bis-glycidyl ether, and tetra(phenyl glycidyl ether) ethane.

[0010] The preparation method of the above-mentioned agricultural flame-retardant weather-resistant polyester film comprises the following steps:

[0011] (1) according to the proportion, the dried polyester chip, the silicon-containing polyester chip, the high-phosphorus-content phosphorus flame retardant, the antioxidant, the ultraviolet absorber and the hydrolysis inhibitor are mixed;

[0012] (2) the mixed raw materials are pre-crystallized at 140-160 DEG C for 30-60 minutes, and then dried at 160-180 DEG C for 4-6 hours; the raw materials are high-temperature melted and extruded through a single-screw extruder, the extrusion temperature is set to 260-275 DEG C, the extruded melt is quickly attached to a cold roller by means of a patch device, the melt is quickly cooled to form a cast piece, and the temperature of the cold roller is set to 25-30 DEG C;

[0013] (3) longitudinal stretching process: after the cast piece enters the longitudinal stretching machine, it passes through the preheating roller, the stretching roller, the cooling roller and the tension roller to complete the longitudinal stretching under the action of certain temperature and external force;

[0014] (4) transverse stretching process: the cast piece after the longitudinal stretching immediately enters the transverse stretching machine for stretching, and after the longitudinal stretching and the transverse stretching, the biaxially stretched polyester film with certain mechanical properties and stable heat shrinkage rate is formed;

[0015] (5) performance test: the flame retardant performance reaches the VTM-0 level of UL94 standard, and the ultraviolet transmittance is less than 4.

[0016] Further, in step (3), the longitudinal stretching temperature is set to 78-84 DEG C, and the stretching ratio is 2.8-3.4 times.

[0017] Further, in step (3), the transverse stretching preheating temperature is set to 95-100 DEG C, the transverse stretching temperature is set to 100-120 DEG C, the transverse stretching setting temperature is set to 175-240 DEG C, and the transverse stretching cooling temperature is set to 110-150 DEG C.

[0018] The application has the advantages and technical effects that the agricultural flame-retardant weather-resistant polyester film prepared by the above method uses the high-phosphorus-content phosphorus flame retardant, the ultraviolet transmittance is less than 4 while the flame retardant performance reaches the VTM-0 level of UL94 standard, the degradation phenomenon caused by ultraviolet radiation, oxidation and ester hydrolysis is effectively solved, the durability is greatly improved, and the stability and safety under various environmental conditions are significantly enhanced. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application; obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application, and all other embodiments obtained by those skilled in the art without creative labor on the basis of the embodiments in the application belong to the protection scope of the application.

[0020] The agricultural flame-retardant weather-resistant polyester film of the present application comprises the following components by mass fraction:

[0021]

[0022] The high-phosphorus-content phosphorus flame retardant is at least one of trihydroxypropyl phosphine oxide, cyclooctyl hydroxypropyl phosphine oxide, and p-di(2,2-cyanoethyl phosphine oxide methyl) tetramethyl benzene.

[0023] The antioxidant is at least one of hydroquinone, thio-bisphenol, and phosphite ester.

[0024] The ultraviolet absorber is at least one of an o-nitroaniline and p-cresol reactant, 2-hydroxy-4-n-octyloxy benzophenone, and m-benzene diol monobenzoate.

[0025] The hydrolysis-resistant agent is at least one of phenyl glycidyl ether, bisphenol A bisglycidyl ether, and tetra(phenyl glycidyl ether) ethane.

[0026] The agricultural flame-retardant weather-resistant polyester film of the present application and the preparation method thereof comprise the following steps:

[0027] (1) After drying the polyester chips, the silicon-containing polyester chips, the high-phosphorus-content phosphorus flame retardant, the antioxidant, the ultraviolet absorber, and the hydrolysis-resistant agent, mix them according to the corresponding proportions.

[0028] (2) Put the mixed raw materials into a crystallization tank, pre-crystallize them at 140-160°C for 30-60 minutes, prevent the raw material master batch from sticking to each other, then put them into a drying tank, dry them at 160-180°C for 4-6 hours to remove the water in the master batch. Melt and extrude the raw materials at high temperature through a single-screw extruder, set the extrusion temperature to 260-275°C, quickly attach the extruded melt to a cold roller through a patch device, quickly cool it to form a cast piece, and set the temperature of the cold roller to 25-30°C.

[0029] (3) Longitudinal stretching process: after the cast piece is peeled off from the cold roller and then enters the longitudinal stretching machine, it successively passes through a preheating roller, a stretching roller, a cooling roller, and a tension roller, and is longitudinally stretched under the action of a certain temperature and external force. Set the longitudinal stretching temperature to 78-84°C, and the stretching ratio to 2.8-3.4 times.

[0030] (4) Transverse stretching process: the cast sheet after longitudinal stretching is immediately pulled into the transverse stretching machine by the clamp for stretching, the transverse stretching preheating temperature is set to 95-100℃, the transverse stretching temperature is set to 100-120℃, the transverse stretching setting temperature is set to 175-240℃, and the transverse stretching cooling temperature is set to 110-150℃. After longitudinal stretching and transverse stretching, the biaxially stretched polyester film with certain mechanical properties and stable heat shrinkage rate is formed.

[0031] (5) Performance test: the flame retardant performance reaches VTM-0 level under UL94 standard, and the ultraviolet transmittance is less than 4.

[0032] The application controls the proportion of the materials of the flame retardant, the ultraviolet absorber, the antioxidant and the hydrolysis inhibitor, utilizes the synergistic effect of the ultraviolet absorber and the antioxidant to block the photo-oxidation aging cycle process; the ultraviolet absorber delays the PET molecular chain fracture through long-term light stabilization, and reduces the generation of low-molecular-weight combustible fragments during combustion; the phosphorus-containing active substances (such as PO·) generated by the decomposition of the phosphorus-based flame retardant can react with the free radicals (such as O2 - ·) generated by the ultraviolet excitation to inhibit the oxidation reaction in the initial combustion. The protective network formed by the chemical reaction and the physical effect of the four additives blocks the invasion of external energy (ultraviolet) and inhibits the generation of internal free radicals to achieve the effect of stabilizing the molecular chain structure and preventing the combustion reaction. At the same time, attention should be paid to the dosage proportion compatibility between the additives to prevent mutual antagonism between the additives. In this way, the synergistic effect between the four additives is maximized, and the performance bottleneck of a single additive is broken through.

[0033] Example 1: Preparation method of 23 mu agricultural flame-retardant weather-resistant polyester film

[0034] (1) After drying the polyester chip, the silicon-containing polyester chip, the high-phosphorus-content phosphorus-based flame retardant, the antioxidant, the ultraviolet absorber and the hydrolysis inhibitor, they are mixed according to the mass of 3872g, 1000g, 125g, 1g, 1g and 1g. The added high-phosphorus-content phosphorus-based flame retardant is a mixture of trihydroxypropyl phosphine oxide and p-di(2,2-cyanomethyl phosphine oxide) tetramethyl benzene with a mass ratio of 1:1. The added antioxidant is a mixture of hydroquinone and phosphite with a mass ratio of 1:1. The added ultraviolet absorber is a mixture of 2-hydroxy-4-n-octyloxy benzophenone and m-hydroquinone monobenzoate with a mass ratio of 1:1. The added hydrolysis inhibitor is a mixture of phenyl glycidyl ether and bisphenol A bisglycidyl ether with a mass ratio of 1:1.

[0035] (2) Put the mixed raw materials into a crystallization tank, and pre-crystallize at 140°C for 60 minutes while preventing the adhesion between the raw material master batches, and then put them into a drying tank, and dry them at 160°C for 4 hours to remove the water in the master batches. The raw materials are high-temperature melted and extruded through a single-screw extruder, the extrusion temperature is set to 260-275°C, the extruded melt is quickly attached to a cold roller by means of a patch device, and the cast sheet is quickly cooled to form a cast sheet, and the temperature of the cold roller is set to 30°C.

[0036] (3) Longitudinal stretching process: the cast sheet is peeled off from the cold roller and then enters the longitudinal stretching machine, and then passes through a preheating roller, a stretching roller, a cooling roller and a tension roller to complete the longitudinal stretching under the action of a certain temperature and external force. The longitudinal stretching temperature is set to 78-84°C, and the stretching ratio is 3.4 times.

[0037] (4) Transverse stretching process: the cast sheet after the longitudinal stretching is immediately pulled into the transverse stretching machine by a clamp for stretching, the transverse stretching preheating temperature is set to 95-100°C, the transverse stretching temperature is set to 100-120°C, the transverse stretching setting temperature is set to 175-240°C, and the transverse stretching cooling temperature is set to 110-150°C. After the longitudinal stretching and the transverse stretching, the biaxially stretched polyester film with certain mechanical properties and stable heat shrinkage rate is formed.

[0038] (5) Performance test: the flame-retardant performance reaches the VTM-0 level of the UL94 standard, and the ultraviolet transmittance is less than 4.

[0039] The agricultural flame-retardant weather-resistant polyester film prepared by the method has the following performance indexes (taking a 23 μm thick film as a reference):

[0040]

[0041] Example 2: Preparation method of 36 μm agricultural flame-retardant weather-resistant polyester film

[0042] (1) Dry the polyester chips, silicon-containing polyester chips, high-phosphorus-content phosphorus flame retardant, antioxidant, ultraviolet absorber and anti-hydrolysis agent, and then mix them according to the mass ratio of 3898.2 g, 1000 g, 100 g, 0.6 g, 0.6 g and 0.6 g. The added high-phosphorus-content phosphorus flame retardant is a mixture of trihydroxypropyl phosphine oxide and p-di(2,2-cyanoethyl phosphine oxide methyl) tetramethyl benzene with a mass ratio of 1:1. The added antioxidant is a mixture of hydroquinone and phosphite with a mass ratio of 1:1. The added ultraviolet absorber is a mixture of 2-hydroxy-4-n-octyloxy benzophenone and m-hydroquinone monobenzoate with a mass ratio of 1:1. The added anti-hydrolysis agent is a mixture of phenyl glycidyl ether and bisphenol A bisglycidyl ether with a mass ratio of 1:1.

[0043] (2) Put the mixed raw materials into a crystallization tank, and pre-crystallize at 150℃ for 45 minutes while preventing the raw material master batch from sticking together, and then put it into a drying tank, and dry it at 170℃ for 5 hours to remove the moisture in the master batch. The raw materials are high-temperature melted and extruded through a single-screw extruder, the extrusion temperature is set to 260-275℃, the extruded melt is quickly attached to the cold roller by the patch device, and the cold roller is quickly cooled to form a cast sheet, and the temperature of the cold roller is set to 28℃.

[0044] (3) Longitudinal stretching process: the cast sheet is peeled off from the cold roller and then enters the longitudinal stretching machine, and then passes through the preheating roller, stretching roller, cooling roller and tension roller to complete the longitudinal stretching under the action of certain temperature and external force. The longitudinal stretching temperature is set to 78-84℃, and the stretching ratio is 3.0 times.

[0045] (4) Transverse stretching process: the cast sheet after longitudinal stretching is immediately pulled into the transverse stretching machine by the clamp for stretching, the transverse stretching preheating temperature is set to 95-100℃, the transverse stretching temperature is set to 100-120℃, the transverse stretching setting temperature is set to 175-240℃, and the transverse stretching cooling temperature is set to 110-150℃. After longitudinal stretching and transverse stretching, a biaxially stretched polyester film with certain mechanical properties and stable heat shrinkage rate is formed.

[0046] (5) Performance test: the flame retardant performance reaches VTM-0 level of UL94 standard, and the ultraviolet transmittance is less than 4.

[0047] The agricultural flame-retardant weather-resistant polyester film prepared by the method of the application has the following performance indicators (taking a 36um thick film as a reference):

[0048]

[0049]

[0050] Example 3: Preparation method of 50μ agricultural flame-retardant weather-resistant polyester film

[0051] (1) The polyester chips, silicon-containing polyester chips, high phosphorus content phosphorus flame retardant, antioxidant, ultraviolet absorber, and hydrolysis inhibitor are dried, and then mixed in a mass ratio of 3949.25 g, 1000 g, 50 g, 0.25 g, 0.25 g, and 0.25 g. The added high phosphorus content phosphorus flame retardant is a mixture of trihydroxypropyl phosphine oxide and p-di(2,2-cyanoethyl phosphine oxide methyl) tetramethyl benzene in a mass ratio of 1:1. The added antioxidant is a mixture of hydroquinone and phosphite in a mass ratio of 1:1. The added ultraviolet absorber is a mixture of 2-hydroxy-4-n-octyloxy benzophenone and m-hydroquinone monobenzoate in a mass ratio of 1:1. The added hydrolysis inhibitor is a mixture of phenyl glycidyl ether and bisphenol A bisglycidyl ether in a mass ratio of 1:1.

[0052] (2) The mixed raw materials are placed in a crystallization tank, pre-crystallized at 160°C for 30 minutes, and then placed in a drying tank to be dried at 180°C for 4 hours to remove the moisture in the master batch. The raw materials are high-temperature melted and extruded through a single-screw extruder, the extrusion temperature is set to 260-275°C, the extruded melt is quickly attached to a cold roller by a patch device, and the cold roller is quickly cooled to form a cast sheet, and the temperature of the cold roller is set to 25°C.

[0053] (3) Longitudinal stretching process: the cast sheet is peeled off from the cold roller and then enters the longitudinal stretching machine, and then passes through the preheating roller, stretching roller, cooling roller, and tension roller to complete the longitudinal stretching under the action of a certain temperature and external force. The longitudinal stretching temperature is set to 78-84°C, and the stretching ratio is 2.8 times.

[0054] (4) Transverse stretching process: the cast sheet after longitudinal stretching is immediately pulled into the transverse stretching machine by a clamp for stretching, the transverse stretching preheating temperature is set to 95-100°C, the transverse stretching temperature is set to 100-120°C, the transverse stretching setting temperature is set to 175-240°C, and the transverse stretching cooling temperature is set to 110-150°C. After longitudinal stretching and transverse stretching, a biaxially stretched polyester film with certain mechanical properties and stable heat shrinkage rate is formed.

[0055] (5) Performance test: the flame retardant performance reaches the VTM-0 level of the UL94 standard, and the ultraviolet transmittance is less than 4.

[0056] The agricultural flame-retardant weather-resistant polyester film prepared by the method of the application has the following performance indicators (based on a 50 um thick film):

[0057]

[0058]

[0059] The above-described embodiments are only used to illustrate the technical ideas and characteristics of the present application, and to make those skilled in the art understand and implement the present application, and cannot be used to limit the patent scope of the present application, that is, any equivalent changes or modifications made according to the disclosed spirit of the present application still fall within the patent scope of the present application.

Claims

1. An agricultural flame retardant and weather-resistant polyester film, characterized in that: Contains the following components by mass:

2. The agricultural flame-retardant and weather-resistant polyester film according to claim 1, characterized in that: The high-phosphorus content phosphorus flame retardant is at least one of trihydroxypropylphosphine oxide, cyclooctylhydroxypropylphosphine oxide, and p-bis(2,2-cyanoethylphosphine oxide methyl)tetramethylbenzene.

3. The agricultural flame-retardant and weather-resistant polyester film according to claim 1, characterized in that: The antioxidant is at least one of hydroquinone, thiobisphenol and phosphite.

4. The agricultural flame-retardant and weather-resistant polyester film according to claim 1, characterized in that: The ultraviolet absorber is at least one of o-nitroaniline and p-cresol reactants, 2-hydroxy-4-n-octyloxybenzophenone, and monobenzoic acid resorcinol ester.

5. The agricultural flame-retardant and weather-resistant polyester film according to claim 1, characterized in that: The anti-hydrolysis agent is at least one of phenyl glycidyl ether, bisphenol A diglycidyl ether, and tetra(phenyl glycidyl ether)ethane.

6. The method for preparing the agricultural flame-retardant and weather-resistant polyester film according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) mixing the dried polyester chips, the silicon-containing polyester chips, the high-phosphorus content phosphorus flame retardant, the antioxidant, the ultraviolet absorber, and the anti-hydrolysis agent according to a ratio; (2) pre-crystallizing the mixed raw materials at 140-160° C. for 30-60 minutes, and then fully drying them at 160-180° C. for 4-6 hours; melting the raw materials at high temperature and extruding them through a single-screw extruder, with the extrusion temperature set at 260-275° C. The extruded melt is quickly attached to a cold roll with the aid of a sheet attachment device, and the melt is quickly cooled to form a cast sheet, with the temperature of the cold roll set at 25-30° C.; (3) Longitudinal stretching process: After the cast sheet enters the longitudinal stretching machine, it passes through the preheating roller, stretching roller, cooling roller, and tension roller, and is longitudinally stretched under a certain temperature and external force; (4) Transverse stretching process: After longitudinal stretching, the cast sheet enters the transverse stretching machine for stretching. After longitudinal stretching and transverse stretching, a biaxially oriented polyester film with certain mechanical properties and stable thermal shrinkage is formed; (5) Performance test: The flame retardant performance reaches VTM-0 level under UL94 standard, and the UV transmittance is less than 4.

7. The method for preparing the agricultural flame-retardant and weather-resistant polyester film according to claim 6, characterized in that: In step (3), the longitudinal stretching temperature is set to 78-84°C, and the stretching ratio is 2.8-3.4 times.

8. The method for preparing the agricultural flame-retardant and weather-resistant polyester film according to claim 6, characterized in that: In step (3), the transverse stretching preheating temperature is set to 95-100°C, the transverse stretching temperature is set to 100-120°C, the transverse stretching setting temperature is set to 175-240°C, and the transverse stretching cooling temperature is set to 110-150°C.

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