Hydrophobic modified polyester PET and preparation method thereof

Abstract

The invention belongs to the field of high polymer materials. The invention provides hydrophobic modified polyester PET and a preparation method thereof, the hydrophobic modified polyester PET comprises the following components: polyester PET resin, an organic fluorosilicone-allyl glycidyl ether hydrophobic modification copolymer and an antioxidant, the preparation method of the hydrophobic modified polyester PET is also provided, the components are uniformly mixed according to the proportion to obtain a mixed material, and the mixed material is subjected to extrusion molding to obtain the hydrophobic modified polyester PET. Wherein the copolymer for hydrophobic modification of the organic fluorosilicone-allyl glycidyl ether is added in a form of being dissolved in an organic medium to form a polymer solution; and standing the mixed material for 1-2 hours, adding the mixed material into a double-screw extruder, carrying out melting reaction and extrusion, and removing and recovering the solvent and unreacted residual monomers in the raw materials through a vacuumizing exhaust device to prepare the hydrophobic polyester PET. The hydrophobic modified polyester PET is good and lasting in hydrophobic property, simple in preparation process and relatively low in cost, and can be applied to multiple fields such as textile and clothing, packaging materials, building materials, electronic and electric appliances, automobile manufacturing and the like.

Description

Technical Field

[0001] The invention belongs to the field of polymer materials, and in particular relates to a hydrophobically modified polyester (PET) and a preparation method thereof. Background Art

[0002] Existing polyester PET (polyethylene terephthalate) is a widely used thermoplastic polyester. It has the advantages of good mechanical properties, chemical resistance and transparency. Traditional PET has important applications in many fields, such as beverage bottles, fibers, films, etc.

[0003] However, polyester PET is a highly hydrophilic material that easily absorbs moisture when in contact with water or in a high humidity environment. The absorption of moisture will cause many properties of PET materials to deteriorate, which becomes an obvious limitation in certain specific application scenarios. For example, in outdoor applications, PET materials easily absorb moisture, resulting in a decrease in its mechanical properties, poor dimensional stability, and easy breeding of microorganisms; in fiber applications, PET fibers will swell after absorbing water, which will deteriorate the dimensional stability of the fibers and cause fabric deformation; in the field of electronic appliances, electronic components are very sensitive to humidity. When PET is used for some humidity-sensitive electronic component packaging or insulation materials, the absorption of moisture may affect the performance and service life of electronic components. The hydrophilicity of ordinary PET materials makes it not well used in the packaging of electronic components or as insulation materials; the presence of water will accelerate the aging process of the material, such as hydrolysis reaction. For PET materials, the absorbed moisture will trigger the hydrolysis of ester bonds, resulting in a decrease in the molecular weight of the material, and then the mechanical properties of the material such as strength and toughness will decrease.

[0004] In order to overcome the hydrophilicity of PET, hydrophobic modification technology came into being. The water resistance of PET can be significantly improved through modification, so that PET materials can still maintain good performance in humid environments. For example, in the field of fibers, hydrophobic PET fibers can be used to make outdoor clothing, tents, etc. Even in rainy environments, they will not become heavy or lose their warmth retention properties due to a large amount of water absorption. Hydrophobic-modified PET can expand its application in fields such as medical and food packaging that require high waterproof properties. In the medical field, hydrophobic PET can be used to make some medical device packaging that requires waterproofing or carriers for implantable materials. In the field of food packaging, it can prevent external moisture from entering the packaging and extend the shelf life of food.

[0005] There are mainly the following methods for hydrophobic modification of hydrophobic polyester PET:

[0006] 1. Blending modification: PET is blended with other hydrophobic polymers, such as polyolefins, fluoropolymers, etc. The hydrophobicity of the blend can be controlled by adjusting the blending ratio and processing conditions, but the original physical properties of the polyester PET resin are greatly changed.

[0007] 2. Surface coating: Apply a hydrophobic coating on the surface of PET, such as fluorocarbon coating, silane coupling agent, etc. This method can significantly improve the surface hydrophobicity of PET, but the durability of the coating may be a problem.

[0008] 3. Copolymerization modification method: copolymerize active modifiers containing low surface energy such as silicon and fluorine, such as polyhydroxyfluorosilicone oil, with the polymerization monomers of polyester PET to form hydrophobically modified copolyester. This method can firmly bind the hydrophobic groups to the PET molecules, thereby obtaining lasting hydrophobic properties, but the cost is relatively high.

[0009] Therefore, it is necessary to study modified polyester PET with hydrophobic properties that has low cost, simple process and meets production and manufacturing needs. Summary of the invention

[0010] In order to solve the above problems, the present invention provides a hydrophobically modified polyester PET and a preparation method thereof. The hydrophobically modified polyester PET has good and lasting hydrophobicity, a simple preparation process, and low cost, and can be applied to textiles and clothing, packaging materials, building materials, electronic appliances, automobile manufacturing and other fields.

[0011] The object of the present invention is to provide a hydrophobically modified polyester PET, comprising the following components in parts by weight:

[0012] Polyester PET resin 90-96 parts

[0013] 4-15 parts of organic fluorine silicon-allyl glycidyl ether copolymer for hydrophobic modification

[0014] Antioxidant 0.2-1.0 part.

[0015] The organic fluorine silicon-allyl glycidyl ether copolymer component for hydrophobic modification introduced by the present invention has, in addition to the structural units of the hydrophobic long polysiloxane side chain and the methacrylic acid fluorine-containing monomer with the fluorine-containing side group, the epoxy group brought in by the allyl glycidyl ether monomer that chemically reacts with the carboxyl group of the polyester PET. The synergistic effect of the fluorine-containing structural unit and the silicon-containing organic long side chain enables the modified polyester PET to obtain better and lasting hydrophobic properties with a relatively small addition amount of the organic fluorine silicon-allyl glycidyl ether copolymer for hydrophobic modification, and less changes are made to other properties of the polyester PET substrate.

[0016] Preferably, the antioxidant is at least one of antioxidant 1010, antioxidant 168, antioxidant 1076, and antioxidant DLTP.

[0017] Furthermore, the above-mentioned organic fluorine silicon-allyl glycidyl ether copolymer for hydrophobic modification includes the following polymerized monomers in parts by weight:

[0018]

[0019] Preferably, the relative molecular mass of the monovinyl polysiloxane is 1250-5000.

[0020] The methacrylate fluorinated monomer is at least one of dodecafluoroheptyl methacrylate, trifluoroethyl methacrylate, hexafluorobutyl methacrylate, and octafluoropentyl methacrylate.

[0021] Furthermore, the preparation method of the above-mentioned organic fluorine silicon-allyl glycidyl ether copolymer for hydrophobic modification comprises the following steps:

[0022] (1) adding 60-80% of the total amount of the organic medium into a polymerization reactor, heating to 60-100° C., and then adding 50-85% of the initiator to obtain an initiator-containing solution;

[0023] (2) uniformly mixing the polymerizable monomer monovinyl polysiloxane, the methacrylate fluorinated monomer, allyl glycidyl ether, styrene and an organic medium accounting for 10-20% of the total amount of the organic medium to obtain a mixed solution;

[0024] (3) adding the mixed solution obtained in step (2) dropwise to the solution containing the initiator in step (1) for 2-4 hours, and keeping the mixture warm for 0.5-3 hours after the addition is complete;

[0025] (4) adding the remaining amount of the initiator and the remaining amount of the organic medium to obtain a mixed solution, dropwise adding the mixed solution to the system after heat preservation in step (3), the addition time is 0.5-1 hour, the temperature is kept constant for 2.5-4 hours after the addition is completed, and the mixture is cooled to obtain a solution of an organic fluorosilicon-allyl glycidyl ether copolymer for hydrophobic modification dissolved in an organic medium.

[0026] Preferably, the initiator is at least one of azobisisobutyronitrile, azobisisoheptylnitrile, benzoyl peroxide, diisopropylbenzene peroxide, di-tert-butyl peroxide, dodecyl peroxide, and tert-butyl perbenzoate. The amount of the initiator is 0.1%-2% of the total mass of the polymerized monomers based on the total mass of the homogeneous solution of the preparation system of the organic fluorine silicon-allyl glycidyl ether hydrophobically modified copolymer.

[0027] The organic medium is at least one of toluene, xylene and ethylbenzene. Based on the total mass of the homogeneous solution of the system for preparing the organic fluorosilicon-allyl glycidyl ether hydrophobically modified copolymer, the amount of the organic medium is 30%-70% of the total mass of the homogeneous solution.

[0028] The present invention also aims to provide a method for preparing the above-mentioned hydrophobically modified polyester PET, comprising the following steps:

[0029] (1) mixing polyester PET resin, organic fluorine silicon-allyl glycidyl ether copolymer for hydrophobic modification, and antioxidant in the above ratio to obtain a mixed material;

[0030] wherein the organic fluorosilicone-allyl glycidyl ether copolymer for hydrophobic modification is added in the form of a polymer solution formed by dissolving in an organic medium;

[0031] (2) The mixed material obtained in step 1 is allowed to stand for 1-2 hours, and then added to a twin-screw extruder for melt reaction and extrusion. The solvent and unreacted residual monomers in the raw material are removed and recovered by a vacuum exhaust device of the twin-screw extruder to obtain a hydrophobic polyester PET.

[0032] The present invention adopts the reaction extrusion technology, so that the organic fluorine silicon-allyl glycidyl ether copolymer for hydrophobic modification is connected with the polyester PET matrix through chemical bonds to prevent the phase separation of the system, the molecular chain movement of the introduced polysiloxane long side chain is relatively less restricted, the chain activity ability is better, and the polysiloxane long side chain migrates to the polyester PET material surface and distributes more widely. The organic fluorine silicon-allyl glycidyl ether copolymer for hydrophobic modification of the present invention is added in the form of a polymer solution, and the solvent and unreacted residual monomers in the raw material are removed and recovered by a vacuum exhaust device.

[0033] Furthermore, in step (1), the mass ratio of the organic fluorosilicone-allyl glycidyl ether copolymer for hydrophobic modification to the organic medium is 1:0.3-3.

[0034] Preferably, the heating temperature of the twin-screw extruder is set to 150° C.-270° C., and the main screw speed is set to 80-150 rpm.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The present invention uses a free radical solution polymerization method to prepare an organic fluorosilicone-allyl glycidyl ether hydrophobically modified copolymer from monovinyl polysiloxane, a methacrylate fluorine-containing monomer, allyl glycidyl ether, and styrene. The hydrophobically modified copolymer component has a structure having not only a hydrophobic polysiloxane long side chain and a methacrylic acid fluorine-containing monomer with a fluorine-containing side group, but also an epoxy group introduced by the allyl glycidyl ether monomer that chemically reacts with the carboxyl group of the polyester PET;

[0037] (2) Compared with the method of introducing polyfluorosilicone blocks into the molecular weight of polyester PET by copolymerization, the molecular chain movement of the long side chains of polysiloxane introduced into polyester PET in the present invention is relatively less restricted, the chain activity is better, and the long side chains of polysiloxane migrate to the surface of polyester PET material more widely;

[0038] (3) The synergistic effect of the fluorine-containing structural unit and the silicon-containing organic long side chain enables the modified polyester PET to obtain better and more durable hydrophobic properties with a relatively small amount of organic fluorine silicon-allyl glycidyl ether hydrophobic modification copolymer added, and has little effect on other properties of the polyester PET substrate;

[0039] (4) The present invention realizes that the organic fluorine silicon-allyl glycidyl ether hydrophobically modified copolymer, polyester PET, antioxidant, etc. are connected to the polyester PET matrix through chemical bonds to prevent phase separation of the system by reacting and extruding the organic fluorine silicon-allyl glycidyl ether hydrophobically modified copolymer, polyester PET, antioxidant, etc. through a twin-screw reaction extruder;

[0040] (5) The process flow of the present invention is simple and the cost is low, which can meet the needs of mass production and manufacturing, and can be applied to many fields such as textiles and clothing, packaging materials, building materials, electronic appliances, and automobile manufacturing. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The organic fluorine silicon-allyl glycidyl ether copolymer for hydrophobic modification is prepared by polymerization of monovinyl polysiloxane, methacrylate fluorine-containing monomer, allyl glycidyl ether and styrene.

[0043] The preparation method of an organic fluorine silicon-allyl glycidyl ether copolymer for hydrophobic modification is as follows: under the protection of inert gas, an organic medium accounting for 60-80wt% of the total amount of the organic medium is added to a polymerization reactor and heated to 60-100°C; an initiator accounting for 50-85% of the total amount of the initiator is added to the polymerization reactor to obtain an initiator-containing solution; then the polymerization monomer and the organic medium accounting for 10-20wt% of the total amount of the organic medium are uniformly mixed to obtain a mixed solution, the mixed solution is dripped into the initiator-containing solution for 2-4 hours, and the temperature is kept for 0.5-3 hours after the dripping is completed; the remaining initiator is uniformly mixed with the remaining organic medium, and dripped into the system for 0.5-1 hour, and the temperature is kept constant for 3 hours. After cooling to room temperature, a resin solution of the organic fluorine silicon-allyl glycidyl ether copolymer for hydrophobic modification is obtained, which is used for further preparation of hydrophobically modified polyester PET.

[0044] The preparation method of hydrophobically modified polyester PET comprises the following preparation steps:

[0045] S1, the prepared solution of the organic fluorine silicon-allyl glycidyl ether copolymer for hydrophobic modification is ready for use;

[0046] S2, after the polyester PET resin, the solution of the organic fluorine silicon-allyl glycidyl ether hydrophobically modified copolymer and the antioxidant are uniformly mixed according to the ratio, the mixture is allowed to stand for 1-2 hours, and then added into the twin-screw extruder;

[0047] S3, setting the heating temperature of the twin-screw extruder to 150°C-270°C, setting the main screw speed to 80-150rpm, extruding the mixed raw materials through the twin-screw extruder through melt reaction, removing and recovering the solvent and unreacted residual monomers in the raw materials through a vacuum exhaust device, and finally granulating to obtain the hydrophobic PET modified material.

[0048] Example 1

[0049] 1. Preparation of organic fluorine silicon-allyl glycidyl ether copolymer solution for hydrophobic modification

[0050] Under nitrogen protection, 1950.0g of toluene was added to the experimental reactor and heated to 65°C. 10.5g of initiator AIBN was added to the experimental reactor and stirred to dissolve it to obtain an initiator solution. Then 750.0g of monovinyl polysiloxane (Vi-PDMS, relative molecular weight 2000), 75.0g of hexafluorobutyl methacrylate, 43.0g of allyl glycidyl ether, 617.0g of styrene, and 558.0g of toluene were prepared. After the solution is evenly mixed, it is added dropwise to the above-mentioned experimental reactor, and the addition time is controlled to about 4 hours. After the addition is completed, the temperature is raised to 70°C and kept warm for 3 hours; 4.5g of initiator AIBN and 279g of toluene are prepared into a uniform initiator solution, and then added dropwise to the above-mentioned experimental reactor, and the time is controlled for 1 hour. Finally, the temperature is raised to 95°C, and the reaction is carried out at a constant temperature for 3 hours. Finally, it is cooled to room temperature to obtain organic fluorosilicone-allyl glycidyl ether hydrophobic modification copolymer resin solution 1# for standby use.

[0051] 2. Preparation of hydrophobically modified polyester PET 1#

[0052] 4800g of polyester PET resin, 572g of resin solution 1# of organic fluorine silicon-allyl glycidyl ether hydrophobically modified copolymer, 5g of antioxidant 1010, and 10g of antioxidant 168 were fully stirred in a mixer and then allowed to stand for 1 hour, and then added into a covered feeding funnel of a twin-screw reaction extruder with a vacuum exhaust device. The twin-screw reaction extruder was a Φ35-type parallel co-rotating meshing twin-screw extruder with a total of thirteen barrels and an aspect ratio of 56. The barrel temperature of the extruder was set to 150°C-270°C, the main engine screw speed was set to 100rpm, and a vacuum exhaust chamber and a matching condensation recovery device were opened on the 9th and 12th barrels away from the feed port to vacuum remove and recover the solvent and unreacted residual monomers in the raw materials. The blended materials were melt-reacted and extruded by the twin-screw reaction extruder, and then granulated by an air-cooled die face pelletizing device to obtain hydrophobic polyester PET 1#.

[0053] Example 2 Preparation of hydrophobically modified polyester PET 2#

[0054] 4700 g of polyester PET resin, 857 g of resin solution 1# of organic fluorosilicon-allyl glycidyl ether hydrophobically modified copolymer, 5 g of antioxidant 1010 and 10 g of antioxidant 168 were prepared through the same preparation process as in Example 1 to obtain hydrophobic polyester PET modified material 2#.

[0055] Hydrophobic performance test

[0056] Comparative Example 1 is polyester PET pellets.

[0057] The hydrophobic polyester PET modified materials 1# and 2# pellets prepared in Examples 1 and 2 and the polyester PET pellets of Comparative Example 1 were vacuum dried in a vacuum oven at 100°C for 12 hours, and then hot pressed to form smooth polyester sheets. After cooling, the prepared polyester sheet samples were immersed in ethyl acetate solvent and ultrasonically treated for 10 minutes, and then the polyester sample surface was rinsed with anhydrous ethanol and dried. Finally, the contact angle of the dried polyester sample surface with a water droplet was tested according to the test method of the national standard "GB / T 26490-2011 Nanomaterial Super Amphiphobic Performance Test Method". The test results are shown in Table 1.

[0058] Table 1 Water drop contact angle test results of Examples 1-2 and Comparative Example 1

[0059] Serial number Test sample number Water drop contact angle° 1 Comparative Example 1 72 2 Example 1 93 3 Example 2 100

[0060] As can be seen from Table 1, compared with pure polyester PET, the sample of the hydrophobic polyester PET modified material prepared by the present invention has a contact angle greater than 90° even after being soaked in the organic solvent ethyl acetate, which shows that the hydrophobic property is more durable because the fluorosilicon hydrophobic structure of the hydrophobic polyester PET of the present invention is bonded to the polyester PET matrix through a chemical bond. The hydrophobic modified polyester PET modified material of the present invention has excellent hydrophobic property, simple preparation process, low cost, and is easy to industrialize.

[0061] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the relevant technical field may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also belong to the scope of the present invention and should be defined by the claims.

Claims

1. A hydrophobically modified polyester PET, characterized in that: The composition comprises the following components in parts by weight: Polyester PET resin 90-96 parts 4-15 parts of organic fluorine silicon-allyl glycidyl ether hydrophobically modified copolymer Antioxidant 0.2-1.0 part.

2. The hydrophobically modified polyester PET according to claim 1, characterized in that: The organic fluorine silicon-allyl glycidyl ether copolymer for hydrophobic modification comprises the following polymerized monomers in mass fractions:

3. The hydrophobically modified polyester PET according to claim 2, characterized in that: The relative molecular mass of the monovinyl polysiloxane is 1250-5000.

4. The hydrophobically modified polyester PET according to claim 2, characterized in that: The methacrylate fluorinated monomer is at least one of dodecafluoroheptyl methacrylate, trifluoroethyl methacrylate, hexafluorobutyl methacrylate, and octafluoropentyl methacrylate.

5. The hydrophobically modified polyester PET according to claim 2, characterized in that: The preparation method of the organic fluorine silicon-allyl glycidyl ether copolymer for hydrophobic modification, The following steps are included: (1) adding 60-80% of the total amount of the organic medium into a polymerization reactor, heating to 60-100° C., and then adding 50-85% of the initiator to obtain an initiator-containing solution; (2) uniformly mixing the polymerizable monomer with an organic medium accounting for 10-20% of the total amount of the organic medium to obtain a mixed solution; (3) adding the mixed solution obtained in step (2) dropwise to the solution containing the initiator in step (1) for 2-4 hours, and keeping the mixture warm for 0.5-3 hours after the addition is complete; (4) adding the remaining amount of the initiator and the remaining amount of the organic medium to obtain a mixed solution, dropwise adding the mixed solution to the system after heat preservation in step (3), the adding time being 0.5-1 hour, keeping the temperature constant for 2.5-4 hours after the addition is completed, and cooling to obtain a resin solution of an organic fluorosilicone-allyl glycidyl ether copolymer for hydrophobic modification.

6. The hydrophobically modified polyester PET according to claim 5, characterized in that: The initiator is at least one of azobisisobutyronitrile, azobisisoheptylnitrile, benzoyl peroxide, diisopropylbenzene peroxide, di-tert-butyl peroxide, dodecyl peroxide, and tert-butyl perbenzoate. The amount of the initiator is 0.1%-2% of the total mass of the polymerized monomers, based on the total mass of the polymerized monomers in the homogeneous solution of the preparation system of the organic fluorosilicon-allyl glycidyl ether hydrophobically modified copolymer.

7. The hydrophobically modified polyester PET according to claim 5, characterized in that: The organic medium is at least one of toluene, xylene and ethylbenzene. The amount of the organic medium is 30%-70% of the total mass of the homogeneous solution based on the total mass of the homogeneous solution prepared by the organic fluorosilicon-allyl glycidyl ether hydrophobically modified copolymer.

8. A method for preparing the hydrophobically modified polyester PET according to any one of claims 1 to 7, characterized in that: The following steps are included: (1) mixing polyester PET resin, organic fluorine silicon-allyl glycidyl ether copolymer for hydrophobic modification, and antioxidant in a uniform ratio to obtain a mixed material; wherein the organic fluorosilicone-allyl glycidyl ether copolymer for hydrophobic modification is added in the form of a polymer solution formed by dissolving in an organic medium; (2) The mixed material obtained in step 1 is allowed to stand for 1-2 hours, and then added to a twin-screw extruder for melt reaction extrusion. The solvent and unreacted residual monomers in the raw material are removed and recovered by a vacuum exhaust device to obtain a hydrophobic polyester PET.

9. The preparation method according to claim 8, characterized in that: In step (2), the heating temperature of the twin-screw extruder is set to 150° C.-270° C., and the main screw speed is set to 80-150 rpm.

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