Hydrophobic and heat-resistant poly (butylene succinate) material and preparation method thereof

Abstract

The invention belongs to the technical field of biodegradable materials, and particularly relates to a hydrophobic and heat-resistant poly (butylene succinate) material and a preparation method thereof. The hydrophobic and heat-resistant poly (butylene succinate) material is prepared from the following raw material components in parts by weight: 95 to 98 parts of poly (butylene succinate), 0.5 to 3.0 parts of castor oil, 0.5 to 3.0 parts of isocyanate and 0.0 to 5.0 parts of an initiator, the preparation method comprises the following steps: mixing the poly (butylene succinate), the castor oil, the isocyanate and the initiator by using a twin-screw extruder, smelting, extruding, cooling and pelletizing. The preparation method comprises the following steps: introducing castor oil into a polybutylene succinate (PBS) molecular chain through isocyanate, and modifying PBS, so as to obtain the polybutylene succinate material with relatively high thermal deformation temperature and good hydrolysis resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of biodegradable materials, and in particular relates to a hydrophobic and heat-resistant polybutylene succinate material and a preparation method thereof. Background Art

[0002] Since the 20th century, humans have synthesized a variety of polymer materials, such as polyethylene, polypropylene, polyvinyl chloride, ABS, polystyrene, polyester, etc. The emergence of these materials has greatly facilitated people's lives. Entering the 21st century, with the development of online shopping, catering takeout, express delivery and other industries, the consumption of disposable plastic products has increased sharply. If these disposable plastic products cannot be degraded, they will remain in the environment for a long time, resulting in an increase in plastic waste in the environment year by year and increasing pollution. With the enhancement of people's environmental awareness, how to solve and suppress plastic waste has become one of the most concerned issues, making biodegradable materials gradually enter people's lives.

[0003] Biodegradable materials are materials that can be completely decomposed into low-molecular compounds by microorganisms (such as bacteria, fungi and algae) under appropriate and time-limited natural environmental conditions, which is of great significance to reducing plastic pollution. Among them, biodegradable polymer materials include aliphatic polyesters, polyester ethers, polyphosphazenes, polylactic acid, polycarbonate, polyanhydrides, polyamino acids, etc.

[0004] Polybutylene succinate is an important biodegradable material with the characteristics of high crystallinity, fast crystallization, high hardness, and high heat deformation temperature. It is widely used to prepare heat-resistant biodegradable products such as biodegradable heat-resistant lunch boxes and hot drink straws. However, the aliphatic ester bond binding force in the polybutylene succinate molecular chain is relatively weak (relative to aromatic polyesters), which is very easy to hydrolyze, resulting in the breakage of the polymer main chain, thereby affecting the mechanical properties of the material, which is manifested as the deterioration of the performance of the product macroscopically; on the other hand, polybutylene succinate products are exposed to the air and will slowly absorb moisture in the air, and the moisture content gradually rises to several thousand ppm. The increase in moisture content provides a good environment for the occurrence of hydrolysis reactions, which inevitably affects the shelf life and service life of the product. Therefore, how to control the hydrolysis aging rate of polybutylene succinate to avoid the mechanical properties of the product during normal storage and use, or even the situation that it cannot be used, is of great significance. Summary of the invention

[0005] The object of the present invention is to provide a hydrophobic and heat-resistant polybutylene succinate material in view of the above technical problems. Castor oil is introduced into the polybutylene succinate (PBS) molecular chain through isocyanate, so as to improve the hydrophobic property of the PBS material while ensuring a high heat deformation temperature thereof.

[0006] The hydrophobic and heat-resistant polybutylene succinate material in the technical solution of the present invention comprises the following raw material components in parts by weight: 95 to 98 parts of polybutylene succinate, 0.5 to 3.0 parts of castor oil, and 0.5 to 3.0 parts of isocyanate.

[0007] The main component of the castor oil is ricinoleic acid triglyceride, as shown in formula (1):

[0008]

[0009] The long carbon chain hydrophobic groups in ricinoleic acid triglyceride can protect the main chain of polybutylene succinate molecules, reduce the moisture absorption capacity of PBS materials, improve its hydrolysis resistance, and extend the shelf life and use period of PBS products; at the same time, after polybutylene succinate is modified with castor oil, a large number of carbon-carbon double bonds are still retained in the molecular chain. During the molding process of PBS products, cross-linking can be initiated by the high-temperature initiator pre-embedded in the material, thereby increasing the heat deformation temperature of the product and preventing the problem of a decrease in the heat deformation temperature of PBS due to copolymerization modification.

[0010] Furthermore, the polybutylene succinate contains other comonomers in a molar mass percentage of 0.0 to 5.0%.

[0011] Preferably, polybutylene succinate contains other comonomers in an amount of 0.1 to 3.0% by molar mass.

[0012] Furthermore, the other comonomer is one or more of 1,5-pentanedioic acid, 1,6-hexanedioic acid, 1,10-decanedioic acid, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,5-pentanediol, and 1,6-hexanediol, preferably 1,6-hexanedioic acid.

[0013] Furthermore, the carboxyl content in the polybutylene succinate is less than or equal to ≤30 mol / t.

[0014] Preferably, the melt flow rate (MFR) of polybutylene succinate at 190° C. and a load of 2.16 kg is 10 to 100 g / 10 min.

[0015] Furthermore, the isocyanate is one or more of diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and dicyclohexylmethane diisocyanate (HMDI).

[0016] Furthermore, the hydrophobic and heat-resistant polybutylene succinate material further comprises 0.0 to 5.0 parts of a high-temperature initiator.

[0017] Preferably, the amount of the high temperature initiator in the hydrophobic and heat-resistant polybutylene succinate material is 0.1 to 2.0 parts.

[0018] Furthermore, the high temperature initiator is a peroxide initiator, including but not limited to one or more of di-(tert-butylperoxyisopropyl)benzene (BIBP), di-tert-amyl peroxide (DTAP), and diisopropylbenzene peroxide (DCP).

[0019] Preferably, the preparation method of the above-mentioned polybutylene succinate comprises the following steps: adding butanediol to an esterification reactor, adding succinic acid, a comonomer and a catalyst in sequence under stirring, heating to 150-200° C. for esterification reaction, transferring the obtained esterified product to a polycondensation reactor, stirring and heating to 240-260° C., and then slowly reducing the pressure to an absolute pressure of about 100 Pa for polycondensation reaction; the molar mass ratio of butanediol to succinic acid is 1.0-1.5:1.0; the catalyst includes but is not limited to one or more of tetrabutyl titanate, tetraisopropyl titanate, complex titanium, and Ti / Si composite; the mass of the catalyst is 0.005-0.015% of the sum of the mass of butanediol, succinic acid and the comonomer.

[0020] The present invention also provides a method for preparing the hydrophobic and heat-resistant polybutylene succinate material, comprising the following steps: using a twin-screw extruder to mix polybutylene succinate, castor oil, isocyanate and a high-temperature initiator, melting, extruding, cooling and pelletizing.

[0021] Preferably, the polybutylene succinate is dried before use.

[0022] Furthermore, the aspect ratio of the twin-screw extruder is greater than or equal to 48.

[0023] Furthermore, the preparation method is to add polybutylene succinate to a feeding silo of a twin-screw extruder, add castor oil to a storage tank A connected to a melting section of the twin-screw extruder, add isocyanate and a high-temperature initiator to a storage tank B connected to a plasticizing section of the twin-screw extruder, and start the twin-screw extruder for mixing.

[0024] Furthermore, the preparation method uses two twin-screw extruders in series, wherein polybutylene succinate and castor oil are uniformly mixed in the first twin-screw extruder, and the mixture of polybutylene succinate and castor oil is uniformly mixed with diisocyanate and a high-temperature initiator in the second extruder.

[0025] Furthermore, the temperature of the twin-screw extruder for mixing, melting and extruding is 120-180°C.

[0026] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0027] (1) Castor oil is introduced into the molecular chain of polybutylene succinate (PBS) through isocyanate to modify PBS and obtain a polybutylene succinate material with a higher heat deformation temperature and good hydrolysis resistance;

[0028] (2) The long carbon chain hydrophobic group in ricinoleic acid triglyceride can protect the main chain of polybutylene succinate molecule, reduce the moisture absorption capacity of PBS material, improve its hydrolysis resistance, and extend the shelf life and use period of PBS products;

[0029] (3) After castor oil is modified with polybutylene succinate, a large number of carbon-carbon double bonds are still retained in the molecular chain. During the molding process of PBS products, cross-linking can be induced by a high-temperature initiator to increase the heat deformation temperature of the product and prevent the problem of PBS's heat deformation temperature decreasing due to copolymerization modification.

[0030] (4) The preparation method of the hydrophobic and heat-resistant polybutylene succinate material is simple and easy to operate, and is suitable for industrial application. DETAILED DESCRIPTION

[0031] The technical scheme of the present invention is further described below by specific embodiments. It should be understood that the specific embodiments described herein are only used to help understand the present invention and are not intended to be used for specific limitations of the present invention. Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commonly used raw materials in the art, and the methods used in the embodiments are all conventional methods in the art.

[0032] The preparation method of polybutylene succinate in the following embodiment comprises the following steps: adding butanediol to an esterification reactor, adding succinic acid, a comonomer and tetrabutyl titanate in sequence under stirring, heating to 180°C for esterification reaction, reacting until no esterification water is generated, transferring the obtained esterified product to a polycondensation reactor, heating to 250°C under stirring, and then slowly reducing the pressure to an absolute pressure of 100 Pa for polycondensation reaction; the molar mass ratio of butanediol to succinic acid is 1.0:1.0; the mass of tetrabutyl titanate is 0.01% of the sum of the masses of butanediol, succinic acid and the comonomer; the carboxyl content in the obtained polybutylene succinate is less than or equal to ≤30 mol / t; and the commercially available PBS comes from Mitsubishi Chemical.

[0033] Example 1

[0034] The preparation method of the hydrophobic and heat-resistant polybutylene succinate material of the present embodiment comprises the following steps: adding 97.8 parts of dried polybutylene succinate (MFR is 30-40 g / 10 min) into a feeding silo of a twin-screw extruder, adding 1.2 parts of castor oil into a storage tank A connected to a melting section of the twin-screw extruder, adding 1.0 parts of MDI and 0.5 parts of dicumyl peroxide into a storage tank B connected to a plasticizing section of the twin-screw extruder, setting the temperature of the twin-screw extruder to 120-180° C., increasing the temperature from the feed end to the discharge end, starting the twin-screw extruder for mixing, melting and extruding, and pelletizing after cooling.

[0035] Example 2

[0036] The preparation method of the hydrophobic and heat-resistant polybutylene succinate material of the present embodiment comprises the following steps: adding 97.3 parts of dried polybutylene succinate (MFR is 10-20 g / 10 min) into the feeding bin of a twin-screw extruder, adding 1.2 parts of castor oil into a storage tank A connected to the melting section of the twin-screw extruder, adding 1.5 parts of TDI into a storage tank B connected to the plasticizing section of the twin-screw extruder, setting the temperature of the twin-screw extruder to 120-180° C., increasing the temperature from the feed end to the discharge end, starting the twin-screw extruder for mixing, melting, and extruding, and pelletizing after cooling.

[0037] Example 3

[0038] The preparation method of the hydrophobic and heat-resistant polybutylene succinate material of the present embodiment comprises the following steps: adding 96.0 parts of dried polybutylene succinate (MFR is 80-100 g / 10 min) into a feeding silo of a twin-screw extruder, adding 1.5 parts of castor oil into a storage tank A connected to a melting section of the twin-screw extruder, adding 2.0 parts of HDI into a storage tank B connected to a plasticizing section of the twin-screw extruder, setting the temperature of the twin-screw extruder to 120-180° C., increasing the temperature from the feed end to the discharge end, starting the twin-screw extruder for mixing, melting, and extrusion, and pelletizing after cooling.

[0039] Example 4

[0040] The preparation method of the hydrophobic and heat-resistant polybutylene succinate material of the present embodiment comprises the following steps: using two tandem twin-screw extruders, uniformly mixing 95.5 parts of dried polybutylene succinate (MFR of 50-60 g / 10 min, containing 1.0% of 1,6-hexanodioic acid) with 2.5 parts of castor oil in the first twin-screw extruder, uniformly mixing the mixture of polybutylene succinate and castor oil with 2.0 parts of MDI in the second extruder, setting the temperature of the twin-screw extruder to 120-180° C., increasing the temperature from the feed end to the discharge end, starting the twin-screw extruder for mixing, melting, and extruding, and pelletizing after cooling.

[0041] Example 5

[0042] The preparation method of the hydrophobic and heat-resistant polybutylene succinate material of the present embodiment comprises the following steps: adding 97.8 parts of dried polybutylene succinate (MFR is 30-40 g / 10 min) into the feeding bin of a twin-screw extruder, adding 0.2 parts of castor oil into a storage tank A connected to the melting section of the twin-screw extruder, adding 1.0 parts of MDI into a storage tank B connected to the plasticizing section of the twin-screw extruder, setting the temperature of the twin-screw extruder to 120-180° C., increasing the temperature from the feed end to the discharge end, starting the twin-screw extruder for mixing, melting, and extrusion, and pelletizing after cooling.

[0043] Example 6

[0044] The preparation method of the hydrophobic and heat-resistant polybutylene succinate material of the present embodiment comprises the following steps: adding 97.8 parts of dried polybutylene succinate (MFR is 30-40 g / 10 min) into the feeding bin of a twin-screw extruder, adding 3.5 parts of castor oil into a storage tank A connected to the melting section of the twin-screw extruder, adding 1.0 part of MDI into a storage tank B connected to the plasticizing section of the twin-screw extruder, setting the temperature of the twin-screw extruder to 120-180° C., increasing the temperature from the feed end to the discharge end, starting the twin-screw extruder for mixing, melting, and extruding, and pelletizing after cooling.

[0045] Comparative Example 1

[0046] The preparation method of the hydrophobic and heat-resistant polybutylene succinate material of the comparative example comprises the following steps: adding 97.8 parts of dried polybutylene succinate (MFR is 30-40 g / 10 min) into the feeding silo of the twin-screw extruder, adding 1.0 part of MDI into the storage tank B connected to the plasticizing section of the twin-screw extruder, setting the temperature of the twin-screw extruder to 120-180° C., increasing it successively from the feed end to the discharge end, starting the twin-screw extruder for mixing, melting and extruding, and pelletizing after cooling.

[0047] The water absorption rate and heat deformation temperature test of the hydrophobic and heat-resistant polybutylene succinate materials obtained in the above embodiments and comparative examples were performed: the temperature of the constant temperature and humidity chamber was set to 65°C and the humidity was set to 85% during the water absorption rate test. After the temperature and humidity in the constant temperature and humidity chamber were balanced, the obtained polybutylene succinate material was diluted and placed in the constant temperature and humidity chamber, exposed for 48 hours, and then taken out to measure the moisture content. The test method was based on "GB / T 30294-2013 Polybutylene Succinate"; the heat deformation temperature test was based on "GB / T 30294-2013 Polybutylene Succinate" 5.14 Load Deformation Temperature, and the injection molding temperature of the sample was 180°C; the test results are shown in Table 1:

[0048] Table 1 Polybutylene Succinate Material Properties

[0049] MFR(g / 10min) Water absorption (%) Heat deformation temperature(℃) Example 1 4～6 0.216 85 Example 2 4～6 0.219 82 Example 3 6～8 0.215 83 Example 4 3～4 0.218 85 Example 5 4～6 0.396 79 Example 6 4～6 0.305 76 Comparative Example 1 4～6 0.456 78 Commercially available PBS 3～10 0.489 77

[0050] In Example 1-4, castor oil is introduced into the PBS molecular chain through isocyanate to modify PBS, thereby obtaining a PBS material with a higher heat deformation temperature and good hydrolysis resistance. In Example 5, a small amount of castor oil is used to modify PBS, and the water absorption rate of the obtained PBS material is increased, the heat deformation temperature is reduced, and the hydrolysis resistance and heat resistance are reduced. In Example 6, an excessive amount of castor oil is used to modify PBS, which is difficult to be completely combined with the main chain of the PBS molecule, and the remaining castor oil will precipitate or leach on the surface of the product, affecting the product's food contact certification. In Comparative Example 1, castor oil is not used to modify PBS, and the obtained PBS material has a higher water absorption rate and faster performance aging.

[0051] Finally, it should be noted that the specific embodiments described herein are merely examples of the spirit of the present invention, and are not intended to limit the implementation methods of the present invention. Those skilled in the art of the present invention may make various modifications or supplements to the described embodiments or replace them in similar ways. It is not necessary and impossible to provide all examples of all implementation methods here. However, these obvious changes or modifications derived from the essential spirit of the present invention still fall within the scope of protection of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A hydrophobic, heat-resistant polybutylene succinate material, characterized in that: The invention comprises the following raw material components in parts by weight: 95-98 parts of polybutylene succinate, 0.5-3.0 parts of castor oil and 0.5-3.0 parts of isocyanate.

2. The hydrophobic, heat-resistant polybutylene succinate material according to claim 1, characterized in that: The polybutylene succinate contains other comonomers in a molar mass percentage of 0.0 to 5.0%.

3. The hydrophobic, heat-resistant polybutylene succinate material according to claim 2, characterized in that: The other comonomers are one or more of 1,5-pentanedioic acid, 1,6-hexanedioic acid, 1,10-decanedioic acid, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,5-pentanediol, and 1,6-hexanediol.

4. The hydrophobic, heat-resistant polybutylene succinate material according to claim 1, characterized in that: The carboxyl content in polybutylene succinate is less than or equal to ≤30 mol / t.

5. The hydrophobic, heat-resistant polybutylene succinate material according to claim 1, characterized in that: The isocyanate is one or more of diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate.

6. The hydrophobic, heat-resistant polybutylene succinate material according to claim 1, characterized in that: The hydrophobic and heat-resistant polybutylene succinate material also includes 0.0 to 5.0 parts of an initiator.

7. A method for preparing the hydrophobic, heat-resistant polybutylene succinate material as claimed in claim 1, characterized in that: The following steps are involved: The polybutylene succinate, castor oil, isocyanate and initiator are mixed, melted, extruded, cooled and pelletized using a twin-screw extruder.

8. The preparation method according to claim 7, characterized in that: Add polybutylene succinate to the feeding silo of the twin-screw extruder, add castor oil to the storage tank A connected to the melting section of the twin-screw extruder, add isocyanate and initiator to the storage tank B connected to the plasticizing section of the twin-screw extruder, and start the twin-screw extruder for mixing.

9. The preparation method according to claim 7, characterized in that: Two twin-screw extruders are used in series. Polybutylene succinate and castor oil are uniformly mixed in the first twin-screw extruder, and the mixture of polybutylene succinate and castor oil, diisocyanate and initiator are uniformly mixed in the second extruder.

10. The preparation method according to claim 7, characterized in that: The temperature of the twin-screw extruder for mixing, melting and extruding is 120-180°C.

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