PBAT (poly (butylene adipate-co-terephthalate)) alloy, preparation method of PBAT alloy, foamed sheet and preparation method of foamed sheet

Abstract

The invention discloses a PBAT alloy and a preparation method thereof, and a foamed sheet and a preparation method thereof. The PBAT alloy comprises the following components: PBAT resin, a chain extender, a plasticizer, a primary amine compound and an alkaline compound. The low-molecular-weight PBAT resin with more terminal carboxyl groups and terminal hydroxyl reactive groups is adopted to react with the added primary amine compound to generate a tertiary amine compound which can be used as a CO2 responsive polymer to absorb carbon dioxide released by an alkaline compound in a system, and the prepared modified particles are directly used for mold pressing foaming, so that the foaming efficiency is improved. CO2 is released as a foaming agent in the heating process, and the foaming ratio of the foamed sheet prepared by the method can reach 15-25 times.

Description

Technical Field

[0001] The present invention belongs to the field of degradable plastics, and particularly relates to a PBAT alloy with good compatibility with CO 2 and a foaming material with good compatibility. Background Art

[0002] With the strengthening of people's awareness of ecological environmental protection and policy requirements, the environmental pollution problems brought by traditional foaming materials have attracted everyone's attention. Biodegradable foams have biocompatibility, biodegradability and renewability, and are an environmentally friendly material, which has received extensive attention from countries around the world. Biodegradable polymer foam materials mainly use materials such as cellulose, polylactic acid, starch, protein, chitosan, PBAT, and PBS, and usually have three types: extrusion foaming, autoclave foaming and compression molding foaming.

[0003] Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable material with excellent properties. The degradation rate is greater than 90% after 180 days in a composting environment, and it has good toughness and processability, and can be used to prepare soft foaming materials. However, its low melt strength limits its foaming ratio, and it is easy to have pore connection and bubble breakage during the foaming process, forming a large number of open-cell structures, thus limiting its application in the foaming field.

[0004] CN118185251A discloses a high-ratio PBAT-based foaming material and its preparation method. This alloy is composed of PBAT, PCL, PBS, a nucleating agent and an ADR epoxy chain extender. After mixing, a blend is obtained, and then the obtained blend is molded. After molding and saturation for a period of time, pressure is released for foaming to obtain a high-ratio PBAT-based foaming material. This method first prepares modified particles, then autoclave foams, and finally steam compression molds, and the preparation method is relatively complex and not conducive to industrialization.

[0005] CN118290808B discloses an antibacterial PBAT foaming material and its preparation method, which is prepared by melt mixing a modified copolymer, a modified filler and azodicarbonamide, then pressure-holding foaming, and finally treating with a treatment liquid. The modified copolymer contains a long-chain fluoroalkane and a quaternary ammonium salt structure, and the positively charged quaternary ammonium salt functional group can attract the negatively charged cell membrane, so that the quaternary ammonium salt is adsorbed on the bacterial surface, thus achieving a good antibacterial effect. However, this method uses an azo-based chemical foaming agent, which is not conducive to environmental protection.

[0006] CN119264399A discloses a PBAT foaming material and its preparation method. First, terephthalic acid and adipic acid are respectively blended with 1,4-butanediol to obtain PTA / BDO slurry and AA / BDO slurry, and then esterification is carried out respectively to obtain two kinds of oligomers; the two kinds of oligomers are mixed and further esterified to obtain PBAT oligomer. After the PBAT oligomer is polycondensed, pelletized and dried, PBAT particles are obtained. After vacuum drying, a plate is made and foamed. By regulating the PBAT synthesis process, changing the sequence structure and distribution of different chain segments on the PBAT molecular chain, and combining with the supercritical carbon dioxide solid-state foaming processing technology, PBAT foaming materials with different mechanical properties (strength and hardness) can be prepared to be suitable for buffer packaging materials under different packaged items and different transportation and storage environmental conditions. This method requires changing the synthesis route of PBAT, and it is necessary to prepare modified particles first, then carry out autoclave pressure foaming, and finally steam molding. The preparation method is relatively complex and not conducive to industrialization.

[0007] The traditional PBAT foaming method is to first prepare high melt strength PBAT modified particles, and then use supercritical CO 2 , N 2 and other blowing agents to carry out foaming in a foaming extruder. The foaming shape is restricted by the die head shape, and at the same time, it is necessary to additionally add CO 2 , N 2 and other blowing agents, and the preparation process is complex. Summary of the Invention

[0008] The present invention provides a PBAT alloy and its preparation method, a foamed sheet and its preparation method. The PBAT alloy includes PBAT resin, chain extender, plasticizer, primary amine compound, and basic compound. The present invention uses low molecular weight PBAT resin, which has more terminal carboxyl and terminal hydroxyl reaction groups, reacts with the added primary amine compound to generate tertiary amine compounds, which can be used as CO 2 responsive polymers to absorb carbon dioxide released by basic compounds in the system. The prepared modified particles are directly used for compression molding and foaming, and release CO 2 as a blowing agent during the heating process. The foamed sheet prepared by this method can have a foaming ratio of 15 - 25 times.

[0009] To achieve the above object, the technical solutions adopted by the present invention are as follows:

[0010] A PBAT alloy, comprising the following components in parts by weight:

[0011] PBAT resin 85 - 98 parts, preferably 80 - 90 parts,

[0012] Chain extender 0.5 - 2.5 parts, preferably 1 - 2 parts,

[0013] Plasticizer: 1 - 5 parts, preferably 2 - 3 parts,

[0014] Primary amine compound: 0.1 - 3 parts, preferably 0.5 - 2 parts,

[0015] Basic compound: 1 - 5 parts, preferably 2 - 4 parts.

[0016] The melt index of the PBAT resin of the present invention is 3 - 20 g / 10 min, and the test conditions are 190 °C and 2.16 kg, preferably 5 - 15 g / 10 min.

[0017] The weight - average molecular weight (Mw) of the PBAT resin of the present invention is 40,000 - 120,000 g / mol, preferably 50,000 - 100,000 g / mol.

[0018] The chain extender described in the present invention is one or more of polycyclic epoxy compounds, and suitable examples include but are not limited to ADR4468, ADR4370, and ADR4400 of BASF.

[0019] The plasticizer described in the present invention is one or more of tributyl citrate, epoxidized soybean oil, monoglyceride, and dibutyl adipate.

[0020] The primary amine compound described in the present invention is one or more of ethanolamine, propanolamine, and dimethylamine.

[0021] The basic compound described in the present invention is one or more of sodium bicarbonate, calcium carbonate, and sodium carbonate.

[0022] The present invention also provides a method for preparing the PBAT alloy, comprising the following steps: mixing the PBAT resin, chain extender, plasticizer, and primary amine compound, adding them into the main feeding port of a twin - screw extruder, adding the basic compound into the middle section of the extruder, then melt - extruding, cooling, pelletizing, and drying.

[0023] In the method for preparing the PBAT alloy of the present invention, the rotational speed of the twin - screw extruder is 200 - 600 revolutions per minute, and the extrusion temperature is 160 - 200 °C.

[0024] A method for preparing a foamed sheet, comprising the following steps: preparing a foamed sheet from the PBAT alloy on a steam molding device.

[0025] The temperature of the steam molding device described in the present invention is 120 - 180 °C, the pressure is 2 - 5 bar, and the molding time is 1 - 30 s.

[0026] The PBAT foamed product prepared by the present invention has an apparent density of 0.0496 - 0.083 g / cm 3 , the foaming ratio is 15 - 25 times, and the cell diameter is 50 - 300 microns.

[0027] Compared with the prior art, the present invention has the following technical advantages: The feeding sequence of the present invention is ingeniously designed. PBAT first reacts with the primary amine compound, and then absorbs CO in the system 2 , locks CO 2 in the modified particles, and then foams in a steam molding device. Compared with the traditional foaming method, there is no need to additionally add foaming agents such as CO 2 , N 2 etc. The foaming step is simpler, and the shape is not restricted by the shape of the die head of the foam extrusion machine. Specific Embodiments

[0028] The present invention will be further described below through specific embodiments. The embodiments described in the present invention are only for the illustration of the present invention and do not limit the scope of the present invention.

[0029] In each of the examples and comparative examples, the sources of the main raw materials are as shown in Table 1 below:

[0030] Table 1 Raw Materials and Sources

[0031] Raw materials Manufacturer PBAT (T16N1, molecular weight 50,000 g / mol) Self-made PBAT (T16N2, molecular weight 80,000 g / mol) Self-made PBAT (T16N3, molecular weight 100,000 g / mol) Self-made PBAT (T16N4, molecular weight 150,000 g / mol) Self-made Ethanolamine Aladdin Reagent (Shanghai) Co., Ltd. Propanolamine Aladdin Reagent (Shanghai) Co., Ltd. Dimethylamine Aladdin Reagent (Shanghai) Co., Ltd. Triethylamine Aladdin Reagent (Shanghai) Co., Ltd. Sodium bicarbonate Aladdin Reagent (Shanghai) Co., Ltd. Sodium carbonate Aladdin Reagent (Shanghai) Co., Ltd. Calcium carbonate Aladdin Reagent (Shanghai) Co., Ltd. ADR4370 BASF (China) Co., Ltd. ADR4468 BASF (China) Co., Ltd. ADR4400 BASF (China) Co., Ltd. Tributyl citrate Yangzhou Feiyang Chemical Co., Ltd. Epoxidized soybean oil Shandong Kailian Chemical Co., Ltd. Mono-glyceride Suzhou Minghua Sugar Alcohol Co., Ltd.

[0032] The performance test parameters of PBAT alloy and PBAT foam and the corresponding test methods are as shown in Table 2 below:

[0033] Table 2 Performance Test Methods

[0034]

[0035]

[0036] The processing equipment used is:

[0037] Twin-screw extruder, Coperion, model ZSK 26Mc 18, with a length-diameter ratio of 52 and a screw diameter of 26 cm;

[0038] Steam molding equipment, Dabo Precision (DPM-0404VS) from South Korea

[0039] The test equipment used is:

[0040] Gottfert melt indexer from Germany, the test conditions are 190 °C, 21.6 kg (the melt strength of the materials prepared this time is very high and cannot be measured under the conditions of 190 °C and 2.16 kg, so the test conditions are set to 190 °C, 21.6 kg);

[0041] Tester instrument foam density testing machine;

[0042] ZEISS EVO series scanning electron microscope;

[0043] Reflection infrared test equipment: Thermo Fisher S10I.

[0044] Example 1

[0045] Using the component formulations in Table 3 as raw materials and referring to the raw material dosages in Table 3, prepare the PBAT alloy according to the following method:

[0046] a. First, dry the PBAT resin in a dehumidifying dryer at 90 °C for 6 h;

[0047] b. Mix the PBAT resin T16 (melt index 8 g / 10 min), talcum powder, chain extender, plasticizer, and ethanolamine in a high-speed mixer. The dosage of ADR4468 is 0.7 wt%, set the mixing speed to 60 rpm, and the mixing time to 10 minutes. Add it to the main feeder of the twin-screw extruder, add sodium bicarbonate to the liquid feeder port in the middle section of the extruder, and then melt and extrude. The extrusion conditions are: screw speed 200 rpm, and the screw temperature is set in sections from the feeding port to the die head as: 160 °C, 165 °C, 170 °C, 175 °C, 180 °C, 185 °C, 190 °C, 190 °C, 200 °C, 200 °C, 200 °C;

[0048] c. Cool the extruded material in the extruder water tank, pelletize it, and dry it in a vacuum oven at 90 °C for 4 h to obtain the PBAT alloy; test the infrared. The two N-H stretching vibration peaks at 3220 cm -1 disappear, indicating that the primary amine reacts with PBAT, and a stretching vibration peak of the C-H of the tertiary amine appears at 1310 cm -1 to form a tertiary amine compound.

[0049] d. Add the PBAT alloy to the steam molding equipment, set the foaming temperature to 160 °C, the pressure to 2 bar, and the foaming time to 10 s.

[0050] Example 2

[0051] Using the component formulations in Table 3 as raw materials and referring to the raw material dosages in Table 3, prepare the PBAT alloy, test the infrared. The two N-H stretching vibration peaks at 3220 cm -1 disappear, indicating that the primary amine reacts with PBAT, and a stretching vibration peak of the C-H of the tertiary amine appears at 1322 cm -1 to form a tertiary amine compound.

[0052] Except for the following conditions, the other conditions refer to Example 1: The extrusion conditions of the twin-screw extruder are as follows: the screw speed is 300 rpm, and the screw temperature is set in sections from the feeding port to the die head as: 160 °C, 160 °C, 170 °C, 170 °C, 175 °C, 175 °C, 180 °C, 180 °C, 190 °C, 190 °C, 190 °C; The PBAT alloy is added to the steam molding equipment, and the foaming temperature is set to 120 °C, the pressure is 3 bar, and the foaming time is 20 s.

[0053] Example 3

[0054] Using the raw material amounts in Table 3, prepare the PBAT alloy according to the following method, and test the infrared at 3220 cm -1 The two N-H stretching vibration peaks disappear, indicating that the primary amine reacts with PBAT. At 1350 cm -1 The stretching vibration peak of the C-H of the tertiary amine appears, generating a tertiary amine compound.

[0055] Except for the following conditions, the other conditions refer to Example 1: The extrusion conditions of the twin-screw extruder are as follows: the screw speed is 400 rpm, and the screw temperature is set in sections from the feeding port to the die head as: 170 °C, 170 °C, 170 °C, 170 °C, 170 °C, 180 °C, 190 °C, 200 °C, 200 °C, 200 °C, 200 °C; The PBAT alloy is added to the steam molding equipment, and the foaming temperature is set to 180 °C, the pressure is 5 bar, and the foaming time is 30 s.

[0056] Comparative Example 1

[0057] Using the raw materials in Example 1 and preparing the PBAT extrusion foamed sheet according to the method in Example 1, the difference is only that the PBAT resin in Table 3 is a high molecular weight PBAT with a molecular weight of 150,000 g / mol. Test the infrared at 3220 cm -1 The two N-H stretching vibration peaks do not completely disappear, indicating that the reaction ability of the primary amine with the high molecular weight PBAT is weak, and at the same time, the stretching vibration peak of the C-H of the tertiary amine does not appear.

[0058] Comparative Example 2

[0059] Using the raw materials in Example 1 and preparing the PBAT extrusion foamed sheet according to the method in Example 1, the difference is only that the formulation composition in Table 3 is different, and the primary amine compound is replaced with a tertiary amine compound. Test the infrared at 3220 cm -1 The two N-H stretching vibration peaks do not completely disappear, indicating that the tertiary amine cannot react with PBAT, and the stretching vibration peak of the C-H of the tertiary amine does not appear.

[0060] Comparative Example 3

[0061] Using the raw materials in Example 1 and preparing the PBAT extrusion foamed sheet according to the method in Example 1, with the only difference being the different formulation compositions in Table 3 and without adding alkaline compounds, test the disappearance of the two N-H stretching vibration peaks at 3220 cm -1 in the infrared spectrum, indicating that the primary amine reacts with PBAT, and the stretching vibration peak of the C-H of the tertiary amine appears at 1335 cm -1 to form a tertiary amine compound.

[0062] The performance test results of the foamed sheets obtained in Examples 1-3 and Comparative Examples 1-3 are shown in Table 4.

[0063] Table 3 Raw materials and dosages (Kg) in Examples 1-3 (S1-S3) and Comparative Examples 1-3 (D1-D3)

[0064]

[0065]

[0066] Table 4 Product performance test results of Examples 1-3 (S1-S3) and Comparative Examples 1-3 (D1-D3)

[0067] Test items S1 S2 S3 D1 D2 D3 Melt index (g / 10 min) 19 15 11 30 35 39 Foaming ratio (times) 19 18 20 10 2 0 <![CDATA[Foam density (g / cm 3 )]]> 0.065 0.083 0.056 0.095 0.113 - Cell diameter (μm) 55 38 60 128-560 200-732 -

[0068] It can be seen from Comparative Example 1 and Examples 1-3 that if the molecular weight of PBAT is too large, the reaction activity of the primary amine compound with high molecular weight PBAT decreases, and it is impossible to form a tertiary amine compound, and it is impossible to effectively lock CO 2 , and the final prepared foam has a low foaming ratio and uneven cell structure. It can be seen from Comparative Example 2 and Examples 1-3 that without adding primary amine substances and only adding tertiary amine substances, it is impossible to introduce tertiary amine groups on the PBAT matrix, and it is impossible to effectively lock CO 2 , and the final prepared foam has a low foaming ratio and uneven cell structure; it can be seen from Comparative Example 3 and Examples 1-3 that without adding alkaline compounds, it is impossible to release CO 2 , the system lacks a foaming agent, and the purpose of foaming cannot be achieved. The present invention selects a low molecular weight PBAT resin, which has more terminal carboxyl and terminal hydroxyl reaction groups, reacts with the added primary amine compound to form a tertiary amine compound, which can be used as a CO 2 responsive polymer, absorbs the carbon dioxide released by sodium bicarbonate in the system, and the prepared modified particles are directly used for compression molding foaming, and release CO 2 as a foaming agent during the heating process. The foaming ratio of the foamed sheet prepared by this method can reach 15-25 times.

[0069] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the method of the present invention, several improvements and supplements can be made, and these improvements and supplements should also be regarded as the protection scope of the present invention.

Claims

1. A PBAT alloy comprising the following components in parts by weight:

2. The PBAT alloy according to claim 1, characterized in that: The weight average molecular weight of the PBAT resin is 40,000-120,000 g / mol, preferably 50,000-100,000 g / mol.

3. The PBAT alloy according to claim 1, characterized in that: The chain extender is one or more of ADR4468, ADR4370, and ADR4400.

4. The PBAT alloy according to claim 1, characterized in that: The plasticizer is one or more of tributyl citrate, epoxidized soybean oil, monoglyceride, and dibutyl adipate.

5. The PBAT alloy according to claim 1, characterized in that: The primary amine compound is one or more of ethanolamine, propanolamine and dimethylamine.

6. The PBAT alloy according to claim 1, characterized in that: The alkaline compound is one or more of sodium bicarbonate, calcium carbonate and sodium carbonate.

7. A method for preparing the PBAT alloy according to any one of claims 1 to 6, comprising the following steps: mixing PBAT resin, chain extender, plasticizer, and primary amine compound, adding the mixture to the main feed port of a twin-screw extruder, adding an alkaline compound to the middle section of the extruder, followed by melt extrusion, cooling, pelletizing, and drying.

8. A method for preparing a foamed sheet, comprising the following steps: The PBAT alloy according to any one of claims 1 to 6 is used to prepare a foamed sheet on a steam molding device.

9. The method according to claim 8, characterized in that The temperature of the steam molding equipment is 120-180°C, the pressure is 2-5 bar, and the molding time is 1-30s.

10. A foamed sheet prepared by the method according to claim 8 or 9, characterized in that: The apparent density of the foamed sheet is 0.0496-0.083 g / cm 3 The expansion ratio is 15-25 times, and the pore diameter is 50-300 microns.

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