WO2022134381A1

WO2022134381A1 - High-crystalline modified pga material and preparation method therefor

Info

Publication number: WO2022134381A1
Application number: PCT/CN2021/086168
Authority: WO
Inventors: 邢青涛; 黎坛; 王俊峰; 赵洁
Original assignee: 海南赛诺实业有限公司
Priority date: 2020-12-24
Filing date: 2021-04-09
Publication date: 2022-06-30
Also published as: CN112679926A; CN112679926B

Abstract

The present invention provides a high-crystalline modified PGA material and a preparation method therefor. The modified PGA material is prepared from the following raw materials in parts by weight: 70-80 parts of a polyglycolic acid resin, 5-15 parts of a filler, 4-25 parts of a plasticizer, and 0.5-1 part of a nucleating agent; the plasticizer is a mixture of polyvinyl alcohol and glycerol that have a mass ratio of 1:1.8-2.3, the molecular weight of polyvinyl alcohol being 300-500 g/mol, and the degree of alcoholysis being greater than or equal to 98%; the nucleating agent is selected from one or more of talcum powder, inositol, and sebacic acid dimethylphenyl hydrazide; and the filler is selected from one or more of nano montmorillonite, nano calcium carbonate, and edible starch. By modifying the polyglycolic acid resin using the plasticizer, the nucleating agent, and the filler of said types, the modified PGA material has relatively high crystalline performance and can be used for preparing a high-heat-resistance product. The Vicat softening temperature is 205-210°C; the semi-crystallization time is 5-15 s; and the relative crystallinity is 45-47%.

Description

A kind of highly crystalline modified PGA material and preparation method thereof

This application claims the priority of the Chinese patent application filed on December 24, 2020 with the application number 202011548290.5 and the title of the invention is "a highly crystalline modified PGA material and its preparation method", the entire contents of which are Incorporated herein by reference.

technical field

The invention belongs to PGA materials, and particularly relates to a highly crystalline modified PGA material and a preparation method thereof.

Background technique

PGA (polyglycolic acid), also known as polyglycolide, has the shortest repeating unit in its molecular structure and has the fastest degradation rate among aliphatic polyester materials. At the same time, its low molecular weight product is an ideal complete microbial degradation inducer.

However, due to the high melting point of the PGA material itself, the melting point exceeds 200 ° C, but its glass transition temperature is low, which makes its heat resistance temperature further improved. It is well known that the heat resistance temperature of polymer materials is restricted by the glass transition temperature and the melting point.

Therefore, improving the crystallinity and crystallization speed of PGA materials provides conditions for the preparation of high heat-resistant products.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a modified PGA material with high crystallinity and a preparation method thereof. The modified PGA material has high crystallinity.

The invention provides a kind of modified PGA material with high crystallinity, which is prepared by including the following raw materials in parts by weight:

70-80 parts of polyglycolic acid resin, 5-15 parts of filler, 4-25 parts of plasticizer and 0.5-1 part of nucleating agent;

The plasticizer is a mixture of polyvinyl alcohol and glycerol with a mass ratio of 1:1.8-2.3, the molecular weight of the polyvinyl alcohol is 300-500 g/mol, and the alcoholysis degree is ≥98%;

The nucleating agent is selected from one or more of talc, inositol and dimethylbenzene sebacate; the filler is selected from one or more of nano-montmorillonite, nano-calcium carbonate and food grade starch. kind.

Preferably, the polyglycolic acid resin has a weight average molecular weight of 100,000 to 500,000 g/mol, and a melting point of 220 to 230°C.

Preferably, the plasticizer is prepared according to the following method:

After mixing polyvinyl alcohol and glycerin according to a mass ratio of 1:1.8-2.3, drying at 75-85° C. for 5.5-6.5 hours, and mixing for 25-35 minutes to obtain a plasticizer.

The present invention provides a preparation method of the modified PGA material described in the above technical solution, comprising the following steps:

The polyglycolic acid resin, filler, plasticizer and nucleating agent are mixed, extruded and granulated, and dried to obtain the modified PGA material.

Preferably, in the extrusion granulation process, the temperature of the feeding section is 120-140°C; the temperature of the mixing section is 210-230°C; and the temperature of the extrusion section is 220-240°C.

Preferably, the extrusion granulation adopts the method of water-stretching; the temperature of the water is 75°C to 80°C.

Preferably, the drying temperature is 75-85° C., and the drying time is 1.5-2.5 h.

The invention provides a modified PGA material with high crystallinity, which is prepared by including the following raw materials in parts by weight: 70-80 parts of polyglycolic acid resin, 5-15 parts of filler, and 4-25 parts of plasticizer and 0.5 to 1 part of a nucleating agent; the plasticizer is a mixture of polyvinyl alcohol and glycerol with a mass ratio of 1:1.8 to 2.3, the molecular weight of the polyvinyl alcohol is 300 to 500 g/mol, and the alcoholysis degree is greater than or equal to 98 %; the nucleating agent is selected from one or more of talc, inositol and dimethylbenzene sebacate; the filler is selected from one or more of nano montmorillonite, nano calcium carbonate and food grade starch or more. In the present invention, the plasticizer, nucleating agent and filler of the above components are used to modify the polyglycolic acid resin, so that the modified PGA material has higher crystallinity, that is, has a higher Vicat softening point, and can be used as a high Preparation of heat-resistant articles. The experimental results show that the Vicat softening temperature is 205℃～210℃; the half crystallization time is 5～15s; the relative crystallinity is 45～47%.

Detailed ways

In the present invention, the plasticizer, nucleating agent and filler of the above components are used to modify the polyglycolic acid resin, so that the modified PGA material has higher crystallinity, that is, has a higher Vicat softening point, and can be used as a high Preparation of heat-resistant articles.

In parts by weight, the raw materials for the preparation of the highly crystalline modified PGA material provided by the present invention include 70-80 parts of polyglycolic acid resin; the weight-average molecular weight of the polyglycolic acid resin is 100,000-500,000 g/mol , the melting point is 220 ~ 230 ℃. In a specific embodiment, the amount of the polyglycolic acid resin used is 80 parts; the weight average molecular weight of the polyglycolic acid resin is 200,000 g/mol or 100,000 g/mol, and the melting point is 230°C or 220°C. Molecular weight can ensure the mechanical properties and shelf life of PGA materials. PGA with too high molecular weight is not conducive to cost control and difficult to process. PGA with too low molecular weight has insufficient mechanical properties and short shelf life, so it cannot be applied on a large scale.

The preparation raw materials of the highly crystalline modified PGA material provided by the present invention include 5 to 15 parts of filler; in a specific example, the amount of the filler is 15 parts; the filler is selected from nano-montmorillonite, nano-calcium carbonate and edible one or more of the starch grades. Due to their small size and specific surface area, nano-montmorillonite and nano-calcium carbonate act as a part of inorganic nucleating agents and compatibilizers, inserting between PGA macromolecular segments in an intercalation manner to promote PGA crystallization The spherulite growth in the process plays a positive role in improving the crystallinity and the crystallization speed. The addition of food-grade starch as a compatibilizer and a filler that reduces costs makes related products more promising in the market under the premise of improving product performance.

The raw material for the preparation of the highly crystalline modified PGA material provided by the present invention includes 4-25 parts of plasticizer; the plasticizer is a mixture of polyvinyl alcohol and glycerol with a mass ratio of 1:1.8-2.3, and the polymer The molecular weight of vinyl alcohol is 300～500g/mol, and the alcoholysis degree is ≥98%. In a specific embodiment, the amount of the plasticizer is 9 parts or 4.5 parts. The molecular weight of polyvinyl alcohol is 500 g/mol, and the alcoholysis degree is 99%; or the molecular weight of polyvinyl alcohol is 500 g/mol, and the alcoholysis degree is 95%. The plasticizer is a mixture of polyvinyl alcohol and glycerol in a mass ratio of 1:2 or a mixture of polyvinyl alcohol and glycerin in a mass ratio of 1:2.2. The polyvinyl alcohol as a plasticizer needs to control the molecular weight and alcoholysis degree. The low molecular weight cannot play a plasticizing effect, and the effect of the nucleating agent is not obvious; The nucleation movement is unfavorable.

The preparation raw material of the highly crystalline modified PGA material provided by the present invention includes 0.5-1 part of a nucleating agent; the nucleating agent is selected from one or more of talc, inositol and dimethyl toluzide sebacate , more preferably selected from inositol and/or dimethyl sebacic acid dimethyl hydrazide. In a specific embodiment, the amount of the nucleating agent is 0.5 part or 1 part.

In the present invention, the plasticizer is preferably prepared according to the following method:

The glycerol is preferably technical grade glycerol. The mass ratio of the polyvinyl alcohol and glycerol is 1:1.8-2.3, preferably 1:2. In a specific embodiment, polyvinyl alcohol and glycerol are mixed according to a mass ratio of 1:2, dried at 80° C. for 6 hours, and mixed for 30 minutes.

The preparation raw materials of the highly crystalline modified PGA material provided by the present invention include 0.5-1 part of a nucleating agent; the nucleating agent is selected from one or more of talc, inositol and dimethyl toluzide sebacate . The above types of nucleating agents can be combined and compounded through different requirements for heat resistance temperature and crystallinity, which can promote the heterogeneous nucleation of PGA resin, thereby accelerating the nucleation rate and crystal growth rate, and improving the crystallinity of PGA. Thereby increasing the Vicat softening point of the material and enhancing the heat resistance of the product.

The present invention provides a method for preparing the highly crystalline modified PGA material described in the technical solution, comprising the following steps:

In the present invention, the temperature of the feeding section in the extrusion granulation process is preferably 120 to 140 °C, more preferably 130 °C; the temperature of the mixing section is preferably 210 to 230 °C, more preferably 220 °C; the temperature of the extrusion section is Preferably it is 220-240 degreeC, More preferably, it is 230 degreeC. The invention adopts a twin-screw extruder for extrusion granulation, and the length-diameter ratio of the extruder is at least 1:75.

In the present invention, the extrusion granulation adopts the method of water-stretching; the temperature of the water is 75°C to 80°C.

In the present invention, the drying temperature is preferably 75-85°C, more preferably 80°C; the drying time is preferably 1.5-2.5h, more preferably 2h.

In the present invention, the PGA material with high crystallinity is prepared by adopting the above-mentioned raw material combined with the process control, the Vicat softening temperature of the modified PGA material is significantly increased, and the modified PGA material can be used for the preparation of high heat-resistant products.

The invention adopts DSC (differential calorimetry scanner) to study the crystallization behavior of the polymer, uses pure indium to correct the baseline under the condition of 10° C./min, and the test is carried out under the protection of nitrogen gas of 50ml/min. About 8 mg of the sample was put into a sealed aluminum crucible, and the temperature was raised from room temperature to 200 °C at a heating rate of 50 °C/min, and kept for 5 min to eliminate thermal history. Then cool down to the preset crystallization temperature TC at a cooling rate of 50°C/min, keep at TC for a period of time until the DSC curve returns to the baseline, and finally heat the sample to 200°C at a heating rate of 10°C/min, and record the DSC curve .

The isothermal process curve records the isothermal crystallization exothermic process of the PLA blend, and the subsequent secondary heating curve records the melting endothermic process of the crystalline part of the blend.

In order to observe the effect of isothermal heat treatment in the melt on the crystallization behavior of the samples, DSC was used to measure the crystallinity of the tensile bars after quenching and treatment at 134 °C, respectively. min. The crystallinity of the sample can be calculated from the relevant parameters obtained in the above-mentioned heating DSC curve:

The exothermic enthalpy when the α' crystal form of PLA is further developed into the α crystal form with more perfect crystal structure when the melting point is near, ω _PLA is the mass fraction of PLA in the sample,

is the ideal melting enthalpy of 100% crystalline PLA and its value is 93.6 J/g.

From this, the relative crystallinity and half-crystallization time of the material can be calculated.

According to GB/T 1633-2000, the thermal deformation and Vicat softening point temperature tester was used to test the VST of the samples after heat treatment. The sample was cut into a size of 10 × 10 × 4 mm, the heating medium was phenyl methyl silicone oil, the heating rate was 120 °C/h, the load was 1 kg, and the temperature when the probe penetrated the sample 1 mm thick was VST. The error of the two results is less than 2°C, and the average value is recorded.

The present invention adopts the method of GB/T 19277.1 to test the degradation performance of the modified PGA material.

In order to further illustrate the present invention, a highly crystalline modified PGA material provided by the present invention and its preparation method are described in detail below with reference to the examples, but they should not be construed as limiting the protection scope of the present invention.

Example 1

According to the weight ratio of raw materials: 0.5 part of nucleating agent, 80 parts of polyglycolic acid resin (PGA), 15 parts of filler, 4.5 parts of plasticizer; the nucleating agent is inositol; the filler is edible starch; the The weight-average molecular weight of the polyglycolic acid resin is 200,000 g/mol, and the melting point is 220 °C; the plasticizer is to mix polyvinyl alcohol and glycerol in a mass ratio of 1:2, and then dry at 75 °C for 6 hours, and then mix 30min to obtain a plasticizer, the molecular weight of the polyvinyl alcohol is 500g/mol, and the alcoholysis degree is 99%;

First mix the above raw materials with a high-speed mixer for 1 hour, and then put it into the twin-screw extruder for granulation; the length-diameter ratio of the twin-screw extruder should be at least 1:75, and the temperature of the feeding section should be kept at about 130 °C, and the temperature of the mixing section is 220 °C, the temperature of the extrusion section is kept at about 230 °C; the granulation is carried out by means of water-stretching, and the temperature of the water tank needs to be controlled at 75 °C to 80 °C; the finished masterbatch needs to be dried at 80 °C for 2 hours. Packed in aluminum foil, evacuated and stored in a dry environment to obtain a modified PGA material with high crystallinity.

The performance parameter test results of the modified PGA material prepared in Example 1 are shown in Table 1:

Table 1 The performance parameters of the modified PGA material prepared in Example 1 and the raw material PGA

It can be seen from Table 1 that the crystallinity and crystallization speed of the modified PGA material have been significantly improved, and its heat-resistant temperature (Vicat softening temperature) has also increased from 170 °C to more than 200 °C. At the same time, the control of semi-crystallization time and crystallization temperature can achieve precise control of the process in the later stage, and prepare high heat-resistant products.

Example 2

According to the weight ratio of raw materials: 1 part of nucleating agent, 75 parts of polyglycolic acid resin (PGA), 15 parts of filler, 9 parts of plasticizer; the nucleating agent is dimethylbenzene sebacate; the filler is Nano-montmorillonite; the weight-average molecular weight of the polyglycolic acid resin is 100,000 g/mol, and the melting point is 230° C.; After drying at 80°C for 6 hours, mixing for 25 minutes to obtain a plasticizer, the molecular weight of the polyvinyl alcohol is 500 g/mol, and the alcoholysis degree is 95%;

The performance parameter test results of the modified PGA material prepared in Example 2 are shown in Table 1:

Table 2 The performance parameters of the modified PGA material prepared in Example 2 and the raw material PGA

It can be seen from Table 2 that the crystallinity and crystallization speed of the modified PGA material have been significantly improved, and its heat-resistant temperature (Vicat softening temperature) has also increased from 170 °C to more than 200 °C. At the same time, the control of semi-crystallization time and crystallization temperature can achieve precise control of the process in the later stage, and prepare high heat-resistant products.

Comparative example

According to the weight ratio of raw materials: 0.5 part of nucleating agent, 80 parts of polyglycolic acid (PGA), 15 parts of filler, 4.5 parts of plasticizer; the nucleating agent is sorbitol; the filler is talc; the Plasticizer dibutyl phthalate; the weight-average molecular weight of the polyglycolic acid resin is 200,000 g/mol, and the melting point is 220°C;

The performance parameter test results of the modified PGA materials prepared by the comparative example are shown in Table 1:

Table 3 Performance parameters of modified PGA materials and raw PGA prepared by comparative example

It can be seen from Table 3 that the crystallinity and crystallization speed of the modified PGA material of the comparative example have not been significantly improved, and its heat-resistant temperature (Vicat softening temperature) has not changed much, so high heat-resistant products cannot be prepared.

It can be seen from the above examples that the present invention provides a highly crystalline modified PGA material, which is prepared by including the following raw materials in parts by weight: 70-80 parts of polyglycolic acid resin, 5-15 parts of filler, 4 parts of ～25 parts of plasticizer and 0.5～1 part of nucleating agent; the plasticizer is a mixture of polyvinyl alcohol and glycerol with a mass ratio of 1:1.8～2.3, and the molecular weight of the polyvinyl alcohol is 300～500g/mol , the degree of alcoholysis ≥ 98%; the nucleating agent is selected from one or more of talc, inositol and sebacic acid dimethyl hydrazide; the filler is selected from nano-montmorillonite, nano-calcium carbonate and edible one or more of the starch grades. In the present invention, the above-mentioned plasticizers, nucleating agents and fillers are used to modify the polyglycolic acid resin, so that the modified PGA material has higher crystallinity, that is, has a higher Vicat softening point, and can be used as a high-resistance PGA material. Preparation of thermal products. The experimental results show that the Vicat softening temperature is 205℃～210℃; the half crystallization time is 5～15s; the relative crystallinity is 45～47%.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims

A highly crystalline modified PGA material, characterized in that, in parts by weight, prepared by comprising the following raw materials:

70-80 parts of polyglycolic acid resin, 5-15 parts of filler, 4-25 parts of plasticizer and 0.5-1 part of nucleating agent;

The plasticizer is a mixture of polyvinyl alcohol and glycerol with a mass ratio of 1:1.8-2.3, the molecular weight of the polyvinyl alcohol is 300-500 g/mol, and the alcoholysis degree is ≥98%;

The nucleating agent is selected from one or more of talc, inositol and dimethylbenzene sebacate; the filler is selected from one or more of nano-montmorillonite, nano-calcium carbonate and food grade starch. kind.
The modified PGA material according to claim 1, wherein the polyglycolic acid resin has a weight average molecular weight of 100,000 to 500,000 g/mol, and a melting point of 220 to 230°C.
The modified PGA material according to claim 1, wherein the plasticizer is obtained by the following method:

After mixing polyvinyl alcohol and glycerin according to a mass ratio of 1:1.8-2.3, drying at 75-85° C. for 5.5-6.5 hours, and mixing for 25-35 minutes to obtain a plasticizer.
A preparation method of the modified PGA material described in any one of claims 1 to 3, comprising the following steps:

The polyglycolic acid resin, filler, plasticizer and nucleating agent are mixed, extruded and granulated, and dried to obtain the modified PGA material.
The preparation method according to claim 4, characterized in that, in the extrusion granulation process, the temperature of the feeding section is 120-140 °C; the temperature of the mixing section is 210-230 °C; the temperature of the extrusion section is 220-240 °C °C.
The preparation method according to claim 4, characterized in that, the extrusion granulation adopts the method of water-stretching; and the temperature of the water is 75°C to 80°C.
The preparation method according to claim 4, wherein the drying temperature is 75-85°C, and the drying time is 1.5-2.5h.