阅读说明：本技术 一种聚羟基乙酸（pga）增塑剂及其制备方法 (Polyglycolic acid (PGA) plasticizer and preparation method thereof ) 是由 李兴伟 楚喆 楚军政 于 2021-09-22 设计创作，主要内容包括：本发明公开了一种聚羟基乙酸(PGA)增塑剂及其制备方法,属于塑料助剂领域。该产品由乙酸或乙酸酐,羟基乙酸,单/双甘油脂肪酸酯等原料,经过缩聚反应,酯化反应,精制等过程得到乙酰寡聚羟基乙酸单双脂肪酸甘油酯。通过改变其酰化度和聚合度以及脂肪酸的碳链分布,使其溶度参数和PGA相近,提高乙酰寡聚羟基乙酸单双脂肪酸甘油酯和PGA的相容性,将其应用于PGA制品中,能提高其断裂伸长率,改善柔软性和脆性,有效提高PGA制品的品质和稳定性。其为含有以下化学式的混合物：。(The invention discloses a polyglycolic acid (PGA) plasticizer and a preparation method thereof, belonging to the field of plastic additives. The product is prepared from acetic acid or acetic anhydride, glycolic acid, mono/diglycerol fatty acid ester and other raw materials through polycondensation reaction, esterification reaction, refining and other processes. The acylation degree, the polymerization degree and the carbon chain distribution of the fatty acid are changed to enable the solubility parameter of the derivative to be close to that of the PGA, so that the compatibility of the acetyl oligomeric glycolic acid mono-di-fatty acid glyceride and the PGA is improved, and the derivative can be applied to PGA products to improve the breaking elongation, improve the flexibility and the brittleness and effectively improve the quality and the stability of the PGA products. It is a mixture containing the following chemical formula:)

1. The plasticizer is characterized by comprising a mixture with the following chemical formula structures,

n is one or more of the above numerical ranges.

2. A method for preparing an acetylated oligoglycolic acid mono-diglycerol fatty acid ester plasticizer according to claim 1, comprising the steps of:

(1) putting glycolic acid into a reaction kettle, heating while feeding, then adding a catalyst A, continuously heating to perform prepolymerization reaction, after the prepolymerization reaction is finished, heating until no water is evaporated, keeping the system at constant temperature, vacuumizing, controlling the pressure to continue the reaction, controlling the average polymerization degree to reach 2-5, and stopping the polycondensation reaction when the molecular weight reaches 130-320 to obtain oligomeric glycolic acid;

(2) putting the mono-diglycerol fatty acid ester and the prepared oligomeric glycolic acid into a reaction kettle according to the material proportion, adding a catalyst B, heating under vacuum to perform esterification reaction, and judging the end point according to the acid value of less than 2mgKOH/g for later use;

(3) adding glacial acetic acid or acetic anhydride into the step (2) for esterification reaction, distilling out excessive acetic acid or acetic anhydride after the reaction is ended, washing with water until the acid value is less than 2mgKOH/g and the hydroxyl value is less than 5mgKOH/g, cooling, decoloring, washing with water, drying and packaging to obtain a product;

the catalyst A is sodium titanate, tetramethylguanidine or stannous octoate; the catalyst B is sodium hydroxide, potassium hydroxide or calcium hydroxide;

the mono-diglycerol fatty acid ester is at least one of mono-diglycerol caprylate, mono-diglycerol caprate, mono-diglycerol laurate, mono-diglycerol palmitate, mono-diglycerol stearate and diglycerol stearate.

Technical Field

The invention relates to an acetyl oligomeric glycolic acid mono-diglycerol fatty acid ester plasticizer and a preparation method thereof, belonging to the field of plastic additives.

Background

Polyglycolic acid (PGA), also called polyglycolide, is the simplest linear aliphatic polyester, is also an aliphatic polyester polymer material with the highest degradation speed, has good biodegradability, biocompatibility and excellent gas isolation, and can be applied to the aspects of medical materials, oil and gas exploitation, agriculture and forestry production, packaging materials, disposable environmental protection products and the like. The material has too short repeating units, weak internal movement capability of molecules and too high radical density, so that the material has high melting point, high hardness and no good processability.

The method commonly adopted for modifying polyglycolic acid at present is physical blending. The Japanese Urethane company mixes PGA and polyethylene terephthalate, and prepares a degradable polyester bottle with high transparency and good gas barrier property by stretching treatment under the action of a heat stabilizer, and the degradable polyester bottle is applied to food packaging materials at present, so that the use of non-degradable plastics is greatly reduced. PGA and xanthan gum, hydroxypropyl guar gum and other renewable polysaccharides are blended by China petrochemical company Limited to prepare the high-strength degradable temporary plugging agent for fracturing.

In view of this, the development of a plasticizer suitable for polyglycolic acid to lower the melting point of the product and improve the brittleness and softness thereof is an effective way to facilitate the mass use of PGA materials.

Disclosure of Invention

The invention aims to provide an acetylated oligo-glycolic acid mono-diglycerol fatty acid ester plasticizer, which is characterized in that polyglycolic acid is embedded into the structure of acetylated mono-diglycerol fatty acid ester, so that the solubility parameter of the acetylated mono-diglycerol fatty acid ester plasticizer is close to that of PGA, the compatibility and the elongation at break of the acetylated oligo-glycolic acid mono-diglycerol fatty acid ester plasticizer with the PGA are improved, and the flexibility and the brittleness of the PGA are improved. Another object is to provide a process for the preparation thereof.

To achieve the object of the present invention, the plasticizer of the present invention is a mixture containing the following molecular structures:

the preparation method of the acetohydroxyacetic acid mono-diglycerol fatty acid ester plasticizer comprises the following steps:

(1) putting the measured glycolic acid into a reaction kettle, and heating while putting; and then adding a catalyst A, continuing to heat for a prepolymerization reaction, after the prepolymerization reaction is finished, heating until no water is evaporated, keeping the system at a constant temperature, vacuumizing, controlling the pressure to continue the reaction, controlling the average polymerization degree to reach 2-5, and stopping the polycondensation reaction when the molecular weight reaches 130-320 to obtain the oligomeric glycolic acid. (average molecular weight and degree of polymerization were calculated specifically based on the amount of water discharged).

(2) Putting the mono-diglycerol fatty acid ester and the prepared oligomeric glycolic acid into a reaction kettle according to the material proportion, adding a catalyst B, heating under vacuum to carry out esterification reaction, and judging the end point according to the acid value of less than 2mgKOH/g for later use.

(3) Adding glacial acetic acid or acetic anhydride into the step II to carry out esterification reaction, distilling out excessive acetic acid or acetic anhydride after the reaction is ended, washing with water until the acid value is less than 2mgKOH/g and the hydroxyl value is less than 5mgKOH/g, cooling after the reaction is ended, decoloring, washing with water, drying and packaging to obtain the product.

The mono-diglycerol fatty acid ester is at least one of mono-diglycerol caprylic acid ester, mono-diglycerol capric acid ester, mono-diglycerol lauric acid ester, mono-diglycerol palmitic acid ester, mono-diglycerol stearic acid ester.

The catalyst A is sodium titanate, tetramethylguanidine or stannous octoate; the catalyst B is sodium hydroxide or potassium hydroxide or calcium hydroxide.

The monoglyceride is a product of glycerin with one hydroxyl group esterified with fatty acid, and also has two free hydroxyl groups (monoglyceride); the diglycerol fatty acid ester is a product of esterification of two hydroxyl groups of glycerin with fatty acid, and also has a free hydroxyl group (diglyceride). The mono-diglycerol fatty acid ester and the diglycerol fatty acid ester are a mixture of the mono-diglycerol fatty acid ester and the diglycerol fatty acid ester.

The invention has the advantages that: by changing the polar groups of the mono-diglycerol fatty acid ester and the diglycerol fatty acid ester, the acylation degree, the polymerization degree and the carbon chain distribution of the fatty acid are changed, so that the solubility parameter is more similar to that of the PGA, and the compatibility of the acetyl oligomeric glycolic acid mono-diglycerol fatty acid ester and the PGA is improved. The acetyl oligomeric glycolic acid mono-diglycerol fatty acid ester is applied to the PGA product, so that the elongation at break of the product is improved, the mobility and the brittleness of the product are improved, the flexibility of the product is enhanced, the performance is more stable, and the quality of the product is effectively improved.

Detailed Description

To better illustrate the invention, the following examples are given:

example 1

Putting 450Kg of glycolic acid into a reaction kettle, heating while putting, and maintaining the temperature at 70-85 ℃; then adding sodium titanate, continuously raising the temperature to 110-115 ℃, starting prepolymerization reaction, after prepolymerization for 1 hour, raising the temperature to 130-140 ℃, after anhydrous is evaporated, keeping the temperature of the system and starting vacuumizing, keeping the pressure at-0.092-0.098 MPa, after the anhydrous is evaporated, keeping the state and continuously reacting for 1 hour, wherein the water yield is 20Kg, and the average polymerization degree is controlled to 2, thus obtaining 430Kg of the product polyglycolic acid.

350Kg of mono-diglycerol stearate and 430Kg of polyglycolic acid prepared above are put into a reaction kettle, 1Kg of sodium hydroxide is added, the temperature is gradually raised to 165-170 ℃ under vacuum, and then the reaction is carried out for 4 hours under heat preservation, the water yield is about 40Kg, and the reaction is stopped when the acid value is less than 2mgKOH/g, thus obtaining about 740Kg of intermediate.

Injecting about 300Kg of acetic anhydride into the intermediate prepared in the last step, carrying out reflux reaction at the temperature of 135-140 ℃ for 5-6h, distilling out acetic acid which does not participate in the reaction until the acid value is less than 10mgKOH/g, adding 100Kg of water into the acetic anhydride, washing with water, standing, carrying out layering to obtain residual acetic anhydride, repeatedly washing with water until the acid value is 1mgKOH/g, and then, drying after washing with water, wherein the water content is 0.5%, and packaging to obtain the product, namely, the acetyl-dimeric hydroxyl acetic acid mono-diglycerol stearate AOGS.

Example 2

Putting 450Kg of glycolic acid into a reaction kettle, heating while putting, and maintaining the temperature at 70-85 ℃; and then adding stannous octoate, continuously raising the temperature to 115 ℃ for 110-.

Putting 270Kg of mono-diglycerol laurate, diglycerol laurate and 400Kg of polylactic acid prepared above into a reaction kettle, adding 1Kg of potassium hydroxide, gradually raising the temperature to 175-180 ℃ under vacuum, keeping the temperature and reacting for 4h, wherein the water yield is 35-40Kg, and the reaction is stopped when the acid value is less than 2mgKOH/g, thus obtaining an intermediate.

Injecting about 220Kg of acetic anhydride into the intermediate prepared in the last step, carrying out reflux reaction at the temperature of 135-140 ℃ for 5-6h, distilling off acetic anhydride which does not participate in the reaction until the acid value is less than 10mgKOH/g, adding 100Kg of water into the intermediate, carrying out water washing to remove residual acetic acid, repeatedly carrying out water washing until the acid value is 1mgKOH/g, drying after the hydroxyl value is less than 5mgKOH/g, and packaging to obtain the product of acetylated triglycerol laurate AOLS.

Example 3

Putting 450Kg of glycolic acid into a reaction kettle, heating while putting, and maintaining the temperature at 70-85 ℃; then adding tetramethylguanidine, continuing to raise the temperature to 115 ℃ for 110-.

Then 300Kg of a mixture of mono-and diglycerol fatty acid esters (wherein mono-and diglycerol caprylate, mono-and diglycerol laurate, mono-and diglycerol palmitate, and mono-and diglycerol stearate respectively account for 25%) is added, 2.2Kg of calcium hydroxide is added, the temperature is gradually raised to 175 ℃ under vacuum, the reaction is carried out for 8 hours, the water yield is 30-40Kg, and the reaction is stopped when the acid value is less than 2mgKOH/g, thus obtaining an intermediate.

Injecting about 200Kg of glacial acetic acid into the intermediate prepared in the last step, carrying out reflux reaction at the temperature of 135-140 ℃ for 5-6h, distilling out acetic acid which does not participate in the reaction until the acid value is less than 10mgKOH/g, adding 100Kg of water into the intermediate, carrying out water washing to remove residual acetic acid, repeatedly carrying out water washing until the acid value is less than 1mgKOH/g and the hydroxyl value is less than 5mgKOH/g, drying, and packaging to obtain the product, namely the acetylated triglycerol monoacetate AOMM, wherein the water content is 0.5%.

Application example

Respectively adding 15 parts of acetyl oligomeric glycolic acid mono-and diglycerol fatty acid ester plasticizers (AOGS, AOLS and AOMM) prepared in the example, 84 parts of PGA resin, 0.5 part of nucleating agent, 0.2 part of antioxidant and 0.3 part of dispersing agent into a high-speed mixer to mix for 40 min; then sending the mixture into a double-screw machine for extrusion granulation; drying the granules in a 60 ℃ air-blast oven for 12h, adding the granules into a single-screw extruder, and carrying out extrusion blow molding, wherein the temperature of the single screw is 200-230 ℃, the rotating speed is 20-40rpm, and the length-diameter ratio L/D = 25/1. The obtained modified material has the following application properties:

aging test conditions: and preparing a standard sample strip, aging at 35 ℃ and 90% RH for 30 days, and testing the tensile property of the material at normal temperature according to the GB/T1040-2006 standard method. The tensile rate was set at 10mm/min, and the same sample was tested for at least 6 bars and the average test results were as follows:

experiments show that the acetyl oligo-glycolic acid mono-diglycerol fatty acid ester plasticizer has good plasticizing and modifying effects on PGA, can effectively improve the tensile strength and the elongation at break, and has the best AOMM effect.