CN113004514A

CN113004514A - Low-hygroscopicity PA5T and synthesis method thereof

Info

Publication number: CN113004514A
Application number: CN202110406140.9A
Authority: CN
Inventors: 贺朋波; 贺鹏勇
Original assignee: Shenzhen Huaying New Material Co ltd
Current assignee: Shenzhen Huaying New Material Co ltd
Priority date: 2021-04-15
Filing date: 2021-04-15
Publication date: 2021-06-22
Anticipated expiration: 2041-04-15
Also published as: CN113004514B

Abstract

The invention provides PA5T with low hygroscopicity and a synthesis method thereof, wherein perfluoroadipic acid is introduced as a comonomer in the synthesis process of PA5T, so that a polyamide molecular chain is provided with a certain amount of fluorine-containing chain segments, the low surface energy characteristic of the low surface energy is capable of endowing PA5T with hydrophobicity, the hydrolysis resistance of PA5T is improved on the basis of reducing the hygroscopicity of PA5T, and the water absorption of the obtained PA5T material is reduced to below 1%. The hypophosphite and pyridine are used as catalysts, so that the fluorine-containing chain segment is more easily and uniformly dispersed on the PA5T molecular chain segment, and the hydrolysis resistance of PA5T is improved.

Description

Low-hygroscopicity PA5T and synthesis method thereof

Technical Field

The invention belongs to the field of synthesis of polyamide materials, and particularly relates to a high-temperature-resistant polyamide material and a synthesis method thereof.

Background

PA5T is a short carbon chain polyamide developed by Dongli corporation, and the key raw material of the polyamide is pentanediamine from a product of lysine decarboxylation, and the reaction can be obtained by utilizing biological reaction, and is a novel environment-friendly material. PA5T and PA6T have similar chemical structures, the melting point of PA5T is lower than that of PA6T, but the glass transition temperature is higher, the acid resistance and the heat retention stability are both higher than that of PA6T, other properties are not greatly different from those of PA6T, and the only defects are high amide group density and high water absorption rate.

Therefore, the obstacles to the industrialization of PA5T are mainly related to both the source of pentanediamine and the water-resistant modification.

CN102850541A describes a polyamide resin based on a pyran diacid, wherein the diamine can be pentamethylene diamine.

CN109972228A describes a preparation method of PA56, the moisture absorption rate is 1.2-1.6%

CN111518510A describes that the introduction of dihydric alcohol containing side hydrocarbon group during the synthesis of polyamide improves the performances of high temperature water washing resistance, solvent resistance and hydrolysis resistance.

The water-resistant modification method of PA5T has very few known methods at present and is a technical difficulty in the field.

Disclosure of Invention

The invention aims to provide PA5T with low hygroscopicity and a synthesis method thereof, wherein perfluoroadipic acid is introduced as a comonomer in the synthesis process of PA5T, hypophosphite and pyridine are used as catalysts to synthesize a PA5T material containing a fluorine chain segment, and the hygroscopicity of PA5T is reduced.

In order to achieve the purpose, the invention provides PA5T with low hygroscopicity, which comprises the following raw materials:

(A) terephthalic acid (TPA)

(B) Aliphatic diacids

(C) Perfluoroadipic acid

(D) Pentanediamine

(E) Polymerization catalyst

Wherein the ratio of the sum of the mole numbers of (A) terephthalic acid, (B) aliphatic diacid and (C) perfluoroadipic acid to (D) pentanediamine is 1 (1-1.1), preferably 1 (1-1.05), more preferably 1 (1-1.01), and still more preferably 1: 1.

In a preferred embodiment, the ratio of the mole number sum of (A) terephthalic acid to (A) terephthalic acid, (B) aliphatic diacid and (C) perfluoroadipic acid is (1-9): 10, including the following ratios: 1:10, 2:10, 3:10, 4:10, 5:10, 6:10, 7:10, 8:10, 9: 10.

In a preferred embodiment, the ratio of the (B) aliphatic diacid to the sum of the mole numbers of (A) terephthalic acid, (B) aliphatic diacid and (C) perfluoroadipic acid is (1-9): 10, including the following ratios: 1:10, 2:10, 3:10, 4:10, 5:10, 6:10, 7:10, 8:10, 9: 10.

In a preferred embodiment, the ratio of the (C) perfluoroadipic acid to the sum of the moles of (A) terephthalic acid, (B) aliphatic diacid and (C) perfluoroadipic acid is (1-3): 10, including the following ratios: 1:10, 2:10, 3: 10.

In a preferred embodiment, the (B) aliphatic diacid is one or more of glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid.

In a preferred embodiment, the (E) polymerization catalyst comprises hypophosphite and pyridine.

The hypophosphite is one or more of sodium hypophosphite, potassium hypophosphite, magnesium hypophosphite and calcium hypophosphite.

In a preferred embodiment, the molar ratio of the hypophosphite to the pyridine is 100 (5-20), preferably 100 (10-15), and more preferably 100: 10.

In a preferred embodiment, the ratio of the (E) polymerization catalyst to the sum of the mass of (A) terephthalic acid, (B) aliphatic diacid, (C) perfluoroadipic acid and (D) pentanediamine is 0.03 to 0.1%.

The invention provides a synthetic method of low-hygroscopicity PA5T, which comprises the following steps: (1) putting terephthalic acid, aliphatic diacid, perfluoro adipic acid and pentanediamine into a polymerization reaction kettle, adding a catalyst and water, sealing and stirring, replacing with non-reactive gas, and setting the gas pressure to be 10-100 kPa. (2) And (3) heating the temperature in the kettle to 90-110 ℃, and preserving the heat for 1-3 hours until the raw materials are completely salified. (3) And continuously heating the polymerization reaction kettle, releasing water vapor when the pressure in the kettle reaches a set value, and maintaining the pressure for 1-3 hours. And then continuously heating to 280-320 ℃, keeping the pressure constant for 1-3 hours, and discharging after aeration to obtain the low-hygroscopicity PA 5T.

In a preferred embodiment, the non-reactive gas in step (1) is one or more of nitrogen, carbon dioxide, helium, neon and argon.

In a preferred embodiment, the air pressure in the step (1) is preferably 10 to 50kPa, and more preferably 50 kPa.

In a preferred embodiment, the temperature in the kettle in step (2) is raised to 90-100 ℃, preferably 95 ℃.

In a preferred embodiment, the temperature keeping time in the step (2) is 1-2 hours, preferably 2 hours.

In a preferred embodiment, the pressure set value in the step (3) is 1 to 3MPa, preferably 2 to 3MPa, and more preferably 3 MPa.

In a preferred embodiment, the pressure maintaining time in the step (3) is 1 to 2 hours, preferably 1 hour.

In a preferred embodiment, the temperature for further raising the temperature in the step (3) is 280 to 310 ℃, preferably 290 to 310 ℃, and further preferably 310 ℃.

In a preferred embodiment, the constant pressure time in step (3) is 1-2 hours, preferably 1 hour.

Compared with the prior art, the invention has the following beneficial effects.

(1) According to the invention, perfluoroadipic acid is introduced in the synthesis process of PA5T, so that a certain amount of fluorine-containing chain segments are carried on a polyamide molecular chain, the low surface energy characteristic of the perfluoroadipic acid can endow PA5T with hydrophobicity, and the hydrolysis resistance of PA5T is improved on the basis of reducing the hygroscopicity of PA 5T. By introducing perfluoroadipic acid, the water absorption of PA5T can be reduced to 1% or less.

(2) The preparation method disclosed by the invention is simple in process, adopts a one-pot polymerization method, does not need to spatially separate the steps of salt, prepolymerization and solid-phase tackifying, can complete all the steps by adopting one polymerization kettle, and is convenient to produce.

Detailed Description

The following embodiments of the present invention are further described in conjunction with the detailed description, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein.

Before the present embodiments are further described, it is to be understood that the scope of the present invention includes, but is not limited to, the following specific embodiments. In general, the terminology used in the examples herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention. The test methods in the following examples, in which specific conditions are not specified, are generally carried out under conventional conditions or conditions recommended by the respective manufacturers.

When numerical ranges are given in the examples, it is understood that both endpoints of each of the numerical ranges and any value therebetween can be selected unless the invention otherwise indicated. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition to the specific methods, devices, and materials used in the examples, any methods, devices, and materials similar or equivalent to those described in the examples may be used in the practice of the invention in addition to the specific methods, devices, and materials used in the examples, in keeping with the knowledge of one skilled in the art and with the description of the invention.

Preparation example 1

Preparing a catalyst: 17.2g of sodium hypophosphite and 1.58g of pyridine are mixed in a test tube, and the mixing is promoted in ultrasound to obtain catalyst suspension slurry.

Example 1

(1) Putting 0.5mol of terephthalic acid, 0.3mol of adipic acid, 0.2mol of perfluorinated adipic acid and 1mol of pentamethylene diamine into a polymerization reaction kettle, adding 0.14g of catalyst suspension slurry, uniformly mixing, injecting 100mL of deionized water, sealing the polymerization kettle, starting stirring at the stirring speed of 100rpm, and adding N₂The gas was replaced three times, and the pressure in the autoclave was set to 50 kPa.

And (3) raising the temperature in the kettle to 110 ℃ and keeping the temperature for 1 hour until the diacid and the pentanediamine are respectively and completely salified.

And continuously heating the polymerization reaction kettle, opening the pressure release valve to release the generated water vapor when the pressure in the kettle reaches 3MPa, and keeping the pressure in the kettle at constant pressure for 1 hour. Then continuously heating to 310 ℃ at the speed of 5 ℃/min, keeping the pressure constant for 1 hour, and filling N into the kettle₂And discharging to obtain the low-hygroscopicity PA 5T.

Measuring the moisture absorption rate of the low moisture absorption PA5T, wherein the moisture absorption rate is measured according to the following conditions: at 23 deg.C, relative humidity 50%, equilibrate for 24 hours.

Example 2

Example 1 was repeated, except that the molar amounts of terephthalic acid, adipic acid and perfluoroadipic acid were set to 0.5mol, 0.2mol and 0.3mol based on example 1, and the other conditions were not changed.

Comparative example 1

Example 1 was repeated, except that the molar amounts of terephthalic acid, adipic acid and perfluoroadipic acid were set to 0.5mol, 0.5mol and 0mol based on example 1, and the other conditions were not changed.

Comparative example 2

Example 1 was repeated, except that the molar amounts of terephthalic acid, adipic acid and perfluoroadipic acid were set to 0.5mol, 0mol and 0.5mol based on example 1, and the other conditions were not changed.

The moisture absorption rates of PA5T obtained in examples 1 to 2 and comparative examples 1 to 2 are shown in the following tables.

TABLE 1

	Moisture absorption Rate (%)
		Example 1	0.13
Example 2	0.08
		Comparative example 1	1.41
Comparative example 2	—

The moisture absorption rate of PA5T can be adjusted by adjusting the proportion of perfluoroadipic acid to total diacid, but the amount of perfluoroadipic acid cannot be increased without limitation. This is because perfluoroadipic acid contains a high amount of fluorine, and if the amount of fluorine is too high, it will cause severe phase separation with other dibasic acids and diamines, and both of them will not form salts sufficiently, resulting in difficulty in polymerization.

Example 3

Example 1 was repeated, except that adipic acid was replaced by sebacic acid on the basis of example 1, and the other conditions were unchanged.

Example 4

Example 1 was repeated, except that adipic acid was replaced by dodecanedioic acid on the basis of example 1, and the other conditions were unchanged.

Example 5

Example 1 was repeated, except that the molar amounts of terephthalic acid, adipic acid and perfluoroadipic acid were set to 0.3mol, 0.5mol and 0.2mol based on example 1, and the other conditions were not changed.

The moisture absorption rates of PA5T obtained in examples 3 to 5 are shown in the following tables.

TABLE 2

	Moisture absorption Rate (%)
		Example 3	0.11
Example 4	0.10
		Example 5	0.11

Example 6

Example 1 was repeated, except that sodium hypophosphite was replaced by potassium hypophosphite on the basis of example 1, and the other conditions were not changed.

Comparative example 3

Example 1 was repeated, except that the catalyst suspension slurry was replaced with equal mass of sodium hypophosphite on the basis of example 1, and the other conditions were not changed.

Comparative example 4

Example 1 was repeated, except that pyridine was replaced with furan on the basis of example 1, and other conditions were unchanged.

Comparative example 5

Example 1 was repeated, except that pyridine was replaced with piperidine on the basis of example 1, and other conditions were not changed.

The moisture absorption rates of PA5T obtained in example 6 and comparative examples 3 to 5 are shown in the following table.

TABLE 3

	Moisture absorption Rate (%)
		Example 6	0.14
Comparative example 3	1.21
		Comparative example 4	1.24
Comparative example 5	1.27

As can be seen from Table 3, the addition of pyridine made it easier for the catalyst to catalyze the polymerization of the amide, replacing it with another type of aromatic hydrocarbon, such as furan, or a non-aromatic heterocyclic compound, such as piperidine, which gave a moisture absorption of PA5T similar to that of comparative example 3 without pyridine, i.e. perfluoroadipic acid did not or only very little participate in the polymerization without the catalyst with pyridine.

All documents referred to herein are incorporated by reference into this application as if each were individually incorporated by reference. Furthermore, it should be understood that various changes and modifications of the present invention can be made by those skilled in the art after reading the above teachings of the present invention, and these equivalents also fall within the scope of the present invention as defined by the appended claims.

Claims

1. The PA5T with low hygroscopicity is characterized by comprising the following raw materials:

(A) terephthalic acid (TPA)

(B) Aliphatic diacids

(C) Perfluoroadipic acid

(D) Pentanediamine

(E) A polymerization catalyst.

2. The PA5T having low hygroscopicity as claimed in claim 1, wherein said (B) aliphatic diacid is one or more of glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid.

3. The low moisture absorption PA5T of claim 1 wherein (E) a polymerization catalyst comprises a hypophosphite and pyridine.

4. The low hygroscopicity PA5T as claimed in claim 3, wherein said hypophosphite is one or more of sodium hypophosphite, potassium hypophosphite, magnesium hypophosphite, and calcium hypophosphite.

5. The PA5T with low hygroscopicity of claim 3, wherein the molar ratio of the hypophosphite to the pyridine is 100 (5-20), preferably 100 (10-15), and more preferably 100: 10.

6. The PA5T with low hygroscopicity as claimed in claim 1, wherein the ratio of the mass of the polymerization catalyst (E) to the mass of the sum of the mass of the polymerization catalyst (A) terephthalic acid, (B) aliphatic diacid, (C) perfluoroadipic acid and (D) pentanediamine is 0.03 to 0.1 percent.

7. The low hygroscopic PA5T according to claim 1, wherein the ratio of the molar sum of (A) terephthalic acid and (A) terephthalic acid, (B) aliphatic diacid and (C) perfluoroadipic acid is (1-9: 10; the ratio of the aliphatic diacid (B) to the sum of the mole numbers of terephthalic acid (A), aliphatic diacid (B) and perfluorinated adipic acid (C) is (1-9): 10; the ratio of the (C) perfluoroadipic acid to the sum of the mole numbers of (A) terephthalic acid, (B) aliphatic diacid and (C) perfluoroadipic acid is (1-3): 10.

8. The PA5T with low hygroscopicity as claimed in any one of claims 1 to 7, wherein the moisture absorption rate of PA5T is 1% or less.

9. The method for synthesizing PA5T having a low hygroscopicity as claimed in any one of claims 1 to 8, wherein (1) terephthalic acid, aliphatic dicarboxylic acid, perfluoroadipic acid and pentanediamine are charged into a polymerization reactor, a polymerization catalyst and water are charged into the reactor, the reactor is sealed and stirred, and the mixture is replaced with a non-reactive gas under a pressure of 10 to 100 kPa; (2) heating the temperature in the kettle to 90-110 ℃ and preserving the heat for 1-3 hours until the raw materials are completely salified; (3) and continuously heating the polymerization reaction kettle, releasing water vapor when the pressure in the polymerization reaction kettle reaches a set value, maintaining the pressure for 1-3 hours, continuously heating to 280-320 ℃, keeping the pressure constant for 1-3 hours, inflating and discharging to obtain the low-hygroscopicity PA 5T.

10. A catalyst composition for the synthesis of PA5T with low hygroscopicity, comprising a hypophosphite and pyridine.