JPS61211337A - High-viscosity aliphatic polyamide and its production - Google Patents

Abstract

PURPOSE:To facilitate the production of a high-viscosity aliphatic polyamide, by pretreating an aliphatic polyamide intermediate polymer having a content of terminal amino groups and terminal carboxyl groups of a specified value or larger by adding thereto orthophosphoric acid and water and effecting its solid phase polymerization. CONSTITUTION:An aliphatic polyamide intermediate polymer having a content (10<-3> equivalent per kg) of terminal amino groups and terminal carboxyl groups >=a value determined according to formula I (wherein RV is a relative viscosity) is prepared. This aliphatic polyamide intermediate polymer is mixed with orthophosphoric acid and water and pretreated by agitating in a pressurized inert gas. This polymer is solid-phase-polymerized at a temperature of 160 deg.C - the m.p. of the polymer in vacuum in an inert gas stream. In this way, the desired high-viscosity aliphatic polyamide containing at least 10ppm of phosphortriamide structure units of formula II and having a relative viscosity >=6 is obtained.

Description

Detailed Description of the Invention (Field of Industrial Application) This invention relates to a high viscosity aliphatic polyamide and a method for producing the same.

It is used in the field of industrial materials that require high strength, high modulus, high fatigue resistance, and high impact resistance, especially in the fields of fibers and plastic molding materials.

(Prior art) In the production of aliphatic polyamide, a method of adding phosphoric acid and a phosphorus compound is known. It has various effects such as suppressing polymer decomposition and improving dyeability, and many types of phosphorus compounds, both organic and inorganic, are used.1 The various effects mentioned above vary depending on the individual compound and the amount used. Show effectiveness. For example, when a polyamide intermediate polymer is melted and supplied to a vacuum evaporator, and is maintained in the form of a thin film, thread, or particulate within the evaporator for post-polymerization, the intermediate polymer supplied to the evaporator is 1 selected from ortho, pyro, or meta phosphoric acid, phosphorous acid, hypophosphorous acid, or esters of these acids.
A species or two or more compounds are contained in a range of 0.01 mol % or less, and - water vapor or a mixed vapor with water containing alcohols is introduced into the atmosphere of the non-force generator in the evaporator so that its partial pressure is reduced. A method for producing high viscosity polyamide in which post-polymerization is carried out while actively introducing the material so that the temperature is 2 to 200 mmHg
5-49711) is known, and this method is effective in preventing gelation of polyamide that has become highly viscous due to post-polymerization. Also.

In the production of solid homogeneous high molecular weight polyamides by heated solid phase post-condensation in the presence of an inert gas.

in the presence of (a) an organic acid selected from mono- and di-carboxylic acids as a chain stabilizer; (b) an inorganic or mineral acid as a catalyst for polyamide polymerization to form a solid polyamide;
A linear low viscosity spinnable polyamide is produced and the resulting polyamide is heated at a temperature below the melting point of the polyamide.
Process for producing polymeric polyamides by heating for a long time until the molecular weight of the product reaches maximum uniformity and a uniform final viscosity independent of residence time (see Japanese Patent Publication No. 49-2.8679)
is known, and phosphoric acid is used as the polymerization catalyst (b).

(Problem to be solved) The relative viscosity of the polyamide obtained by the above-mentioned known polyamide production method is lower than 6.0,
It does not satisfy the industrial material field that requires high viscosity.

(Means for Solving the Problems) This invention provides an aliphatic polyamide with an unprecedented high viscosity and a method for producing the same, in which orthophosphoric acid added during solid phase polymerization is bonded to the molecular chains constituting the polyamide. It is something to do.

That is, this application includes two inventions, and the first invention is that the aliphatic polyamide contains 1 Opp+m or more of a phosphoric acid triamide structural unit represented by the formula % and has a relative viscosity of 6.0 or more. The second invention is a high viscosity aliphatic polyamide characterized by an amino terminal group (AEG) and a carboxyl terminal group (CE
The amount of G) (unit: 10, 'equivalent/kg) is the formula % (where RV indicates relative viscosity). Orthophosphoric acid and water are added to the above aliphatic polyamide intermediate polymer, and the mixture is pressurized. A high viscosity aliphatic polyamide, which is pretreated by stirring in an inert gas, and then solid-phase polymerized at a temperature of 160° C. or higher and lower than the melting point of the polymer under reduced pressure or in an inert gas flow. It is a manufacturing method.

The aliphatic polyamide in this invention is the well-known nylon 6
, nylon 66, nylon 46. It is nylon 610 or the like, and further contains a copolyamide mainly composed of the constituent units of these aliphatic polyamides.

The phosphoric acid triamide structural unit represented by the above chemical formula contained in the aliphatic polyamide of the present invention is 10 ppm or more, preferably 20 to 11,000 ppm. This phosphoric acid triamide structural unit is characterized by the magnetic resonance spectrum (NMR).
) confirmed by

That is, PNMR was measured using a high-resolution NMR measuring device XL 300 (manufactured by Varian).

1.1,3,3. '3-Hexafluoroisopropanol and deuterated chloroform (CD CL,: L-oc
A sample solution dissolved in a mixed solvent with k) to a concentration of 30%,
At room temperature, the measurement was carried out using orthophosphoric acid (Oppm) as a reference substance under the conditions of a pulse width of 9 μ5 ec (45°), a repetition time of 2 seconds, and a measurement frequency of 121 MH2. stop ,
A predetermined amount of a standard substance of hexamethylphosphoramide or orthophosphoric acid was added to the aliphatic polyamide sample, and PNMR was measured, and the content of phosphoric triamide structural units was calculated from the integral ratio of each peak. can be determined.

Further, the aliphatic polyamide of this invention has a relative viscosity of 6.0.
The above value is preferably 8.0 or more, particularly 10 or more, and includes those having a relative viscosity of up to about 50, which is much higher than that of conventionally known aliphatic polyamides.

The relative viscosity was determined by dissolving the sample in reagent-grade concentrated sulfuric acid of 96.3±0.1% by weight so that the polymer concentration was 1.0 g/di.

The relative viscosity of the solution is measured using an Ostwald viscometer at a temperature of 20±0.05° C. and an ice fall time of 6 to 7 seconds.

The same viscometer was used for the measurement, and the falling time T (seconds) of 20 ml of sulfuric acid was the same as when preparing the sample solution, and the sample solution 2.
Relative viscosity (RV) from the ratio of falling time Tl (seconds) of 0 m1
is calculated using the following formula.

RV=T 凰/T.

Next, a method for producing the above-mentioned high viscosity aliphatic polyamide will be explained.

As an intermediate polymer of aliphatic polyamide, amino terminal groups (
The amount of each of AEG) and carboxyl terminal group (CEG) is greater than or equal to the value calculated by the formula 85÷(RV-1) (unit: 1.0' equivalent/kg). A
If the amount of each of EG and CEG is smaller than the numerical value according to the above formula as in the case of commercially available aliphatic polyamides, the solid phase polymerization rate and the relative viscosity obtained by the same phase polymerization will be low, and even if the polymerization time is increased, this invention The desired high viscosity cannot be achieved.

The method for obtaining the above-mentioned intermediate polymer is by melt polymerization, but during melt polymerization, viscosity stabilizers or end cappers, which are added to currently commercially available aliphatic polyamides, etc. must not be added. The relative viscosity of the intermediate polymer is preferably in the range of 2.0 to 4.0.

To measure the AEG of the above intermediate polymer, a precisely weighed sample was mixed with 50ml of phenol/ethanol mixed solvent (volume ratio 4:1).
After completely dissolving with 20 ml of water/ethanol mixture (volume ratio 3:2) and 115ON ethyl alcoholic hydrochloric acid aqueous solution (a mixture of 100 ml of 1/ION hydrochloric acid and 50 ml of ethyl alcohol, diluted to 500 ml with distilled water. A sample solution is prepared by adding 4 ml of liquid), and this sample solution is determined by conductivity titration using a 1150 N aqueous sodium hydroxide solution with a known correction factor.

To measure the CEG of an intermediate polymer, a precisely weighed sample is dissolved using 20 ml of benzyl alcohol at 175±5°C under stirring in a nitrogen gas flow to obtain a sample solution, and this sample solution is prepared with a known correction factor. It is determined by titration using a 1150N aqueous potassium hydroxide solution and phenolphthalein as an indicator.

To the above intermediate polymer, an appropriate amount of orthophosphoric acid and 0.5 to 1.0% by weight of water based on the intermediate polymer are added, preferably in a pressurized inert gas at a pressure of 1.1 to 1.5 kg/cd. The mixture is preferably stirred at a temperature of 60 to 80°C for 1 to 3 hours to uniformly diffuse orthophosphoric acid into the intermediate polymer. The high viscosity aliphatic polyamide is then prepared under the usual conditions for solid state polymerization of aliphatic polyamides, i.e. heating at temperatures above 160 DEG C. and below the melting point of the polymer for 3 to 1000 hours under reduced pressure or in a stream of inert gas. can get.

When adding or-1-phosphoric acid to the above intermediate polymer,
If water is not added, it is difficult to uniformly disperse orthophosphoric acid into the intermediate polymer, resulting in uneven solid phase polymerization, which is undesirable. Pressure is 1.1kg/aJ
If the pressure is less than 1.5 kg/cd, the diffusion of orthophosphoric acid into the intermediate polymer will be insufficient, resulting in uneven solid phase polymerization and a decrease in the polymerization rate, which is undesirable.If the pressure exceeds 1.5 kg/cd, expensive pressure-resistant equipment will be required. This is not preferable because it requires the following steps, which increases equipment production costs. Furthermore, if the stirring temperature is too high, the polyamide will thermally decompose under the influence of the water added together with orthophosphoric acid, which is not preferable. Furthermore, if the temperature during solid phase polymerization is less than 160° C., the solid phase polymerization rate will drop significantly and the viscosity of the resulting polymer will decrease, which is not preferred.

(Example) Example 1 Relative viscosity 3.55 obtained by melt polymerization without adding terminal capping agent. 50 to the intermediate polymer of nylon 6 with an AEG value of 35.4 and a CEG value of 34.1.
ppm of orthophosphoric acid and 0.50 wt of water were added, then stirred uniformly for 2 hours at 70°C under nitrogen gas pressure of 1.3 kg/cnf, and further heated to 180°C. , 0.15 anHg for 25 hours to carry out solid phase polymerization. The relative viscosity of the obtained high viscosity nylon 6 was 11.3. In addition, the PNMR measurement results are as shown in Figure 1, and there is a prominent peak due to the phosphoric acid triamide structure on the low frequency side of about 20 pp- relative to orthophosphoric acid, and the sample solution contains hexafluoride. The content of phosphoric acid triamide structure was determined by adding 20 ppm of methylphosphoramide.43
It was Ppm.

Example 2 The same nylon 6 intermediate polymer as in Example 1 was treated with 75 ppm orthophosphoric acid and 0.50% by weight of the intermediate polymer.
of water and mixed uniformly in the same manner as in Example 1, and then
The mixture was stirred at 00° C. and 0.10 nuHg for 70 hours to carry out solid phase polymerization. The relative viscosity of the obtained high-viscosity nylon 6 was 30.5, and PNMR showed a peak of the phosphoric acid triamide structure similar to that shown in Figure 1, and its content was 7.
It was 0 ppHl.

Comparative Example Relative viscosity 3.5, AEG value 28.8 obtained by adding 0.25% by weight of a 50% aqueous solution of acetic acid/n-butylamine = 1/1 (mol) and measuring the melt weight using a conventional method. ,
An intermediate polymer of nylon 6 with a CEG value of 27.5 was treated with 50 ppm orthophosphoric acid based on the intermediate polymer, and 0.
Add 1% polymerization water and heat to 160° C. without performing the same pretreatment stirring as in Example 1.

Solid phase polymerization was carried out by stirring for 25 hours under the condition of 0.15 ■Hg. The relative viscosity of the obtained nylon 6 was 5.3, much lower than that of Example 1.2 above, and PNM
The measurement results for R are as shown in FIG. 2, and no peak due to the phosphoric acid triamide structure was observed.

(Effects of the Invention) The aliphatic polyamide of the present invention has a high relative viscosity that has never been seen before, and is used for industrial materials that require high strength, high modulus, high fatigue resistance, and high impact resistance. It can be effectively used as

[Brief explanation of drawings]

Figure 1 shows "PNM" of high viscosity aliphatic polyamide according to Example.
This is a graph obtained by measuring R, and FIG. 2 is a graph obtained by measuring PNMR of an aliphatic polyamide of a comparative example. Patent Applicant Toyobo Co., Ltd. Agent Patent Attorney Takeshi Sakano Gaffe 1) Tsukasa Ryo (ppm) (1) pm) Procedural Amendment Commissioner Michibu Uga Patent Application No. 52100 of 1985 2 Name of the Invention High-viscosity aliphatic polyamide and its manufacturing method 3 Name of the person making the amendment Name (316) Toyobo Co., Ltd. 4 Agent address 2-10-5 Azuchi-cho, Higashi-ku, Osaka Date of amendment order Voluntary order 6 Target of amendment 7 Amendment Contents (1) "High viscosity" on page 3, line 9 of the specification was corrected to "high viscosity." (2) "Selection" on page 3, line 16 of the letter of specification was corrected to "selection." (3) "Said magnetic resonance" on page 6, line 6 of the specification is appropriate to "pinned magnetic resonance." (4) On page 6, line 14 of the specification, rMH2J was corrected to “rMH Engineering.” (5) On page 6, line 17 of the specification letter, "or-1-a! quasi-substance of phosphoric acid" was corrected to "standard substance such as orthophosphoric acid." (6) Page 9, line 5 of the specification, r175±5°C" was corrected to "170±5°C." (7) On page 9, line 8 of the specification letter, "potassium hydroxide" was corrected to "potassium hydroxide." (8) "Melted weight" on page 12, line 5 of the specification letter was corrected to "molten heavy gold."

Claims (1)

[Scope of Claims] [1] The aliphatic polyamide contains 10 ppm or more of a phosphoric acid triamide structural unit represented by the formula ▲ Numerical formula, chemical formula, table, etc. ▼ and has a relative viscosity of 6.0 or more. A high viscosity aliphatic polyamide characterized by: [2] The amount of amino terminal group (AEG) and carboxyl terminal group (CEG) (unit: 10^-^3 equivalent/kg) is expressed by the formula 85÷(RV-1) (where RV indicates relative viscosity). A certain aliphatic polyamide intermediate polymer is pretreated by adding orthophosphoric acid and water, stirred in a pressurized inert gas, and then heated under reduced pressure or inert at a temperature of 160°C or higher and lower than the melting point of the polymer. A method for producing a high viscosity aliphatic polyamide characterized by solid phase polymerization in a gas stream.