JPH0610259B2 - High molecular weight acrylamide unit-containing β-alanine copolymer and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a β-alanine copolymer containing a high molecular weight acrylamide unit and a method for producing the same. More specifically, the present invention is useful for applications such as polymer additives, molding materials such as films and sheets, paints, adhesives, coating agents, printing inks, paper processing agents, soil conditioners, and fiber treatment agents. TECHNICAL FIELD The present invention relates to a β-alanine copolymer having a high degree of polymerization and having a high degree of thermal stability and containing an acrylamide unit, and a method for producing the same.

Prior Art Regarding the method for producing poly-β-alanine by hydrogen transfer polymerization of acrylamide, since it was first reported in 1957, "Journal of American Chemical Society (J. Am. Chem. Soc.)" Volume 79, page 3760 (1957
Years)], and many reports have been made.

The hydrogen transfer polymerization of acrylamide usually uses 1/10 to 1/100 mol of alkali metal alcoholate per 1 mol of acrylamide as a catalyst and N-phenyl as a radical polymerization inhibitor in a solvent such as toluene, xylene, chlorobenzene or pyridine. It is carried out by heating to a temperature of 80 to 140 ° C in the presence of -β-naphthylamine and the like.

However, the polymer obtained by such a method includes not only a hydrogen transfer polymer but also a vinyl polymer of acrylamide [Polymer Chemistry, Volume 20, p. 364 (1963)]. Therefore, in the usual hydrogen transfer polymerization of acrylamide, A polymer composed of is produced, and in this copolymer, the ratio of the hydrogen transfer polymerization portion and the vinyl polymerization portion is
It depends on the type and amount of catalyst used, reaction conditions, and the like.

For example, when the amount of catalyst for acrylamide decreases,
The proportion of hydrogen transfer type tends to be low, and the proportion of vinyl polymerization type tends to increase. It is also known that when the amount of the catalyst is 1/100 mol or less with respect to 1 mol of acrylamide, the polymerization reaction is difficult to proceed and the yield of the polymer is reduced. For example, using sodium butoxide as a catalyst,
It has been reported that the polymer yield is 0 to 5% when the amount of the catalyst is reacted at 1/200 mol with respect to 1 mol of acrylamide ["Priten Chemical Society, Japan," Vol. 33, p. 906]. (1960)].

In addition, a method of producing poly-β-alanine by polymerizing acrylamide in an organic solvent using about 1/30 mol of calcium ethylate per 1 mol of acrylamide as a polymerization catalyst has been proposed (special feature JP-B-38-26791), the polymer obtained by this method has a reduced viscosity of 1.
When it is 0 or less, it is a low polymer.

Further, the present inventors have previously found and proposed a method for producing poly-β-alanine by hydrogen transfer polymerization of acrylamide using a calcium alcoholate having 3 or more carbon atoms as a catalyst (Japanese Patent Application Laid-Open No. S60-18753). 59-213722 publication). However, in this method, poly-β-alanine having a high degree of polymerization can be obtained, but the amount of calcium alcoholate used as a catalyst is as large as 0.02 mol or more per mol of acrylamide. It was not always a satisfactory method in that a large amount of alkaline earth metal (calcium) remained and the amount of primary amide groups in the polymer was small.

Thus, in the conventional method, when polymerizing acrylamide to produce a poly-β-alanine polymer,
As described above, the catalyst is added to 1 mol of acrylamide,
Since it is used in an extremely large amount of about 1/10 to 1/100 mol, a large amount of alkali metal or alkaline earth metal derived from the catalyst remains in the obtained product, and these metals bind to the polymer. Alternatively, since it is coordinated, it cannot be removed by a normal washing operation, and it is difficult to completely remove the metal by a special method such as ion exchange treatment.

Problems to be Solved by the Invention An object of the present invention is to contain a high molecular weight acrylamide unit containing β having a high primary amide group content and a low metal content and giving excellent thermal stability when blended with a polyacetal. -To provide an alanine copolymer.

Means for Solving the Problems The present inventors have conducted extensive studies to develop a β-alanine copolymer having a high primary amide group content and a high molecular weight acrylamide unit. Alkaline earth metal alcoholate is used as a raw material, the raw material acrylamide and the solvent are highly purified, and by devising the polymerization operation, the polymerization reaction is smoothly performed even when the amount of the catalyst used is much smaller than in the conventional method. It was found that the polymer progressed and had excellent physical properties, and the present invention was completed based on this finding.

That is, the present invention has the formula A structural unit (I) represented by Of the structural unit (II), the content of the primary amide group in the structural unit (II) is 4.9 to 7.0 mmol per 1 g of the polymer, and the reduced viscosity (η _sp / c) is at least It was made for the purpose of providing a β-alanine copolymer containing a high molecular weight acrylamide unit, which is characterized in that it is 2 dl / g.

This β-alanine copolymer containing a high molecular weight acrylamide unit contains, for example, acrylamide in an amount of 1 / mol.
It can be produced by using / 5000 to 1/20000 mol of an alkaline earth metal alcoholate catalyst and polymerizing in a reaction system free from impurities.

Hereinafter, the present invention will be described in detail.

The β-alanine copolymer containing an acrylamide unit of the present invention has a main structural unit of the formula: And the formula unit A polymer having a structural unit represented by the formula (II) and the content of the primary amide group in the structural unit represented by the formula (II) is in the range of 4.9 to 7.0 mmol per 1 g of the polymer. Is. Further, the acrylamide unit-containing β-alanine copolymer of the present invention has a wide range of molecular weights from formic acid soluble to formic acid insoluble, and its reduced viscosity (η _sp / c) is 2 dl / g or more. As described above, the acrylamide unit-containing β-alanine copolymer of the present invention is significantly different from the conventional poly-β-alanine in that the content of primary amide groups is large and the reduced viscosity is as large as 2 or more. That is the point.

In the present invention, an alkaline earth metal alcoholate is used as a catalyst. Examples of the alkaline earth metal alcoholate include calcium methylate, calcium ethylate, calcium-n-propylate, strontium ethylate, barium ethylate and magnesium ethylate. These catalysts are 1/5000 to 1/20 for 1 mol of acrylamide.
It is necessary to use within the range of 000.

Generally, when the amount of catalyst for acrylamide decreases,
The hydrogen transfer polymer in the polymer is reduced, and as a result, the content ratio of the primary amide group is increased. On the other hand, when the amount of the catalyst for acrylamide increases, the structural unit (I) formed by hydrogen transfer polymerization Of the structural unit (II) having a primary amide group with an increased content of The content ratio of is reduced. Therefore, in order to obtain a acrylamide unit-containing β-alanine copolymer having a primary amide group content of 4.9 to 7.0 mmol per gram thereof, the catalyst amount is 1 / mole of acrylamide.
It is necessary to select in the range of 5000 to 1/20000. On the other hand, when the amount of the catalyst exceeds 1/5000 mol, when the obtained polymer is used as a heat stabilizer for polyacetal resin, the heat stabilizing effect is not sufficiently exhibited. On the other hand, when this amount is less than 1 / 20,000 mol, the polymerization reaction is difficult to proceed, the yield is reduced, and the content of primary amide groups in the resulting polymer is too large. When used as a heat stabilizer for a polyacetal resin, the heat stabilizing effect is not sufficiently exhibited.

The polymerization reaction in the present invention may be carried out in the absence of a solvent or in the presence of a solvent. As the solvent, for example, xylene, toluene, o-dichlorobenzene or the like can be used.

In this polymerization reaction, it is preferable to minimize water, oxygen and other impurities in the reaction system. Therefore, it is advantageous to remove water in the solvent or the raw material acrylamide in advance. The water content in the solvent is
For example, it can be removed by using a dehydrating agent or by azeotropic distillation. On the other hand, the water content in acrylamide is, for example, 40
In acrylamide held at a temperature in the range of ~ 60 ° C,
It can be removed by introducing dehumidified air for about 10 to 24 hours or by keeping acrylamide at a temperature in the range of 40 to 60 ° C. for about 5 to 10 hours under a vacuum of 40 to 100 Torr.

Since this polymerization reaction is preferably carried out in the absence of oxygen, it is usually carried out in an atmosphere of an inert gas such as nitrogen or argon using acrylamide and a solvent from which oxygen has been removed. To remove acrylamide and oxygen in the solvent, for example, a method of depressurizing and then substituting with nitrogen or purging with nitrogen gas is used.

Furthermore, if impurities are present in the polymerization system, the desired β-alanine unit-containing polyacrylamide cannot be obtained.
It is necessary to remove impurities from the system as much as possible. The catalyst used is preferably stored under a nitrogen gas atmosphere in order to prevent deterioration due to moisture or oxygen.
In the present invention, it is preferable not to use the radical polymerization inhibitor used in the conventional production of poly-β-alanine polymer, such as naphthylamine. This is because the polymerization inhibitor poisons the catalyst in the same manner as the impurities, and inhibits the formation of the desired polymer.

In the present invention, the reaction temperature is usually selected in the range of 70 to 150 ° C, preferably 80 to 140 ° C. If the reaction temperature is less than 70 ° C, the reaction rate is too slow to be practical.

The polymerization reaction is performed, for example, by thoroughly dispersing a predetermined amount of a catalyst in a dehydrated and purified solvent, adding dehydrated and purified acrylamide, and heating in an inert gas atmosphere. As the polymerization method, a batch-type solution polymerization method, a batch-type bulk polymerization method, a continuous-type solution polymerization method, a continuous-type bulk polymerization method, or the like can be used.

The acrylamide unit-containing β-alanine copolymer thus obtained is generally a mixture of polymers having different degrees of polymerization. That is, the polymerization product may be a formic acid-soluble acrylamide unit-containing β-alanine copolymer [hereinafter referred to as poly-β-alanine polymer (A)], or this product and a formic acid-insoluble acrylamide depending on the polymerization conditions. Unit-containing β-alanine copolymer [hereinafter, poly-β
-Referred to as alanine polymer (B)]. Generally, when the polymerization temperature is low, only the poly-β-alanine polymer (A) is produced, but when the polymerization temperature is higher than a certain temperature, the poly-β-alanine polymer (B) is poly-β-.
It is produced together with the alanine polymer (A).

The temperature at which the poly-β-alanine polymer (B) begins to be produced depends on the amount of the alkaline earth metal alcoholate catalyst used, but in general, the poly-β-alanine polymer has a polymerization temperature of 95 to 140 ° C. The ratio of the polymer (B) increases as the temperature rises after the formation of (A) begins. For example, in solution polymerization, the poly-β-alanine polymer (B) is hardly produced at a reaction temperature of 90 ° C, but is produced at a ratio of about 1% at 120 ° C. On the other hand, in bulk polymerization,
For example, an alkaline earth metal catalyst is used in 1/10000 mol per mol of acrylamide, and the temperature is 100 ° C. for 1.5 hours.
Polymerization by stepwise raising at 10 ° C for 1.5 hours, 120 ° C for 1.5 hours, and 140 ° C for 1.5 hours gives a poly-β-alanine polymer.
(B) produces 3 to 5%.

When only poly-β-alanine polymer (A) is produced,
This may be separated from the reaction system. On the other hand, when poly-β-alanine polymers (A) and (B) are produced, the poly-β-alanine polymers (A) and (B) can be separated from the polymerization mixture by utilizing the difference in solubility. .

Furthermore, the poly-β-alanine polymer (A) can be converted to (B) by heating the polymerization product at a temperature of 140 to 180 ° C. For example, when the heat treatment time is 0.5 to 3 hours, the poly-β-alanine polymer (A) is 40 to 50%.
Converted to degree (B). Therefore, the polymerization product is thus heat-treated to convert the poly-β-alanine polymer (A) therein to (B), and then the poly-β-alanine polymer (B) is separated. May be.

As a method for separating the polymerization reaction product from the reaction-terminated liquid, for example, in the case of solution polymerization, the solvent is removed by means such as filtration, and then the acrylamide in the product is washed with an appropriate solvent such as acetone or methanol. Then, the method of removing can be used.

Furthermore, in order to separate the poly-β-alanine polymer (A) and (B), for example, a mixture of these is added to a solvent in which only the poly-β-alanine polymer (A) is dissolved, and filtration, etc. The poly-β-alanine polymer (B) is isolated by the means of, while the poly-β-alanine polymer (A) is prepared by pouring the filtrate into a solvent such as methanol or acetone, After A) is precipitated, it can be recovered by means such as filtration. Examples of the solvent that dissolves only the poly-β-alanine polymer (A) include water and formic acid.

The poly-β-alanine polymers (A) and (B) each contain the structural units (I) and (II) as a main structural unit, and contain a primary amide group. The content is in the range of 4.9 to 7.0 mmol per 1 g of polymer.
The reduced viscosity of the poly-β-alanine polymer (A) is 1
It is in the range of 2 to 15 dl / g under the measurement conditions of a weight% formic acid solution and a temperature of 35 ° C. Further in the polymer obtained in the present invention,
The weight ratio of the poly-β-alanine polymer (A) and (B) is usually
It is in the range of 20:80 to 100: 0.

The chemical structure of the β-alanine copolymer containing an acrylamide unit of the present invention can be confirmed by, for example, infrared absorption spectrum, NMR spectrum and differential scanning calorimetry (DSC). FIG. 1 shows the formic acid-soluble poly-β-of the present invention.
The infrared absorption spectrum of one example of an alanine polymer (A) is shown. ^{3290cm -1, 1535cm -1, 1108cm -1} , secondary amide group at 972 cm ^-1 Has the characteristic absorption of 3355cm ^-1 , 3190cm ^-1 , 1658cm ^-1 , 16
Primary amide group at 17 cm ^-1 There is a characteristic absorption of. From these results, in the acrylamide unit-containing β-alanine copolymer of the present invention, the secondary amide group And primary amide group It turns out that exists.

In addition, Table 1 shows β-containing the acrylamide unit of the present invention.
The DSC analysis result of an alanine copolymer and the DSC analysis result of known poly-β-alanine and polyacrylamide are shown for comparison.

From the above results, β-containing acrylamide unit of the present invention
Alanine copolymer is not just a mixture of poly-β-alanine and polyacrylamide It can be seen that the copolymer has a structural unit of.

FIG. 2 shows the NMR spectrum of the formic acid-soluble poly-β-alanine polymer. This NMR spectrum and the above IR
From the spectrum, the β-alanine unit-containing polyacrylamide of the present invention is It was confirmed to be a random copolymer having and as constituent units.

The acrylamide unit-containing β-alanine copolymer of the present invention contains a primary amide group in the range of 4.9 to 7.0 mmol per 1 g of the polymer.

The acrylamide unit-containing β-alanine copolymer of the present invention has the structural unit (I) And building units (II) And having, for example, poly-β consisting of the structural unit (I) only
-Alanine and polyacrylamide consisting only of the structural unit (II) are mixed so that the ratio of the structural units (I) and (II) is the same as that of the acrylamide unit-containing β-alanine copolymer of the present invention. It has physical properties different from those described above and exhibits excellent effects in various applications.

As described above, the acrylamide unit-containing β-alanine copolymer of the present invention contains a structural unit (II) having a primary amide group and a structural unit (I) having a secondary amide group, Since the structural unit (I) has one hydrogen bond with respect to three carbon atoms, it has a strong hydrogen bonding force and a large intermolecular bonding force. Further, since it contains the structural unit (II) having a primary amide group, it is hydrophilic and has a strong hydrogen bonding force.

Further, the acrylamide unit-containing β-alanine copolymer of the present invention, as described above, is soluble in formic acid, has a reduced viscosity (η _sp / c) of 2 to 15 dl / g, and is insoluble in formic acid. Contains, the formic acid-soluble poly-β-alanine polymer (A) is also soluble in water,
It can be used for various purposes as an aqueous solution. When the reduced viscosity of the poly-β-alanine polymer (A) is less than 2 dl / g, the mechanical strength and the adhesive force are lowered, and thus it is difficult to mold it into a film or a sheet. If the viscosity exceeds 15 dl / g, the solubility in water will be significantly reduced. This reduced viscosity can be measured by the method described below.

Further, the formic acid-insoluble poly-β-alanine polymer of the present invention
Although (B) cannot be used as an aqueous solution, it is extremely useful as a heat stabilizer for polyacetal resin, for example. This poly-β-alanine polymer (B) has a higher molecular weight than the poly-β-alanine polymer (A), and two molecules of primary amide groups react with each other to form an imide group. It is presumed to include those having a structure crosslinked between them.

Since the acrylamide unit-containing β-alanine copolymer of the present invention has the characteristics as described above, in addition to the use as the polymer additive, for example, molding materials such as films and sheets, paints, adhesives, coatings. It is useful as an agent, a printing ink, a paper processing agent, a soil improving agent, a fiber treating agent, and the like, and is particularly suitable as a heat stabilizer for a polyacetal resin.

The acrylamide unit-containing β-alanine copolymer of the present invention can be used as a formaldehyde scavenger generated in a trace amount from a phenol resin, a urea resin, a melamine resin or the like produced using formaldehyde. The addition to the above resin is the β-containing acrylamide unit of the present invention.
-Dry blend alanine copolymer powder from 0.1 to 10
Water may be added at a weight percentage, or water may be evaporated after adding the aqueous solution.

The above poly-β-alanine polymer (A) is useful as an adhesive for paper aluminum foil and the like. In this case, the poly-β-alanine polymer (A) may be dissolved in water and the aqueous solution may be coated on paper, aluminum foil or the like.

Next, the poly-β-alanine polymer (A) has excellent performance as a soil conditioner. That is, as a soil structure suitable for the growth of crops, generally, an appropriate balance of air permeability, water retention and drainage is required. Sand has good air permeability and drainage, but poor water retention, while clay has good water retention, but poor air permeability and drainage. Breathability,
A well-developed aggregate structure is desirable as a soil with well-balanced water retention and drainage properties. High molecular polysaccharides and phenolic compounds are known as aggregating agents for soil,
These have the drawback that it takes a long time for soil ecology to develop the aggregate effect. In order to eliminate such drawbacks, nonionic materials such as polyvinyl alcohol,
Anionic polymers such as polyacrylic acid and cationic polymer compounds such as polyethyleneimine have been investigated,
These polymer-based agglomerating agents have drawbacks such as a weak agglomeration effect and poor sustainability of the effect.

On the other hand, the poly-β-alanine polymer (A) has extremely strong adsorptivity with soil and has excellent sustainability of its effect, and therefore, by using the polymer as a soil conditioner. , Can be improved to a soil suitable for growing crops. Further, as another use of the soil improver, by applying the polymer of the present invention to the soil of a playground, a baseball field, or a golf course, it is possible to significantly improve the drainage property of the soil at the time of rainfall, and the inconvenience of a water pool. Is released.

Poly-β-alanine polymers are commonly used for such applications.
It is preferable to apply a 1 to 10 wt% aqueous solution of (A) at a rate of about 40 liters per 10 acres.

EFFECTS OF THE INVENTION The acrylamide unit-containing β-alanine copolymer of the present invention has a high degree of polymerization such that the reduced viscosity is 2.0 or more, so that a molded article having excellent mechanical properties, such as a film or a sheet, can be prepared. it can. Further, since the amount of the catalyst used is extremely small compared to the conventional method, the amount of metal contained in the obtained polymer is about 0.5% by weight or more in the conventional method, while 0.1 to 0.02% by weight. The degree is very small, and therefore, when it is used as a heat stabilizer of, for example, a polyacetal resin, a remarkable effect is exerted.

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The physical properties of polymers and compositions in Examples and Comparative Examples were measured and evaluated by the following methods.

(1) Reduced viscosity (η _sp / c) 5 g of a polymer is put in 100 ml of formic acid and stirred at room temperature for 2 hours to dissolve. Then, the solution is filtered under reduced pressure to obtain a formic acid solution.
500 ml of methanol is added to this formic acid solution to precipitate a formic acid solution, and the precipitate is filtered off, and then dried under reduced pressure at 80 ° C. for 10 hours in a vacuum dryer.

The sample thus obtained is dissolved in formic acid having a purity of 99% or more and then passed through a 200 mesh Tyler sieve to prepare a solution having a sample concentration of 1 g / dl. For this solution,
Measure the reduced viscosity at a temperature of 35 ° C. using an Ostwald viscometer. The reduced viscosity η _sp / c (dl / g) is calculated by the following formula.

η _sp / c (dl / g) = (t / t ₀ −1) / c where t is the number of seconds (seconds) of the sample solution falling, and t ₀ is the number of seconds (seconds) of the formic acid falling.

(2) Quantification of primary amide group In a flask equipped with a stirrer, 0.71 g of the sample polymer and 50 ml of 40 wt% potassium hydroxide aqueous solution are added, and the mixture is heated at 105 to 110 ° C for 20 minutes while stirring to give the primary amide. The group is hydrolyzed to ammonia. Then, the contents of the flask at 50 ℃
After cooling to below, 100 ml of methanol was added, ammonia was distilled out together with methanol, and the distillate was adjusted to 0.
Absorb with 1N aqueous sulfuric acid solution (V _o ml). Methyl red is used as an indicator for this absorption liquid, and neutralization titration is performed with a 0.1 N sodium hydroxide aqueous solution. This titer is Vml
And The primary amide group is calculated by the following calculation formula.

Primary amide group (mmol / g) = 0.1408 (V ₀ -V) (3) Thermal stability test (weight reduction rate) The thermal stability of the polymer is that when heated in a nitrogen stream at 250 ° C for 15 minutes. It is evaluated by the weight reduction rate. Approximately 50 mg of sample polymer
Thermogravimetric analyzer [Daini Seikosha, SSC-560GH, TG / DT
A] in a nitrogen stream.

(4) Residence Coloring A 1 ounce injection molding machine was used to heat the sample in a cylinder at 230 ° C. and retain it for 20 minutes, and the color rank of the molded test piece is represented by the following symbol.

(5) Adhesion test A polymer solution is coated on a glass plate and the solvent is evaporated to remove the polymer film. The adhesion of the polymer film to the glass plate is evaluated by the following method.
That is, a 1 mm x 1 mm keratinous cut is made in the film until it reaches the glass plate with a cutter knife. Next, attach a cellophane tape with a width of 15 mm to the film, and then peel it off by hand. At this time, the adhesive strength is evaluated by the number of crevices of the film peeled off with the tape.

Example 1 In a reactor 2 equipped with a stirrer, xylene 1.6 was put, and 0.178 g of calcium propylate (1 / 10,000 mol to 1 mol of acrylamide) was added as a catalyst, and after well dispersing in a solvent, 800 g of acrylamide was added and reacted at 90 ° C. for 4 hours while stirring in a nitrogen stream. After completion of the reaction, the solvent xylene was removed, the solid was crushed, washed with acetone and dried. Yield 769g
(Yield 96.1%). When the product was analyzed by infrared absorption spectrum, secondary amide groups were found at 3290, 1638, 1535, 1108 and 972 cm ^-1 . It has characteristic absorption of 3355, 3190, 1658, 1617 cm ^-1 and primary amide group It was confirmed that there was characteristic absorption of (Fig. 1).

The measurement conditions of the infrared absorption spectrum are as follows.

Equipment: JIR-100 FT-IR manufactured by JEOL Ltd. Measurement method: KBr method Further, ¹³ C-NMR of the dried product was measured (second).
Figure). The attribution of each peak is shown below.

The ¹³ C-NMR measurement conditions are as follows.

Equipment: JEM-GX270 type manufactured by JEOL Ltd. Observation frequency: 67.94MHz Observation width: 20000Hz Pulse width: 5.8μS Repetition time: 5.0SEC Integration number: 1000 times Measurement mode: TOSS method Structure by infrared absorption spectrum and NMR spectrum As a result of the analysis, the product was the structural unit (I). Was confirmed to be a random copolymer composed of

The content of the primary amide group is 5.5 per 1 g of the polymer.
mmol and the reduced viscosity was 2.3 dl / g. The product decomposes at about 330 ° C and the calcium content in the polymer is 5
It was 3 ppm.

This polymer was dissolved in hot water to prepare an aqueous solution, cast on a Teflon plate, and dried in an air oven at 120 ° C to form a film having a thickness of about 1 mm. Thus, the polymer has film forming properties.

Examples 2 to 3 and Comparative Examples 1 and 2 Using the reaction apparatus used in Example 1, the amount of acrylamide, the amount of solvent, and the type of solvent were the same as in Example 1, and the type of catalyst, the catalyst and acrylamide were used. Molar ratio, reaction temperature,
The reaction time was changed as shown in Table 2 to carry out.

Table 2 shows the reduced viscosity, the content of primary amide groups, and the yield of the obtained polymer. This polymer has IR and NMR
As a result of structural analysis by spectrum, structural unit (I) And building units (II) Was confirmed to be a random copolymer composed of

Example 4 In Example 1, after heating at 90 ° C. for 4 hours, further 120 ° C.
The reaction was carried out under the same conditions as in Example 1 except that the reaction was carried out by heating for 4 hours. The polymer obtained had a reduced viscosity of 13.8, and a small amount of formic acid-insoluble polymer was produced. The content of primary amide group was 6.06 mmol / g.

Example 5 A double-tube polymerization machine comprising an inner diameter 1.0 cm, an outer diameter 1.3 cm and a length 30 cm of a stainless steel inner tube and an inner diameter 3.0 cm, an outer diameter 3.5 cm and a length 30 cm of a stainless steel outer tube was used. Silicon oil was circulated as a heat medium in the space between the inner tube and the outer tube, and polymerization was performed as follows.

That is, 20 _{g of} acrylamide monomer and 0.0044 _g of calcium dipropoxide (1 / 10,000 mol based on the monomer) were uniformly mixed and charged into an inner tube, and the pressure inside the system of the inner tube was reduced to about 60 Torr by a vacuum pump. After that, the atmosphere is replaced with nitrogen gas. Silicone oil at 90 ° C is circulated in the space between the inner tube and the outer tube to completely melt the monomer. Next, the temperature of the circulating heat-transfer silicon oil is raised to 100 ° C. for 1.5 hours and 110
After keeping the temperature at 1.5 ° C for 1.5 hours, at 120 ° C for 1.5 hours, and at 130 ° C for 1.5 hours, finally hold at 170 ° C for 3 hours and then cool.

Next, the rod-shaped polymer in the inner tube made of stainless steel was taken out, crushed, washed with acetone, and then dried at 70 ° C. for 24 hours under a vacuum of about 5 torr. The conversion from monomer to polymer is calculated by the formula It was 98% when calculated by.

As a result of analysis, the content of primary amide groups in the polymer was 6.41 mmol / g, the content of formic acid was 60%, and the content of insoluble was 4%.
It was 0%. The reduced viscosity of the formic acid-soluble portion was 6.1.

Reference Example 1 100 parts by weight of powdered acetylated polyoxymethylene resin (standard load of 2.16 kg according to ASTM-D-1238-57T, melt index at temperature 190 ° C. of 15.4 g / 10 minutes), antioxidant [2,2'-methylenebis (4-methyl 6-t-butylphenol)] 0.25 parts by weight, 0.5 parts by weight each of the acrylamide unit-containing β-alanine copolymers produced in Examples 1 to 5 and Comparative Examples 1 and 2. Were mixed with a Henschel mixer and extruded at 200 ° C. in an extruder to pelletize. The pellets were dried with hot air at 80 ° C. for 14 hours. The thermal stability and residence color of the dried pellets were measured. The results are shown in Table 3.

Reference Example 2 Pellets were prepared in the same manner as in Reference Example 1 except that a ternary copolymerized polyamide of hexamethylene adipamide, hexamethylene sebacamide and caprolactam was used instead of the acrylamide unit-containing β-alanine copolymer. Was made and the same evaluation was performed. The results are shown in Table 3.

Reference Example 3 A polyhexamethylene adipamide (nylon 66) mixture dispersed in ethylene and a methyl acrylate copolymer was used as a polyamide in place of the β-alanine copolymer containing an acrylamide unit, and 0.5 part by weight was used as a polyamide. A pellet was prepared by the same method as in Reference Example 1 and the same evaluation was performed. The results are shown in Table 3.

As is clear from this table, the amount of catalyst per mol of acrylamide is less than 1/20000 mol (Comparative Example 1) and 1
If more than 5000 mol / mol (Comparative Example 2) is used, the thermal stability is poor.

Reference Example 4 Powdery terminally acetylated polyoxymethylene resin
100 parts by weight, 0.25 part by weight of antioxidant [2,2′-methylenebis (4-methyl-6-t-butylphenol)], acrylamide unit-containing β synthesized in Example 1 and Example 2
0.5 parts by weight of an alanine copolymer and 0.2 parts by weight of carbon black as an additive or 0.2 parts by weight of titanium oxide were mixed in a Henschel mixer, extruded at 200 ° C. in an extruder, and pelletized. The pellets are dried with hot air at 80 ° C for 14 hours,
The weight reduction rate was measured by the same method as in Reference Example 1. The results are shown in Table 4.

Reference Example 5 The procedure of Reference Example 4 was repeated, except that the ternary copolymerized polyamide used in Reference Example 2 was used in place of the acrylamide unit-containing β-alanine copolymer. The results are shown in Table 4.

Reference Example 6 The procedure of Reference Example 9 was repeated, except that the polyamide used in Reference Example 3 was used instead of the acrylamide unit-containing β-alanine copolymer. The results are shown in Table 4.

Reference Example 7 The polymer of Example 1 was dissolved in hot water, coated on a glass plate, and dried to form a thin film. As a result of examining the peelability by using a cellophane tape in the goggles test to examine the adhesiveness, it was found that the peeling was zero and the polymer had excellent adhesiveness.

Reference Example 8 The random copolymer 1 obtained in Example 1 was added to 10 g of clay soil.
After adding 200 g of water containing 000 ppm and stirring well, the mixture was filtered with a glass filter. The filtration speed at this time is 0.09 m ³ / m ² h
It was r. As a comparative example, 200 g of water was added to 10 g of the same clay soil, and the mixture was thoroughly stirred and then filtered through a glass filter.
The filtration rate at this time was 0.03 m ₃ / m ₂ hr. That is,
The filtration rate was tripled due to the soil aggregation effect of the β-alanine copolymer containing acrylamide units.

[Brief description of drawings]

FIG. 1 is a β-containing high molecular weight acrylamide unit of the present invention.
Infrared absorption spectrum of one example of an alanine copolymer, 2nd
The figure is a carbon-13 nuclear magnetic resonance spectrum of the formic acid-soluble poly-β-alanine polymer.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location D21H 19/20 // C09K 17/00 D D01F 6/68 7199-3B D06M 15/59 7199-3B D21H 3/58 // D06M 15/59

Claims (3)

[Claims] 1. A formula A structural unit (I) represented by Of the structural unit (II), the content of the primary amide group in the structural unit (II) is 4.9 to 7.0 mmol per 1 g of the polymer, and the reduced viscosity (η _sp / c) is at least A β-alanine copolymer containing a high molecular weight acrylamide unit characterized by having a content of 2 dl / g. 2. A β-alanine copolymer containing a high molecular weight acrylamide unit according to claim 1, which has a reduced viscosity (η _sp / c) of 2 to 15 dl / g. 3. Acrylamide is 1/50 to 1 mol of the acrylamide.
The formula is characterized by using 00 to 1/20000 mol of an alkaline earth metal alcoholate catalyst and polymerizing in a reaction system free from impurities. A structural unit (I) represented by A method for producing a β-alanine copolymer containing a high molecular weight acrylamide unit, which comprises the structural unit (II)