JPS6166707A - Production of crosslinkable, thermally reversible high polymer compound - Google Patents

Abstract

PURPOSE:To obtain the titled novel compound useful in a wide field such as a light screening material for green house, etc., a separating membrane, etc., easily crosslinkable by heating, by copolymerizing radically a specific compound with N-methylolacrylamide in a solution state. CONSTITUTION:1mol compound (e.g., N-isopropylacrylamide, etc.) shown by the formula I (R1 is H, or methyl; R2 is n-propyl, isopropyl, or cyclopropyl) is radically polymerized with <=1mol N-methylolacrylamide shown by the formu la CH2=CH-CONHCH2OH in a solvent such as water, etc. in a solution state, to give the aimed compound consisting of units shown by the formula III and the formula IV. Preferably the reaction is carried out at 100-200 deg.C for 1-150min.

Description

Detailed Description of the Invention a. Industrial Application Field The present invention relates to a novel thermoreversible polymer compound having crosslinking properties and a method for producing a crosslinked molded product thereof, and these compounds and a crosslinked molded product thereof are It is thought that it will be used in industrial fields such as light-shielding bodies for greenhouses, toys, interiors, water-breathing bodies, coatings, printing agents, adhesives, separation membranes, mechanochemical materials, etc.

b. Conventional technology Among water-soluble polymer compounds, those that exhibit a special reversible dissolution behavior in which they precipitate and become cloudy at a temperature above a certain temperature (transition temperature or cloud point) in an aqueous solution state, and dissolve and become transparent below that temperature. It is called a reversible polymer and is being applied to light shielding materials, adsorbents, etc. However, thermoreversible polymers may dissolve in water and dissipate at low temperatures. Therefore, when using this, except for cases such as light shielding bodies in which the aqueous solution is injected into laminated transparent plate bodies, cross-linking molding is required to maintain the shape under low temperature conditions and prevent its dissipation. Some kind of insolubilization/immobilization must be performed, such as oxidation or grafting onto a carrier. If simple insolubilization and immobilization were possible, the scope of use of thermoreversible polymers would be significantly expanded to include separation membranes, mechanochemical materials, etc., as shown in the example of Al.

C Problems to be Solved by the Invention The purpose of the present invention is to eliminate the above-mentioned problems of thermoreversible polymers, and specifically, to produce a novel thermoreversible polymer having crosslinking properties. It is an object of the present invention to provide a method and a simple method for crosslinking the obtained crosslinkable thermoreversible polymer.

d Means for Solving the Problems In view of the above circumstances, the inventors of the present invention should develop a crosslinked molded body of thermoreversible polymer (as a result of continued research, the general formula: CH=CC
0NHRx t' table N-methylol acrylamide (CH2=CH-Co-NH-CH
It was discovered that a copolymer obtained by radical copolymerizing in a solution state by adding 20H) in an amount not exceeding 1 mole has thermoreversible properties and thermal crosslinking properties, and based on this knowledge, the present invention was completed. Ta.

That is, the first feature of the present invention is that the general formula CHz""C
N-methylolacrylamide (CH2=CH-CONHC&OH) to 1 mol of the compound represented by C0NHRt,
The purpose is to produce a thermoreversible polymer having crosslinking properties by adding not more than 1 mol of the polymer and carrying out radical copolymerization in a solution state using a bulk or uniformly miscible solvent as a reaction medium. Such a reaction medium is not particularly limited, but may include water, alcohol i, N, N-diethylacetamide, dimethyl sulfoxide, acetone, dioxane, tetrahydrofuran, benzene, chloroform, carbon tetrachloride, etc. They may be used alone or in combination of two or more. In this case, the total concentration of copolymer components is not particularly limited, but is preferably 1 to 100%. The polymerization method may be radical polymerization (eg, radiation irradiation, light irradiation, or heating in the amount of a normal radical polymerization initiator), and any commonly known method can be used.

This copolymer has an appropriate molecular weight for processing into molded articles, such as a chloroform solution or a methanol solution with an intrinsic viscosity [η] of 0.01 to 6.0 at 30°C.
It is practical to have a value of [η) = 0.1 to 3.0.
Preferably.

In the copolymer obtained by the method of the present invention, N-methylol groups undergo a dehydration reaction upon heating and are easily crosslinked. The second feature of the present invention resides in a simple method for producing a thermoreversibly crosslinked molded article that takes advantage of this fact. That is, according to the method of the present invention, it is possible to obtain a water-insoluble crosslinked molded product simply by dry heat treating a sample made of a copolymer molded by any method such as casting or wet spinning. The crosslinking reaction conditions depend on three factors: B unit content in the copolymer, reaction temperature, and reaction time. In general 1ζ, if the B unit content is large, the reaction temperature is low and the reaction time is short.

If the B unit content is small, the reaction temperature is high (and the reaction time is long. Usually, a reaction temperature of 100°C to 200°C and a reaction time of 1 to 500 minutes is preferable.

The transition temperature of the thermoreversible polymer compound aqueous solution obtained by the method of the present invention depends on the type of A unit and the content of B unit. That is, the transition temperature moves from the transition temperature of only A units to a higher temperature side as the content of B units in the copolymer increases. B
When the unit content exceeds 50%, the polymer becomes water-soluble.

Therefore, there is a limit to the content of B units in the copolymer, and although it depends on the type of A, the B unit content is 0.1 mol%.
~50 mol%.

The transition temperature changes depending on the content of B units.
- face, which means that the transition temperature can be adjusted, and therefore, according to the present invention, the B unit-containing MO11
A thermoreversible polymer crosslinked molded article having an arbitrary transition temperature depending on the purpose can be obtained within the range of mol % to 50 mol %.

A thermoreversible polymer consisting only of A units has extremely high thermal response sensitivity, and its aqueous solution instantaneously becomes cloudy or transparent at the transition temperature. This sensitivity decreases as the B unit content increases due to copolymerization with the B unit component. However, the rate of decrease is small, and the thermal response sensitivity of the crosslinkable thermoreversible polymer in the method of the present invention is good.

e Example Next, the present invention will be explained in detail with reference to Examples.

Example I N-methylolacrylamide and N-isopropylacrylamide (CHz = C-C0NHCH(CH3)
Copolymers with various composition ratios were produced by changing the combination and amount of 2). Using azobisisobutyronitrile as a polymerization initiator, 2011L of methanol solution with a concentration of 5~/-
() was added to a monomer solution with a predetermined composition and concentration and reacted for 14 hours at a reaction temperature of 50°C. After the reaction, the reaction solution was made into an acetone solution and precipitated in diethyl ether to recover the polymer. In the copolymer The N-methylol acrylamide fraction was calculated assuming a polymerization rate of 10,096.

The transition temperature of the obtained thermoreversible polymer was determined from the change in transmittance associated with the temperature of its aqueous solution. That is, 196
When an aqueous polymer solution of a degree is prepared, set in a spectrophotometer with temperature control, and the change in light transmission at a wavelength of s o o nm is measured while increasing the temperature at a rate of 1°C/mjn, the results in Figure 1 are obtained. You will get results like this.

The transition temperature was determined from the point in this figure where the optical transmittance is at the initial transmittance.

Table 1 summarizes the amount of monomer charged, the N-methylolacrylamide fraction in the copolymer, and the transition temperature in each experiment.

Table 1 Charge amount Polymer 1 0 2.05 0 30.32
0.11 1.96 5.3 33.03
0.28 1.79 13.5 37.
54 0.54 1.61 25.1 4
4.05 0.69 1.69 29.0
47.06 1.02 1.06 49.
0 77.57 2.02 0 100
- From these results, it was found that the copolymer obtained has excellent thermal response sensitivity and that the transition temperature can be varied over a wide range depending on the content of N-methylolacrylamide in the copolymer.

In addition, the sample of experiment Nα3 was molded into a film, and 150
When dry-heated at ℃ for 1 hour, crosslinking was observed while maintaining the shape before heating.

Example 2 N-methylolacrylamide and N-n-propylacrylamide (C=CHC0NH(CH2)2CH
Copolymers having various composition ratios were produced by changing the combinations and amounts of 3). Using azobisisobutyronitrile as a polymerization initiator, a methanol solution with a concentration of 5M9/mJ 25
No. 17 was added to a monomer solution having a predetermined composition and concentration, and the reaction was carried out at a reaction concentration of 50° C. for 400 hours. After the reaction, the methanol solution was made into an acetone solution, and the polymer was recovered by precipitation in diethyl ether. The N-methylolacrylamide fraction in the copolymer was calculated assuming a polymerization rate of 10,096.

The °1 transition temperature was determined by the method of Example 1.

Table 2 summarizes the relationship between the amount of monomer charged, the N-methylolacrylamide fraction in the copolymer, and the transition temperature in each experiment.

Table 2 Charge amount Polymer 13 0 2.25 0 21.0
14 0.11 2.15 5.4
24.015 020 2.04
9.9 27.216 0.40 1.8
0 19.9 32.317 0.61
1.58 30.1 39.018
0.90 1.26 44.4 56.5
19 120 0.91 59.6
- From these results, as in Example 1, it was found that the transition temperature could be varied over a wide range depending on the N-methylolacrylamide content in the copolymer.

In addition, the sample of experiment Nl115 was molded into a film shape, and 1
When dry heated at 50°C for 1 hour, it was observed that the shape before heating was maintained and crosslinking occurred.

Example 3 N-methylolacrylamide and N-cycloH-propylacrylamide (CH2=CH-CONH-C
Copolymers with various composition ratios were produced by changing the combination and charging amount of HI)Cl. Using azobisisobutyronitrile as a polymerization initiator, its concentration was 5119/m/methanol solution 2011
A monomer solution having a predetermined composition and concentration was added to No. 11, and the mixture was reacted at a reaction temperature of 50° C. for 40 hours.

After the reaction, the methanol solution was made into an acetone solution, and the polymer was recovered by precipitation in diethyl ether.

The N-methylolacrylamide fraction in the copolymer was calculated assuming a polymerization rate of 10,096. The transition temperature was determined by the method of Example 1.

Table 3 summarizes the relationship between the amount of monomer charged, the N-methylolacrylamide fraction in the copolymer, and the transition temperature in each experiment.

3rd table charging lid Polymer 22 0 2.20 0 45.02
3 0.19 1.96 9.6 55
．． 624 0.40 1.76 20.0
67.225 0.58 1.50 2
9.8 81.626 0.87 1.33
41.8 -27 0.99 113
49.0 - From these results, as in Example 1, it was found that the transition temperature could be varied over a wide range depending on the content of N-methylolacrylamide in the copolymer.

Further, when a sample obtained by molding the sample of Experiment Nα23 into a film shape was heated at 150° C. for 1 hour, it was observed that the sample maintained its shape before heating and was crosslinked.

Example 4 N-methylol acrylamide and N-isopropylmethacrylamide (CH2=CC0NHCH(C
Copolymers with various composition ratios were produced by changing the combinations of Hz) and 2) and the amount of charge. Using azobisisobutyronitrile as a polymerization initiator, methanol solution 2 with a concentration of 5*/d
0.0 L was added to a 7-mer solution with a predetermined composition and concentration, and the mixture was reacted at a reaction temperature of 50°C for 70 hours. After the reaction, the methanol solution was made into an acetone solution, and the polymer was recovered by precipitation in diethyl ether. The N-methylolacrylamide fraction in the copolymer was calculated assuming a polymerization rate of 10,096. The transition temperature was determined by the method of Example 1.

Table 4 summarizes the relationship among the amount of monomer charged, the N-methylolacrylamide fraction in the copolymer, and the transition temperature in each experiment.

Table 4 Charge amount Polymer 33 1.02 1.4U
4/, 6 8 (j, Z) From these results, it was found that, as in Example 1, the transition temperature could be varied over a wide range depending on the content of N-methylolacrylamide in the copolymer.

In addition, the sample of experiment Nα29 was molded into a film shape, and 15
When heated at 0''C for 1 hour, it was observed that the shape before heating was maintained and crosslinking occurred.

Example 5 A methanol solution containing 1.30 g of N-methylolacrylamide, 12.07 g of N-isopropylacrylamide, and azobisisobutyronitrile (concentration 5 to 1
00rLt was placed in an ampoule, degassed under reduced pressure using liquid nitrogen, and the upper part was sealed with a burner. 50°C
The mixture was placed in a constant temperature bath and allowed to stand for 24 hours to polymerize. After the reaction,
The container was opened and methanol was removed under reduced pressure. Furthermore, this was made into an acetone solution and precipitated in diethyl ether to recover the polymer.

The N-methylolacrylamide fraction in the copolymer is 1
It was 0.7%. The transition temperature of this copolymer 196 aqueous solution was 36.0°C. Further, the intrinsic viscosity of this copolymer was [η]=0.48, as determined by measuring the viscosity in a chloroform solution at 30°C.

Seven tons of this copolymer was dissolved, poured onto a Teflon plate, and air-dried to form a film. Table 5 shows the relationship between the processing conditions and the crosslinking state when this film-like molded product was subjected to dry heat treatment.

O: Not dissolved in water (crosslinked) As is clear from Table 5, a crosslinked molded product could be easily obtained by subjecting the film-like molded product to dry heat treatment.

f Effects of the Invention The present invention provides a method for producing a radical molecular compound in a solution state by adding N-methylolacrylamide to 1 mole of a compound represented by the general formula CH2=100NH-5 in an amount not exceeding 1 mole; The present invention relates to a method for producing a thermoreversible polymer crosslinked molded article, which comprises dry heating the copolymer after molding. Conventionally, poly(N-propyl(meth)acrylamide) compounds have been known to have thermoreversible properties, but the copolymer with N-methylolacrylamide, which is the subject of the present invention, has thermoreversible properties as well as It has cross-linking properties, and therefore has the property that it can be easily cross-linked by heat treatment after forming a molded object. Therefore, this copolymer is expected to be widely used in mechanochemical materials, light shielding materials, adsorbents, toys, separation membranes, etc.

[Brief explanation of the drawing]

FIG. 1 shows the experiment Nal, Nn3, Nao5, N1 of Example 1.
16 is a transmittance-temperature curve of the thermoreversible polymer aqueous solution obtained in step 16.

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R_1 is a hydrogen atom or a methyl group, R_2 is n-
They are propyl group, isopropyl group, and cyclopropyl group. ) is characterized by adding N-methylolacrylamide CH_2=CH-CONHCH_2OH in an amount not exceeding 1 mole to 1 mole of the compound represented by ▲Mathematical formula, chemical formula, table, etc.▼Unit and ▲Mathematical formulas, chemical formulas, tables, etc. ▼Production method of crosslinkable thermoreversible polymer compound consisting of units