JPH0356579B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing a thermosetting resin.

When a bis(2-oxazoline) compound and a dicarboxylic acid are heated in the presence of a catalyst such as a phosphite at a ratio of 1 mole or less of dicarboxylic acid per 1 mole of the bis(2-oxazoline) compound, the bis(2-oxazoline) compound and dicarboxylic acid are heated.
Polyesteramide is temporarily generated by the reaction between the oxazoline compound and the dicarboxylic acid, but
The active hydrogen of the -NHCO- group in this polyesteramide and the 2- of the bis(2-oxazoline) compound
Further reaction with the oxazoline ring results in crosslinking and a thermosetting resin is obtained.

A specific method for producing this resin is a method in which a bis(2-oxazoline) compound, a dicarboxylic acid, and a catalyst are simultaneously melted, that is, a one-step method, but this method has the following drawbacks.

Most of the raw material bis(2-oxazoline) compounds and dicarboxylic acids are solid at room temperature, and many have melting points of 100°C or higher. Therefore, melting is usually carried out at temperatures above 100°C, but at this temperature, the reaction between the dicarboxylic acid and the bis(2-oxazoline) compound and the reaction between the amide group and the 2-oxazoline ring produced by the reaction proceed rapidly. However, once it has melted uniformly, the viscosity rapidly increases due to the reaction, resulting in gelation. For this reason, it is difficult to obtain a large molded product without bubbles or a molded product containing a filler.

The reaction between bis(2-oxazoline) compounds and dicarboxylic acids is an exothermic reaction;
When a compound (oxazoline) and a dicarboxylic acid are mixed and melted all at once, a large amount of heat is generated. The generated heat accumulates in the molded product, causing cracks and scorches.

As a result of intensive studies by the present inventors on a manufacturing method that does not have the above-mentioned drawbacks, we found that when a small amount of other components are added to a bis(2-oxazoline) compound or dicarboxylic acid, the melting point is significantly lowered. We discovered that they are completely stable, and that when a thermosetting resin is produced by mixing their melts, each component has already reacted, so the amount of heat generated when they are mixed is extremely small. Based on this knowledge, we have completed the present invention. That is, the present invention provides a liquid A containing a bis(2-oxazoline) compound and about 0.7 mol or less of dicarboxylic acid per 1 mol of the bis(2-oxazoline) compound, and which becomes liquid upon heating. Solution B, which contains a dicarboxylic acid and about 0.7 mol or less of a bis(2-oxazoline) compound per 1 mol of the dicarboxylic acid and becomes liquid when heated, is mixed with a bis(2-oxazoline) compound relative to the dicarboxylic acid. This is a method for producing a thermosetting resin, which is characterized by mixing the compound (oxazoline) in excess in terms of molar ratio and heating if necessary.

Bis(2-oxazoline) used in the present invention
Examples of the compound include 1,2-bis(2-oxazolinyl-2)ethane, 1,4-bis(2-
Oxazolinyl-2)butane, 1,6-bis(2)
Compounds in which an oxazoline ring is bonded to an alkyl chain such as -oxazolinyl-2)hexane, 1,8-bis(oxazolinyl-2)octane, and 1,4-bis(2-oxazolinyl-2)cyclohexane, such as 1,2-bis (2-oxazolinyl-2)benzene, 1,3-bis(2-oxazolinyl-2)benzene, 1,4-bis(2-oxazolinyl-2)benzene, 5,5'-dimethyl-
2,2'-bis(2-oxazolinyl-2)benzene, 4,4,4',4'-tetramethyl-2,2'-bis(2-oxazolinyl-2)benzene, 1,2
-bis(5-methyl-2-oxazolinyl-2)
Benzene, 1,3-bis(5-methyl-2-oxazolinyl-2)benzene, 1,4-bis(5-
Methyl-2-oxazolinyl-2) Two oxazoline rings are bonded to an aromatic nucleus such as benzene, and those represented by the following general formula and 2,2'-
Bis(2-oxazoline), 2,2'-bis(4-
methyl-2-oxazoline), 2,2'-bis(5
-methyl-2-oxazoline).

[In the formula, R represents a divalent hydrocarbon group, and R ₁ to _{R 4} represent hydrogen or a hydrocarbon group. ] Examples of dicarboxylic acids include malonic acid, succinic acid, adipic acid, pimelic acid, suberic acid,
Aliphatic dicarboxylic acids such as azelaic acid, sebacic acid, dodecanedioic acid, dimer acid, eicosanedioic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenylmethane dicarboxylic acid. Acid can be given. Two or more of these may be used in combination.

In the present invention, the aforementioned bis(2-oxazoline)
A compound containing a bis(2-oxazoline) compound and a dicarboxylic acid of about 0.7 mol or less, preferably about 0.15 to 0.40 mol per mol of the bis(2-oxazoline) compound, is heated using a compound and a dicarboxylic acid. This creates a liquid A solution.

Next, using a bis(2-oxazoline) compound and a dicarboxylic acid, about 0.7 mol or less, preferably about 0.7 mol or less, preferably about
A liquid B containing 0.20 to 0.55 mol of a bis(2-oxazoline) compound and becoming liquid by heating is prepared.

Bis(2-
The (oxazoline) compound and the dicarboxylic acid may be the same or different.

High melting points and poor compatibility with dicarboxylic acids and bis(2)
-oxazoline) compounds, such as isophthalic acid, fumaric acid, 1,4-bis(2-oxazolinyl-2)benzene, etc., are compatible with adipic acid and 1,3-bis(2-oxazolinyl-2)benzene, which have a relatively low melting point and good compatibility. 2) By combining with benzene etc., low viscosity and transparent liquids A and B can be provided.

The temperature at which liquids A and B become liquid varies depending on the type and amount of the dicarboxylic acid and bis(2-oxazoline) compound, but is usually 50°C or higher, preferably in the range of about 120 to 180°C.

Although liquids A and B are preferably completely liquid, a small amount may be in the form of a slurry in a crystalline to semi-molten state.

The time required for heating and melting varies depending on the raw materials used, the heating temperature, etc., but it is sufficient as long as it provides a transparent liquid with a constant viscosity, and is usually about 0.5 to 3 hours.

When preparing liquids A and B, it is preferable to melt them under a nitrogen stream since they may be colored due to oxidation. Furthermore, if necessary, an antioxidant can be added to suppress discoloration. As the antioxidant, phenolic antioxidants such as 2,6-ditertiarybutyl-p-cresol, Irganox 1010, and Irganox 1076 are preferably used.

The catalyst for producing the thermosetting resin may be added when mixing the A liquid and the B liquid, or may be added to the B liquid side in advance.

Electrophilic reagents such as phosphorous acid esters, organic phosphonic acid esters, and inorganic salts are effective as catalysts. Among these three types, phosphite esters are the most advantageous in terms of catalytic ability, solubility in the system, and side effects. Examples of phosphite include triphenyl phosphite, tris(nonyl phenyl) phosphite, triethyl phosphite, tri-n-butyl phosphite, tris(2-ethylhexyl) phosphite, and tristearyl phosphite. , diphenyl monodecyl phosphite, tetraphenyl dipropylene glycol diphosphite,
Tetraphenyltetra(tridecyl)pentaerythritol tetraphosphite, diphenyl phosphite, 4,4'-butylidene bis(3-methyl-6-t-butylphenyl-di-tridecyl) phosphite, bisphenol A pentaerythritol phosphite , diphenyl hydrogen phosphite, etc. Two or more types of these may be used. Among the above, phosphorous acid esters containing a phenolate group or a substituted phenolate group are particularly preferred.

Examples of esters of organic phosphonic acids include diphenyl phenylphosphonate, di(β-chloroethyl) β-chloroethylphosphonate, and 4,4′-
Biphenylene diphosphonic acid tetrakis (2,4-
Examples include esters of aliphatic or aromatic phosphonic acids such as di-t-butylphenyl).

As the inorganic salts, various salts that dissolve in the system are effective. It is better not to have crystal water. For example, mono- to tetravalent cations (vanadyl Examples include salts consisting of a combination of polyatomic cations (including polyatomic cations such as chlorine and zirconyl) and anions such as halogen, nitric acid, sulfuric acid, and chloric acid. Among them, cupric chloride, vanadium chloride, vanadyl chloride, cobalt nitrate, zinc chloride, manganese chloride, bismuth chloride, etc. show excellent catalytic ability.

The amount of catalyst is about 0.05% by weight or more, preferably 0.2% by weight or more based on the resin raw material.

In the present invention, a thermosetting resin is obtained by mixing liquid A and liquid B and heating if necessary.

The mixing ratio of liquid A and liquid B is determined by the molar ratio of the bis(2-oxazoline) compound to the dicarboxylic acid in excess, that is, the dicarboxylic acid to bis(2-oxazoline) compound.
The molar ratio of the (oxazoline) compound is arbitrarily selected within the range of about 1 or less, preferably from about 0.2 to 1, but in general, from the viewpoint of ease of mixing, the mixing ratio of liquid A and liquid B is determined by weight. About 9 to 7, while liquid B is about 1 to 7.
It is best to set it to 3.

Any device may be used to adjust and mix liquids A and B, and is not particularly limited. A container, a metering pump that can feed a fixed amount of liquids A and B, and this A.
A two-component or three-component casting machine is conveniently used, which is equipped with a mixing head that mixes and discharges the liquid, B liquid, and catalyst uniformly and without forming bubbles.

A thermosetting resin can be obtained by keeping the mixture of A and B at the mixing temperature for about 2 minutes to 2 hours, but if the mixing temperature is low, the thermosetting resin will be about 150
Curing may be accelerated by heating to ~250°C. The heating time is about 2 minutes to 2 hours.

The thermosetting resin thus obtained has an ester group, a secondary amide group, and a tertiary amide group in the molecule, and is strong and has excellent abrasion resistance and solvent resistance. This thermosetting resin can be used, for example, in the molding of mechanical parts such as rolls and gears, in the molding of electrical parts, electrical insulators, dental materials, and the like.

The method of the invention has the following advantages.

The prepared liquids A and B have a low crystallization temperature, and because part of the reaction during curing has already occurred during melting, less heat is generated during curing. Therefore, (a) it can be used for molding large molded objects.

(b) It is easy to mix in fillers and reinforce glass fibers and carbon fibers.

(c) Natural defoaming is possible, and degassing operations such as decompression can be easily performed if necessary, so a cured product without bubbles can be produced. If you use a casting machine, you can more easily obtain a foam-free product.

Liquids A and B remain stable forever unless they are mixed.

It has much greater stability than the general method of producing resin by simultaneously melting a bis(2-oxazoline) compound, dicarboxylic acid, and catalyst.
Suitable for continuous production, etc.

Since liquids A and B are each stable, even raw materials with high melting points and poor compatibility can be melted at high temperatures for a long time and can be used as resin raw materials.

The present invention will be explained in more detail with reference to Examples below.

Example 1 1,3-bis(2-oxazolinyl-2)benzene 87.5g (0.40mol) and adipic acid 12.5g
(0.09 mol) is weighed in a beaker, melted uniformly, and kept at 135°C (Liquid A). 38 g (0.18 mol) of 1,3-bis(2-oxazolinyl-2)benzene, 62 g (0.42 mol) of adipic acid, and 1.7 g of triphenyl phosphite were weighed in a beaker and uniformly melted.
Keep at 130℃ (solution B). Ratio of A liquid 7 and B liquid 3 (adipic acid/1,3-bis(2-oxazolinyl-
2) Weigh with benzene molar ratio = 0.55),
Stir well in an oil bath at 120°C. Immediately after mixing
It is less than 200cps, and after 5 minutes it is less than 400cps,
It became 1000 cps after 10 minutes and gelled after 27 minutes, yielding a thermosetting resin. Both A and B liquids have low viscosity,
It had an extremely long pot life.

Example 2 After uniformly melting 80 g (0.37 mol) of 1,3-bis(2-oxazolinyl-2)benzene and 20 g (0.14 mol) of adipic acid, 20 g of milled fiber was prepared.
Add, mix well, and keep at 130℃ (liquid A). 1,
3-bis(2-oxazolinyl-2)benzene43
After uniformly melting 57 g (0.39 mol) of adipic acid and 3.3 g of triphenyl phosphite, 5 g of milled fiber was added, mixed well, and kept at 125°C (solution B). Weigh out the ratio of Part A 7 and Part B 3 (molar ratio of adipic acid/1,3-bis(2-oxazolinyl-2)benzene = 0.66), mix well, defoam under reduced pressure, and add a 3 cm spacer. The mixture was poured into aluminum casting molds held at 200°C, and cured at 200°C for 30 minutes. A cured product without bubbles was obtained. After taking a part of this cured product and heating it in 4N-NaOH to hydrolyze it,
The degree of crosslinking determined by quantifying monoethanolamine by gas chromatography was 35%.

Example 3 1,3-bis(2-oxazolinyl-2)benzene 9.19Kg (42.55mol) and adipic acid 1.31Kg
(8.90 mol) is uniformly melted in a container equipped with a heating device and kept at 140°C (Liquid A). 1,3- in another container
Bis(2-oxazolinyl-2)benzene 2.28Kg
(10.55 mol), 3.72 kg (25.48 mol) of adipic acid, and 0.20 kg of triphenyl phosphite were uniformly dissolved and kept at 135°C (solution B). A ratio of 7 parts of liquid A and 3 parts of liquid B were weighed and mixed (molar ratio of adipic acid/1,3-bis(2-oxazolinyl-2)benzene = 0.55). The mixed liquid had a viscosity of 500 cps or less at 145°C, and no bubbles were observed. The viscosity of each liquid was measured after a certain period of time (1, 3, 5, 7 hours) while maintaining the temperature of liquids A and B, and the thermal measurement of a cured product (heated at 200℃ x 20 minutes) made using the mixed liquid was carried out. The properties (thermal strain temperature) were investigated, but no change was observed.

The degree of crosslinking of the cured product was 48%.

Example 4 1,3-bis(2-oxazolinyl-2)benzene 11.52Kg (53.28mol), adipic acid 2.88Kg
(19.71 mol) and 0.072 kg of 2,6-ditertiarybutyl para-cresol were uniformly melted under a nitrogen atmosphere and kept at 140°C (liquid A). 1,3 in another container
-bis(2-oxazolinyl-2)benzene
2.175Kg (10.06mol), adipic acid 2.825Kg (19.33
mol) and 0.125 kg of triphenyl phosphite are uniformly melted and kept at 135°C (solution B). Adjust the metering pump so that 800 g of liquid A and 200 g of liquid B (mole ratio of adipic acid/1,3-bis(2-oxazolinyl-2)benzene = 0.55) are fed per minute and mixed. 7.5 kg of this liquid mixture was filled into a tin cylinder having an outer diameter of 220 mm, an inner diameter of 110 mm, and a height of 230 mm, and was allowed to harden at room temperature and then at 200° C. for 2 hours. A roll-shaped molded product with no bubbles and no curing defects was obtained. The degree of crosslinking of this molded product was 52%.

Example 5 1,3-bis(2-oxazolinyl-
2) Weigh 85 g (0.39 mol) of benzene and 1 g of 2,6-ditertiarybutyl p-cresol, melt them, and keep at 180°C. While maintaining this temperature, 15 g (0.09 mol) of isophthalic acid is added little by little over about 1 hour and dissolved. Then cool to 145℃
(Liquid A). Meanwhile, 25 g (0.12 mol) of 1,3-bis(2-oxazolinyl-2)benzene, 75 g (0.51 mol) of adipic acid, and 3 g of triphenyl phosphite were uniformly dissolved and kept at 130°C (B
liquid). Ratio of A liquid 7 and B liquid 3 (dicarboxylic acid/1,
The molar ratio of 3-bis(2-oxazolinyl-2)benzene=0.63) was weighed and mixed well to prepare a cured product. Unlike the case of the one-stage method, no undissolved isophthalic acid was observed in the cured product.

The physical properties of this cured product were as follows.

Bending strength 23.6Kg/mm ² Bending modulus 470Kg/mm ² Impact value (DINSTAT) 20Kg・cm/cm ² Heat strain temperature 133℃ Water absorption (23℃, 24hr) 0.50% Degree of crosslinking of cured product is 42% Ta.

Example 6 75 g (0.35 mol) of 1,3-bis(2-oxazolinyl-2)benzene and 25 g (0.12 mol) of sebacic acid were uniformly melted and kept at 135°C (liquid A). On the other hand, 30 g (0.14 mol) of 1,3-bis(2-oxazolinyl-2)benzene and 70 g (0.35 mol) of sebacic acid
(mol) and 1.7 g of triphenyl phosphite are uniformly dissolved and kept at 130°C (solution B). The mixture was weighed at a ratio of 7 parts A and 3 parts B (molar ratio of sebacic acid/1,3-bis(2-oxazolinyl-2)benzene = 0.66), and stirred well on an oil bath at 120°C. Immediately after mixing, it was about 200 cps or less, 5 minutes later it was about 400 cps, 10 minutes later it was about 900 cps, and it gelled after 36 minutes. The gelled product was kept at 180°C for 1 hour to obtain a cured product. The degree of crosslinking of this cured product was 33%.

Example 7 80 g (0.37 mol) of 1,3-bis(2-oxazolinyl-2)benzene and 20 g (0.11 mol) of azelaic acid
(mol) uniformly and kept at 135℃ (liquid A). Meanwhile, 30 g (0.14 mol) of 1,3-bis(2-oxazolinyl-2)benzene and 70 g of azelaic acid
(0.37 mol) and 2 g of triphenyl phosphite to make a homogeneous solution B. Ratio of 3 parts A and 1 part B (Azelaic acid/1,3-bis(2-oxazolinyl-
2) Weigh with benzene molar ratio = 0.55),
Stir well on a 120°C oil bath. Immediately after mixing, approx.
100 cps, about 300 cps after 5 minutes, about 600 cps after 10 minutes, gelatinized after 40 minutes, and a cured product was obtained.

Claims (1)

[Claims] 1 bis(2-oxazoline) compound and about 0.7 per mole of the bis(2-oxazoline) compound
Solution A, which contains dicarboxylic acid in an amount of about 0.7 mole or less per mole of the dicarboxylic acid and becomes liquid upon heating; A method of producing a thermosetting resin, which is characterized in that it is mixed with liquid B which has become liquid by mixing the bis(2-oxazoline) compound in an excess molar ratio with respect to the dicarboxylic acid, and is heated if necessary. Manufacturing method.