JPS6397613A - Production of condensed polycyclic aromatic resin - Google Patents

Abstract

PURPOSE:To obtain a resin of excellent heat resistance in good yield, by using a polar organic compound as a solvent in producing a condensed polycyclic aromatic resin by addition-polycondensing a polycyclic aromatic hydrocarbon with formaldehyde in the presence of an acid catalyst. CONSTITUTION:A polycyclic aromatic hydrocarbon (A) (e.g., naphthalene or an anthracene fraction of crude (tar), formaldehyde or a formaldehyde-generating substance (B) (e.g., methylal), and an acid catalyst (C) (e.g., p-toluenesulfonic acid) are dissolved in a solvent comprising a polar organic compound (e.g., nitrobenzene or nitromethane). Component A is addition-polycondensed with component B by slowly heating this solution to obtain the purpose condensed polycyclic aromatic resin. The obtained resin can be suitably used in electrical insulation materials and laminates which require heat resistance, and applications such as molding, filling, coating, etc., in various industrial fields.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a tar fraction containing polycyclic aromatic hydrocarbons as a raw material to produce a condensed polycyclic aromatic resin with excellent heat resistance through reaction. Regarding how to.

[Background of the invention]

As is well known, heat-resistant resins are electrically insulating materials, laminated products,
It is widely used as a molding material or a base material for composite materials. Phenol resin is a typical example of heat-resistant resin made from aromatic hydrocarbons, and various applications are being developed that take advantage of its excellent properties. However, in terms of resin raw materials, phenolic resins utilize special compounds such as phenol that have hydroxyl added to their aromatic rings, and cannot be said to be the direct use of aromatic hydrocarbons.

On the other hand, xylene resins obtained from meta-xylene and formaldehyde or resins related thereto are known as examples of using aromatic hydrocarbons as they are.

However, it is usually difficult to obtain polymers by reacting polycyclic aromatic hydrocarbons such as naphthalene or anthracene with formaldehyde alone, and special measures are required to obtain resins with satisfactory performance. be. For this reason, for example, as described in Japanese Patent Publication No. 35-8346, it is possible to improve the condensation reactivity and resin properties by adding a larger amount of phenols to the primary condensate with formaldehyde. It is being

However, even this type of method has problems such as low average molecular weight and poor thermal stability.

[Means for solving problems]

Based on this foreground, the present inventors have made repeated studies to overcome the drawbacks of the prior art described above, and have found that the addition of phenols can be prevented by using a certain type of solvent when carrying out the condensation reaction. The inventors have discovered that a polymer with excellent heat resistance can be obtained from at least a polycyclic aromatic hydrocarbon and formaldehyde, and have arrived at the present invention.

The present invention deals with neutral polycyclic aromatic hydrocarbons with 2 to 6 rings (hereinafter collectively referred to as polycyclic aromatic hydrocarbons) in a tar fraction, and formaldehyde or a substance that generates formaldehyde (hereinafter collectively referred to as formaldehyde). The present invention provides an improved method for producing a polycyclic aromatic resin having excellent heat resistance.

That is, the present invention has been made to achieve the above object, and when polycyclic aromatic hydrocarbon and formaldehyde are subjected to addition condensation in the presence of an acid catalyst to obtain a polycyclic aromatic resin, polar This method uses an organic solvent.

[For production]

According to the method of the present invention, a resin with extremely excellent heat resistance can be economically produced using a tar fraction containing polycyclic aromatic hydrocarbons as is.

Furthermore, the method of the present invention has the following advantages.

■ Target product can be obtained in a short time under mild reaction conditions ■ Soluble resin can be obtained as a homogeneous solution.

[Specific structure of the invention]

The present invention will be explained in detail below.

In the method of the present invention, a tar fraction containing polycyclic aromatic hydrocarbons or neutral polycyclic aromatic hydrocarbons with 2 to 6 rings (hereinafter collectively referred to as polycyclic aromatic hydrocarbons) is used as a raw material.

Here, the polycyclic aromatic hydrocarbon is an aromatic hydrocarbon whose main component contains 2 to 6 benzene rings. Specific examples of these polycyclic aromatic hydrocarbons are naphthalene, methylnaphthalene, dimethylnaphthalene, acenaphthene, fluorene, biphenyl, anthracene, phenanthrene, pyrene, chrysene, naphthacene, triphenylene, perylene, colon, and the like.

In addition, mixtures containing two or more of the above polycyclic aromatic hydrocarbons, such as carpol oil, naphthalene oil, cleaning oil, anthracene oil, ethylene bottom oil, solvent naphtha, coal tar, coal pitch, soft pitch, medium pitch, or Petroleum pitch, atmospheric residual oil, etc. can also be used as inexpensive raw materials. These may partially contain monocyclic aromatic hydrocarbons in addition to polycyclic aromatic hydrocarbons. As the tar fraction, it is appropriate to use an anthracene oil fraction contained in crude tar. If necessary, acid treatment, crystallization, filtration,
It is also effective to purify the product by conventional means such as distillation or sublimation before subjecting it to the reaction.

Formaldehyde and substances that generate formaldehyde (hereinafter collectively referred to as formaldehyde) used in the method of the present invention are substances that generate formaldehyde in the reaction system under the reaction conditions of the present invention, and specifically, trioxane. , paraformaldehyde, hexamethylenetetramine, methylal and other formals. In addition, an aqueous solution of formaldehyde (formalin) can be used as it is as a raw material.

Although there are no particular limitations on the type of polar organic solvent used in the present invention, examples of preferred solvents include the following. Di-lower alkyl formamides such as dimethylformamide and diethyl formamide; di-lower alkyl sulfoxides such as dimethyl sulfoxide and diethyl sulfoxide; di-lower alkyl acetamides such as dimethyl acetamide and diethylacetamide; lower alkyl shea such as acetonitrile and propionitrile; Aromatic cyanides such as benzonitrile, trinitrile; Aliphatic or aromatic nitro compounds such as nitromethane, nitroethane and nitrobenzene i# acids, carboxylic acids such as monochloroacetic acid, acid anhydrides such as acetic anhydride; monochloro Aromatic chlorides such as benzene and dichlorobenzene; methane chlorides such as methylene chloride, chloroform, and carbon tetrachloride; lower alkyl halides such as dichloroethane, dibromoethane, dichloropropane, trichloroethane, and tetrachloroethane; Aliphatic or aromatic ethers such as diethyl ether, diphenyl ether, dioxane, tetrahydrofuran; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone; organic sulfur compounds such as carbon disulfide, or mixtures thereof.

Among these, aromatic nitro compounds are particularly preferred, and a specific example thereof is nitrobenzene.

The condensation reaction in the method of the invention is carried out in the presence of an acid catalyst.

The range of acid catalysts used in the present invention includes both Bronsted acids and Lewis acids. In addition to inorganic mineral acids, organic acids, or liquid acids, solidified acids, zeolites, ion exchange resins, etc. are also used. Specific examples of preferred acids include inorganic mineral acids such as sulfuric acid, hydrochloric acid, phosphoric acid, and hydrofluoric acid, Lewis acids such as aluminum chloride, zinc chloride, boron trifluoride, and ferric chloride, trichloroacetic acid, and benzene. Organic acids such as sulfonic acid, p-)luenesulfonic acid, trifluoromethanesulfonic acid, formic acid, and oxalic acid.

The charging ratio of polycyclic aromatic hydrocarbon and formaldehyde as raw materials for the condensation reaction is generally 1/10 to 10 by weight when converted to 100% formaldehyde.
00/1, preferably 1/2 to 200/1, more preferably 115 to 50/1. Below the above range, the amount of formaldehyde will be insufficient and the resulting condensate (below the so-called B-stage prepolymer,
(referred to as prepolymer) has an insufficient degree of crosslinking. Further, if the amount exceeds the above range, formaldehyde is not only wasted, but also the properties of the final product are inferior, which is not preferable.

The preferred range of the amount of the solvent to be used is 1/2 to 10/1, preferably 1/1 to 5/1 in weight ratio to the raw material polycyclic aromatic hydrocarbon.

If the amount is below the above range, the raw materials and/or products will not be dissolved satisfactorily, making it impossible to achieve the object of the present invention. Further, if the temperature exceeds the above range, the scale of the equipment and the amount of utilities required will increase, which is uneconomical.

The amount of the acid catalyst added also depends on the type of acid, but a suitable range is from 1/100 to 1/1 by weight of the polycyclic aromatic hydrocarbon.

Below the above range, the reaction rate becomes extremely low. Moreover, if it exceeds the above range, not only is the catalyst wasteful, but also the burden of post-treatment steps such as waste acid treatment increases, which is not preferable.

A specific method for carrying out the polycondensation reaction in the present invention is as follows. The raw material polycyclic aromatic hydrocarbon and formaldehyde are mixed in an appropriate ratio and once dissolved in an organic solvent, a predetermined amount of acid catalyst is added at room temperature. In order to obtain a prepolymer with a uniform composition as much as possible, it is desirable to control the heating temperature at 20 to 90°C at the beginning of the reaction and then gradually increase the temperature.The final temperature is 80 to 18°C.
The temperature is maintained at 0°C, preferably in the range of 100 to 160°C. At 180° C. or higher, gelation occurs, which is not preferable.

The reaction time is not necessarily constant depending on the type of raw materials, the type of reaction solvent, and other conditions, but may range from 0.5 to 20 hours,
Preferably it is in the range of 1 to 10 hours. This time can also be freely selected depending on the desired properties of the prepolymer.

After heating and reacting with stirring for a predetermined period of time, the prepolymer produced is concentrated, precipitated, and processed to obtain the desired properties.
Separate and obtain by conventional means such as centrifugation and filtration.

Any procedure can be used for charging the polycyclic aromatic hydrocarbon and the polar organic solvent as long as the reaction is not inhibited. In the condensation polymerization reaction of the present invention, the reaction is allowed to proceed particularly under reflux, and when a predetermined condensation stage is reached, water, hydrochloric acid, etc. It is preferable to conduct the reaction while discharging condensation by-products such as the like from the system.

The reason for this is that if there is water in the solvent, it is difficult to produce a high molecular weight resin, and on the other hand, if the reaction is carried out while being dehydrated, the reaction proceeds smoothly.

In particular, solvents that form azeotropes with water, such as aromatic hydrocarbons, aliphatic or aromatic nitro compounds, aromatic chlorides, aromatic ethers, alkyl halides, are used, and the water produced in the reaction is continuously removed. Carrying out the condensation while removing the polymer is an effective means for improving the reaction rate and increasing the molecular weight of the prepolymer.

Moreover, the reaction format itself can be carried out either batchwise or continuously.

The solubilized condensed polycyclic aromatic resin produced by the method of the present invention is used as a heat-resistant resin and for applications such as casting, filling, and coating in various industrial fields.

〔Example〕

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

Parts herein are by weight unless otherwise specified.

(Example 1) 25 parts of phenanthrene, 5.3 parts of paraformaldehyde, 110 parts of p-)luenesulfone,
100 parts of nitrobenzene was charged, the temperature was raised to 120°C, the mixture was heated and stirred for 3 hours, and then the reaction solution was allowed to cool.

This reaction solution is poured into 1000 parts of methanol to precipitate the resin. Furthermore, after filtering and washing, drying under reduced pressure and pulverization were performed to obtain a resin.

The physicochemical properties of this resin were as follows.

Softening point 117℃ Pour point 131℃ Number average molecular weight 1194 The thermogravimetric changes are shown in Figure 1.

The prepolymer was analyzed by the following method.

(1) Softening point, pour point: Based on the flow tester method.

Load pressure 10 kg/c + a-G waste 11 dimensions
1 Sodium soda φ×2N Temperature increase rate 6° C./5 h (2) Heat chamber I reduction: Based on thermobalance method.

Sample 1 1 Q w (fine powder) Temperature increase rate 10℃/s+1n (3) Number average molecular weight: Based on vapor pressure osmotic pressure method.

Pyridine solvent (105°C) (Comparative Example 1) In the same apparatus as in Example 1, 25 parts of phenanthrene, 5.3 parts of paraformaldehyde, and 1.0 parts of p-toluenesulfonic acid were added.
Add 1 part and raise the reaction temperature to 12°C while stirring without solvent.
Heat it up to 0℃ for 30 minutes. After 30 minutes,
After cooling to 11011H while maintaining 120°C, 100 parts of chloroform was added to dissolve the product, and poured into 1000 parts of methanol with stirring to precipitate the resin. Thereafter, the powdered resin was prepared in the same manner as in Example 1. Obtained.

The properties of this resin were as follows.

Softening point 81℃ Pour point 87℃ Number average molecular weight 526 The thermogravimetric changes are shown in Figure 1.

(Comparative Example 2) 25 parts of phenanthrene, 5.3 parts of paraformaldehyde, 110 parts of p-toluenesulfone, and 100 parts of acetic acid were charged into a four-bottle flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube. The reaction was carried out for 3 hours while stirring at °C. Thereafter, a powdered resin was obtained in the same manner as in Example 1.

Softening point: 72°C Pour point: 86°C Number average molecule: 1 676 [Effects of the invention] As described above, by the method of the present invention, that is, the method of performing non-condensation in an organic solvent, polycyclic aromatic hydrocarbons and formaldehyde are used as raw materials. As such, resins with excellent heat resistance are more efficient. I! ! It is clear that it can be built.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing changes in thermal gravity of resins in Examples and Comparative Examples under nitrogen flow. Patent applicant Sumitomo Metal Industries, Ltd. Sugi Otani Department Representative Patent attorney Yoshi Nagai Figure 1 J & (C”)

Claims (1)

[Claims] 1) A method for obtaining a condensed polycyclic aromatic resin by carrying out addition condensation of a polycyclic aromatic hydrocarbon and formaldehyde or a substance that generates formaldehyde in the presence of an acid catalyst. A method for producing a condensed polycyclic aromatic resin, characterized by using a compound as a solvent. 2) The method according to claim 1, wherein the polycyclic aromatic hydrocarbon is a 2- to 6-ring polycyclic aromatic hydrocarbon in anthracene oil or a mixture thereof. 3) The method according to claim 1 or 2, wherein the polar organic compound is a nitro lower alkane or an aromatic nitro compound.