JPH075698B2 - Aromatic petroleum resin manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an aromatic petroleum resin, which has significantly better heat resistance and weather resistance than conventionally known petroleum resins. More specifically, an aromatic petroleum resin having a high heat resistance and a high weather resistance, which contains practically no double bonds and oxygen atoms, which adversely affect the heat resistance and the weather resistance, is produced from an aromatic compound and formaldehyde as raw materials. It is about the method.

(Prior Art) As is well known, a petroleum resin is generally produced by polymerizing a cracked oil fraction having a boiling point range of about 20 ° C to 280 ° C obtained by thermal decomposition of petroleum.

The aromatic petroleum resin generally uses, as a starting material, a fraction having a boiling point range of about 140 ° C. to 280 ° C. among the above fractions.
Since this fraction is mainly composed of aromatic olefins having 9 carbon atoms such as styrene and its derivatives, and indene and its derivatives, aromatic petroleum resins are also called C ₉ petroleum resins. There is.

A typical aromatic petroleum resin manufacturing method is
Add 0.01 to 5% by weight of boron trifluoride, aluminum chloride and other Friedel-Crafts type catalysts at -30 to 60 ° C for 10
The reaction is carried out for about 15 minutes to 15 hours, after the reaction is completed, the catalyst is decomposed and removed using an alkali, and finally unreacted oil and low molecular weight polymer are removed by distillation or the like to obtain a product.

There are various properties of the product depending on the use, but generally, it is a solid having a softening point of 60 to 190 ° C and a bromine number of about 20 to 40.

(Problems to be Solved by the Invention) In addition to the characteristics that petroleum resin has excellent physical properties such as water resistance and chemical resistance, since the supply is stable and the cost is low, paints, adhesives, Widely used in industrial fields such as adhesives, sealants, and rubber additives. However, conventional petroleum resins have drawbacks in heat resistance and weather resistance, which limits their use. It is said that the cause of poor heat resistance and weather resistance is the presence of a high degree of unsaturation due to the diolefins contained in the feed oil. Several methods are known to improve this defect and improve heat resistance and weather resistance. For example, a method in which the boiling point range of the feedstock is strictly regulated to suppress mixing of diolefins as much as possible (for example, Japanese Examined Patent Publication No. 34078, Sho 58-25705, etc.), and diolefins are more preferable than monoolefins. A method of synthesizing a petroleum resin by using a raw material oil mainly composed of monoolefins obtained by polymerizing a readily polymerizable compound centered on diolefins by utilizing the property of being easily polymerized (for example, Japanese Patent Publication No. Sho 49-2344, etc.) have been proposed.

However, it is difficult to completely remove diolefins by any of these methods, and an increase in cost due to the addition of a pretreatment step of the feedstock is unavoidable, and a sufficient improvement effect can be obtained. The current situation is not.

Further, the cause of the double bond is not necessarily caused only by the diolefins in the feed oil. In general, a feedstock oil used for producing an aromatic petroleum resin is mainly composed of aromatic olefins having a double bond in a side chain of an aromatic ring such as styrene and its derivatives, indene and its derivatives. As long as these olefins are cationically polymerized, even if it is assumed that diolefins are not completely present, double bonds are formed during the so-called transfer reaction and termination reaction in the polymerization process. It is inevitable that a double bond will occur in the resin.

In addition to the double bond caused by diolefins, the existence of an essential double bond resulting from the use of olefins in this raw material is considered to be petroleum, considering that the double bond is susceptible to an oxidation reaction. It must be considered that it has a bad influence on the heat resistance and weather resistance of the resin.

Therefore, a method of secondarily hydrogenating a resin for the purpose of reducing double bonds (for example, Japanese Patent Publication No. 55-41635, Japanese Patent Publication No. 45-17075,
54-20972, etc.) have also been carried out, and several types of hydrogenated petroleum resins have actually been put on the market. However,
The hydrogenation reaction of an aromatic petroleum resin generally requires harsh hydrogenation conditions, so that it is inevitably accompanied by the hydrogenation of a part of the aromatic ring. Therefore, an increase in manufacturing cost is unavoidable, and even if it is beneficial when used for special purposes, hydrogenation for the purpose of only improving heat resistance and weather resistance has the great advantage that petroleum resin is inexpensive. It is hard to say that it is an advantageous method.

From the above consideration of the conventional aromatic petroleum resin, the present inventors have found that in order to improve heat resistance and weather resistance, an aromatic compound having no double bond or containing no aromatic compound in practice is used. We have come to the conclusion that we have no choice but to radically consider the production method of petroleum-based resins.

(Means for Solving Problems) In order to produce an aromatic petroleum resin containing no double bond or containing no double bond practically by a method other than hydrogenation, it is practically necessary to use a raw oil as a raw material. It is necessary to use a feedstock that has no heavy bonds. The double bond as used herein does not include a double bond of an aromatic ring, and refers to a double bond in a side chain of an aromatic ring, a naphthene ring or paraffin. However,
It is generally impossible to polymerize an aromatic raw material having no double bond as it is, except for thermal reforming, etc., and the aromatic ring or the aromatic ring is separated from the aromatic ring by some method. It is necessary to add a binder for bonding the side chain of the aromatic compound or the side chains of the aromatic ring.

Thus, instead of using aromatic olefins as raw materials,
The idea of producing an aromatic hydrocarbon resin with an aromatic compound and a binder is a concept that has never been found in conventional aromatic petroleum resin production.

Therefore, the inventors of the present invention have combined a variety of aromatic raw materials and various binders to provide a new aromatic compound having physical properties (for example, a softening point of 60 to 180 ° C.) similar to those of conventional aromatic petroleum resins. The present invention has been achieved as a result of intensive research on a method for producing a petroleum-based resin. That is, formaldehyde is added to various aromatic raw materials having 1 to 4 side chains having a relatively small number of carbon atoms such as a methyl group and an ethyl group, as a binder for binding aromatic rings, and in the presence of an acid catalyst. To synthesize an aromatic methylene resin by performing an addition dehydration condensation reaction with
It was found that an aromatic petroleum resin having good heat resistance and weather resistance can be produced by separating a low boiling point fraction of an aromatic methylene resin obtained through catalyst separation and washing.

This resin is a linear oligomer in which an aromatic ring and a methylene group are alternately bonded, and has no double bond or practically contains no oxygen bond, and does not contain oxygen atom derived from formaldehyde at all or practically. It was found to be an aromatic hydrocarbon resin.

Here, having no double bond or containing no practical use indicates that the bromine number is 1.0 or less, and containing no oxygen atom or no practical use means that the oxygen atom is 1.0% by weight. Indicates the following.

It is a well-known fact that formaldehyde has a function of binding aromatic rings, and for example, a resin produced from meta-xylene and formaldehyde is put on the market under the general name of xylene resin. However, this xylene resin is a liquid resin containing a large amount of oxygen atoms in which the meta-xylene ring is bound by a methylene group, an ether group, an acetal group, etc., and is composed of only carbon and hydrogen and has no or virtually no oxygen atoms. It is essentially different from the general petroleum resin that does not contain it in its physical properties and uses. Further, the present inventors have found a method for producing an aromatic methylene resin from an aromatic compound and formaldehyde, which can be considered to contain no oxygen atom or practically few.
A patent application has already been filed (application number 60-054357).
However, this aromatic methylene resin is a viscous liquid or a semi-solid substance at room temperature, and a high softening point resin which is solid at room temperature cannot be produced. This is because when a solid high-softening point resin is produced at room temperature, the operation of removing a trace amount of acidic substances following catalyst separation becomes impossible due to the production of an emulsion.

As a result of thorough reexamination of the method for producing this aromatic methylene resin, the present invention shows that even if a solid high softening point resin is produced at room temperature, the catalyst is separated and the subsequent trace amount of acidic substance is removed. Of the aromatic petroleum resin, which is solid at room temperature and has excellent heat resistance and weather resistance. That is, it was found that the addition of an appropriate amount of alcohol suppresses the formation of an emulsion, and the oil layer containing a resin having a high softening point and the washing water can be easily separated.

(Operation) The aromatic raw material according to the present invention includes toluene, xylene,
Benzene derivatives such as ethylbenzene, methylethylbenzene, trimethylbenzene, durene, isodurene, etc., in which 1 to 4 substituents having a relatively small number of carbon atoms such as methyl groups or ethyl groups are substituted on the benzene ring, indane derivatives, naphthalene, anthracene, etc. There is no particular limitation as long as it is a derivative of various condensed polycyclic aromatic compounds, a mixture thereof, or a fraction containing a part thereof.

Even if an aromatic compound having a substituent having a relatively large number of carbon atoms such as a propyl group or a butyl group or a non-aromatic compound such as paraffin or naphthene is contained, these compounds are not reactive with formaldehyde. Since it is low or does not exist at all, it merely acts as a solvent, and the yield of the resin is apparently reduced, but there is no particular problem as long as the above-mentioned reactive aromatic compound is contained in the feed oil. However, it is necessary to consider the content of the reactive aromatic compound in the feedstock when determining the molar ratio of formaldehyde to the feedstock described below. Thus, generally, toluene, reforming-type or cracking-type mixed xylene fraction, C ₉ or C ₁₀ aromatic fraction obtained from bottom oil of xylene production or isomerization, etc. are practically preferable feedstocks. .

The formaldehyde according to the present invention may be in any form as a starting material as long as it produces a monomeric formaldehyde in the reaction system, and various commercially available concentrations of formalin or trioxane, and polymerized products such as paraformaldehyde. Etc. can be used as they are, but paraformaldehyde, which does not reduce the catalyst concentration (formalin reduces the catalyst concentration because it is an aqueous solution) and is easily available at a low price, is most suitable. Further, gaseous formaldehyde separately generated by some method may be dissolved in a raw material oil, a catalyst (if liquid), a solvent, etc. and charged into the reaction system.

The catalyst used in the present invention is not particularly limited as long as it is a liquid acid catalyst, and sulfuric acid, phosphoric acid, pyrophosphoric acid, perchloric acid or the like can be used. Further, paratoluenesulfonic acid, boron trifluoride, hydrogen fluoride, various aluminum chlorides and the like which are soluble in the raw material oil can be used, but these catalysts are difficult to reuse. Although it is possible in principle to use a solid acid catalyst, it cannot be said to be an industrially advantageous catalyst because it is necessary to use a large amount of diluting solvent in the catalyst separation step. Sulfuric acid is advantageous in that it is cheap and easy to reuse, and sulfuric acid of various concentrations can be used, but dilute sulfuric acid is most suitable for preventing sulfonation.

Since the present invention uses an excess amount of the raw material oil, no solvent is required, but if necessary, a solvent that does not participate in the reaction (eg, isoparaffin) can be added in an appropriate amount.

The petroleum resin reactor according to the present invention may be of a usual batch type, a semi-flow type, a flow type or the like regardless of the shape, but the batch type is the most practical.

In order to obtain the aromatic petroleum resin containing neither oxygen atom nor double bond of the present invention, it is necessary to control the molar ratio of formaldehyde to the reactive aromatic compound to 1 or less, preferably 0.8 or less. Generally, the lower the molar ratio, the lower the yield of the produced petroleum resin and the lower the softening point, depending on the type of aromatic compound used as the raw material, but the oxygen atom content under mild conditions. The higher the molar ratio, the higher the yield and the softening point, but the higher the oxygen atom content. Although it is possible to produce a petroleum resin even when the molar ratio is greater than 1, the content of oxygen atoms becomes high and the catalyst separation operation becomes difficult under the practical reaction conditions described below.

The amount of the catalyst used in this reaction cannot be unconditionally specified because it is closely related to the reaction conditions, but generally 5 to 50% by weight, preferably 15 to 50% by weight based on the reactive aromatic compound in the feed oil.
35% by weight is suitable.

The reaction temperature of this reaction cannot be specified unconditionally because it depends on the type and amount of feed oil and catalyst, but generally it is 60
~ 180 ° C, preferably 80-120 ° C is used.

The reaction time related to this reaction cannot be specified unconditionally because it depends on the type and amount of the feed oil and the catalyst, and the oxygen content of the petroleum resin produced decreases with the reaction time. Can be regarded as not containing at all,
It is generally 0.5 to 10 hours, preferably 2 to 5 hours.

In order to isolate the produced petroleum resin into a product, further removal of catalyst, washing (removal of trace acidic substances), unreacted oil, solvent (when used), and removal of light products are necessary. These can be implemented by the method described below.

Catalyst separation as it is or by adding an appropriate diluent solvent,
It can be carried out by a normal oil-water separation operation. The recovered catalyst is diluted with water produced during the reaction, but it can be reused as it is or by adding a high-concentration acid to adjust the concentration.

The washing step is an essential step for preventing the quality deterioration of the product due to the inclusion of a trace amount of acidic substance. Usually, a method of repeating neutralization treatment with an alkali and washing with water or washing with hot water is adopted, but as in the present invention, a petroleum resin having a high softening point,
When a trace amount of acidic substances and unreacted oil are present, an emulsion is formed and oil / water cannot be easily separated. If a large amount of solvent is newly added and diluted, oil-water separation becomes relatively easy, but it is necessary to dilute several tens of times, which is not practical.
Although a method of adding a commercially available emulsion breaker can be considered, it is not preferable because the emulsion breaker remains in the product and deteriorates the quality. Therefore, having a dissolving power of the generated petroleum resin, partially dissolves water, most of it remains in the oil layer in the oil-water separation step, and as a result of diligent study of an emulsion breaker that can be easily separated from the generated petroleum resin, It has been found that alcohols having 3 to 5 carbon atoms are suitable for the purpose. The discovery of this emulsion breaker is one of the factors leading to the success of the present invention. Here, the alcohol having 3 to 5 carbon atoms refers to all isomers of all alcohols having 3 to 5 carbon atoms or a mixture thereof.
Further, the purity of alcohol may be 50% by weight or more.
Preferably, n-butyl alcohol, iso-butyl alcohol and sec-butyl alcohol are used alone or as a mixture thereof.

The oil that has been washed with water contains alcohol, unreacted oil, and petroleum resin of the product. Therefore, in order to isolate the petroleum resin of the product, it is necessary to remove alcohol, unreacted oil, and light components of the produced petroleum resin. These removal operations can be performed in one step or in multiple steps. it can.

That is, adopt a multi-step operation in which alcohol and unreacted oil are removed simultaneously or separately by ordinary atmospheric distillation or operations such as an evaporator, and then only light components of the produced petroleum resin are removed by centrifugation, vacuum distillation, or the like. It is also possible to employ a one-step operation of gradually removing the light components having a boiling point or lower according to the required properties of the final product while gradually increasing the degree of pressure reduction using a normal vacuum distillation apparatus. In the end, it is necessary to remove light components up to what temperature
It cannot be unconditionally specified because it depends on the required properties of the target petroleum resin, but it is usually under a reduced pressure of 5 mmHg or less, preferably under a reduced pressure of 2 mmHg or less. By distilling off (including oil), the desired aromatic petroleum resin can be obtained in the bottom of the kettle.

(Examples) Examples are shown below to specifically clarify the content of the present invention, but this is an example and the present invention is not limited thereto.

In the practice, the softening point and bromine number of the produced aromatic petroleum resin were measured according to JISK-2207 and JISK-2605, respectively, and the oxygen content was measured by an elemental analyzer. Regarding the heat resistance of the petroleum resin, 50 g of the sample was placed in a glass container (30 mmφ × 100 mm) and aged in a gear oven at 150 ° C., and changes with time in appearance and viscosity were measured. For weather resistance, make a coating film of 80-90 μm on a glass plate and change the hue after exposure in a sunshine weatherometer under the conditions of temperature 63 ° C, humidity 60%, and rain for 120 minutes for 120 minutes. I observed.

Example 1 In a four-necked flask equipped with a stirrer and a reflux condenser, 240 g of a C ₉ aromatic fraction having a boiling point range of 150 to 180 ° C. of a reforming xylene column bottom oil and 20 g of a commercial industrial 92% paraformaldehyde.
And 75 g of commercially available 75% diluted sulfuric acid was added dropwise with slow stirring. After adding sulfuric acid, adjust the reaction temperature to 10 using an oil bath.
The temperature was raised to 0 to 110 ° C., and the reaction was continued for 3 hours with vigorous stirring. After completion of the reaction, the mixture was cooled to room temperature, and the contents were transferred to a dropping funnel and left to stand, so that a sulfuric acid layer was separated into a lower layer, which was removed. Then, add 100 ml of n-butanol and 200 ml of water, stir it well, and let it stand. The oil layer and the water layer are separated cleanly. Discard the water layer and continue washing with water 2-3 times until the pH of the washing water shows 7. Repeated. The obtained oil layer was transferred to a distillation flask, and first, vacuum distillation of about 10 mmHg was performed, and finally the pressure reduction degree was raised to 1 mmHg to remove light components below 460 ° C. at atmospheric pressure, and leave as a residue in the kettle. 112 g of aromatic petroleum resin was obtained. The softening point of the obtained petroleum resin is
117.5 ℃, Bromine number 0.3g Br ₂ / 100g, Oxygen content 0.1% by weight
Below, it became clear that practically neither oxygen atom nor double bond was contained.

The heat resistance and weather resistance of the obtained petroleum resin are shown in Table 1 and Table 2, respectively.

Example 2 After using the same apparatus as in Example 1 and carrying out reaction and catalyst removal / water washing under the same feed oil and under the same conditions, finally, a light component under atmospheric pressure conversion of 360 ° C. or lower was distilled off under a reduced pressure of 1 mmHg. Then, 134 g of a target aromatic petroleum resin was obtained. The resulting softening point of the petroleum resin is 88.5 ° C., bromine number is 0.2gBr ₂ / 100g, oxygen Motoritsu was 0.1% by weight or less. Table 1 and 2 for heat resistance and weather resistance
Shown in.

Example 3 Using the same apparatus as in Example 1 and using 240 g of xylene fraction as a raw material under the same conditions as in Example 1, the reaction, catalyst removal and water washing were carried out, and then a light fraction at 450 ° C. at atmospheric pressure equivalent or lower was obtained. After removal by distillation under reduced pressure, 98.2 g of the desired aromatic petroleum resin was obtained. The resulting softening point of the petroleum resin is 92.0 ° C., bromine number is 0.2gBr ₂ / 100g, oxygen Motoritsu was 0.1% by weight or less.
The heat resistance and weather resistance are shown in Tables 1 and 2.

Example 4 The same equipment as in Example 1 was used, and a reforming xylene bottom oil was used.
After 240 g of a C ₁₀ aromatic fraction having a boiling range of 0 to 200 ° C. was used as a raw material, the reaction, the catalyst removal and the washing with water were carried out under the same conditions as in Example 1, and then the light components at a normal pressure of 460 ° C. or less were decompressed. When it was removed by distillation, 102 g of the target aromatic petroleum resin was obtained. The petroleum resin obtained has a softening point of 124.5 ° C and a bromine number of
0.1gBr ₂ / 100g, the oxygen content was less than 0.1% by weight. The heat resistance and weather resistance are shown in Tables 1 and 2.

Example 5 The same apparatus as in Example 1 was used, and commercially available 70
% 75% of perchloric acid was used to react with the same raw material oil as in Example 1 under the same conditions, and after removing the catalyst and washing with water, vacuum distillation was carried out under the same conditions to obtain the desired aromatic petroleum resin. 123 g were obtained. The softening point of the obtained petroleum resin is 120.
5 ° C., bromine number is 0.2gBr ₂ / 100g, oxygen Motoritsu was 0.3 wt%. The heat resistance and weather resistance are shown in Tables 1 and 2.

Example 6 After using the same apparatus as in Example 1 and performing reaction and catalyst removal under the same feed oil and under the same conditions, 80 ml of sec-butanol and i
When 20 ml of so-propanol and then 200 ml of washing water were added and stirred well and left to stand, the water layer and the oil layer were separated cleanly, so the water layer was discarded, and the water washing was repeated three more times. As a result of removing light components from the obtained oil layer by the same operation as in Example 1, 109 g of a target aromatic petroleum resin was obtained. The resulting softening point of the petroleum resin is 119.5 ° C., bromine number is 0.1gBr _2/100
g, oxygen content was 0.1% by weight or less. The heat resistance and weather resistance are shown in Tables 1 and 2.

Comparative Example 1 As a representative of conventional aromatic petroleum resins, a commercially available C ₉ petroleum resin (120 grade) was selected.

Softening point is 122.0 ℃, bromine number 28.0g Br ₂ / 100g, oxygen content 2.0
% By weight. Heat resistance and weather resistance are shown in Table 1 and Table 2, respectively.
Shown in.

Comparative Example 2 Using the same apparatus as in Example 1, after performing reaction and catalyst removal under the same feed oil and under the same conditions, 200 ml of washing water was added for the purpose of removing a trace amount of acidic substances, and the mixture was allowed to stand by stirring well. However, even if it was left to stand overnight or more, an emulsion was formed mainly on the oil / water interface, and it was impossible to carry out the oil / water separation operation.

(Effects of the Invention) From the results shown in Table 1, the aromatic petroleum resin obtained according to the present invention is more gradual in hue change and viscosity increase than the conventional aromatic petroleum resin, and is significantly excellent in heat resistance. It is understood that there is. Further, from the results of Table 2, it is clear that the aromatic petroleum resin obtained according to the present invention has a gentler hue change as compared with the conventional aromatic petroleum resin, and the weather resistance is remarkably improved. is there.

The aromatic petroleum resin obtained by the present invention can be basically used for the same purpose as conventional petroleum resins, but it is required to have high heat resistance and high weather resistance, such as traffic paint and hot melt adhesive. It can be used more suitably. In addition, since these applications often include a heating and melting step, it has a great effect on improving workability.

Claims (10)

[Claims] 1. An aromatic methylene resin is synthesized by reacting an aromatic compound or a fraction containing an aromatic compound as a main component with formaldehyde in the presence of an acid catalyst, and the catalyst is removed by an oil / water separation operation to obtain a purity of 50. A process for producing an aromatic petroleum resin, which is produced by adding at least 5% by weight of an alcohol having 3 to 5 carbon atoms and washing with water, and then removing the low boiling point fraction. 2. The process for producing an aromatic petroleum resin according to claim 1, wherein paraformaldehyde is used as formaldehyde and sulfuric acid is used as a catalyst. 3. An aromatic compound or a fraction containing an aromatic compound as a main component, toluene, a reformed or decomposed mixed xylene fraction, or a C ₉ obtained from a bottom oil for xylene production or isomerization. Alternatively, the method for producing an aromatic petroleum resin according to claim 1, wherein a C ₁₀ aromatic fraction is used. 4. The aromatic petroleum resin according to claim 1, wherein the alcohol having 3 to 5 carbon atoms is n-butyl alcohol, iso-butyl alcohol, sec-butyl alcohol alone or a mixture thereof. Manufacturing method. 5. The method for producing an aromatic petroleum resin according to claim 1, wherein a vacuum distillation apparatus is used as a method for removing the low boiling point fraction. 6. The method for producing an aromatic petroleum resin according to claim 1, wherein the amount of formaldehyde with respect to the reactive aromatic compound is smaller than its chemical equivalent. 7. The method for producing an aromatic petroleum resin according to claim 1, wherein the amount of formaldehyde with respect to the reactive aromatic compound is 0.8 or less of its chemical equivalent. 8. A reaction temperature of 60 to 180 ° C. and a reaction time of 0.5 to 10
The method for producing an aromatic petroleum resin according to claim 1, which is time. 9. A reaction temperature of 80 to 120 ° C. and a reaction time of 2 to 5
The method for producing an aromatic petroleum resin according to claim 1, which is time. 10. The method for producing an aromatic petroleum resin according to claim 2, wherein the amount of sulfuric acid is 5 to 50% by weight based on the reactive aromatic compound.