AROMATIC HIGH SOFTENING POINT PETROLEUM RESIN AND PROCESS FOR ITS PREPARATION

Abstract: High softening point, i.e. greater than 140°C, aromatic petroleum resins are prepared by polymerizing with an AlCl₃ catalyst an unsaturated hydrocarbon mixture of one part of (1) a feedstock fraction obtained from the thermal cracking of petroleum boiling in the range of 135-220°C and principally composed of aromatic substituted olefins, e.g. styrene and its derivatives and indenes and its derivatives and from 0.3 to 1 part by weight of (2) oligomers of cyclo­ pentadiene.

Description: This invention relates to hydrocarbon resins and processes for their preparation. More particularly, the in­ vention relates to high softening point hydrocarbon resins prepared by polymerizing a mixture of a hydrocarbon fraction comprised of aromatic olefins and oligomers of cyclopenta­ dienes by means of aluminum chloride catalyst. The polymer­ ized resin is then quenched, washed to remove catalyst residues and finished to provide high softening point hydro­ carbon resins. BACKGROUND OF THE INVENTION Hydrocarbon resins can be produced from certain petroleum refinery streams containing mixtures of olefins and diolefins by polymerization using Friedel-Crafts cata­ lysts. The steam cracked streams have been found especial­ ly useful for this purpose. For example, heavier petroleum fractions such as naphtha, gas oil, and the like, are steam cracked and the gas and liquid streams so produced contain large quantities of diolefins and olefins in the C₅ and C₁₀ range. The naphtha distillate streams obtained by steam cracking operations, boiling in the range of 30 to 300°C., contain large amounts of diolefins, olefins and aromatics. The resins produced from these streams generally have soft­ ening points much lower than desired for certain applica­ tions, such as, for example, offset ink printing which requires softening points of about 140°C. The manufacture of hydrocarbon resins having a softening point of 140° C. or above is disclosed in several U.S. Patents including U.S. Patent No.2,753,326 (Aug. 3, 1958). In the process, a thermal cracked petroleum fraction with boiling range of 80-280°F. is heat treated at 300°F. to dimerize, and this dimerized fraction is treated at 400-­ 700°F. to decompose cyclic diolefin dimer into monomer, while the aliphatic diolefin dimer fraction is not cracked and is polymerized using a Friedel-Crafts catalyst. According to the examples of the reference, the resins obtained are such that the maximum softening point is 160°C. In U.S. 3,753,963, resins having softening points of 115 to 158°C are reported as being prepared from a feedstock comprises of styrene and its derivates, and indene and its derivates. To prepare the high softening point resin, (i.e. 140°C.) the styrene content is adjusted to below 7 wt. percent and the total content of indene and its alkyl derivates is adjusted to above 5 wt. percent. Phenols and alkylphenols are added to the feed at 0,5 to 5 wt. percent and the polymerization is conducted using boron trifluoride type catalyst such as gaseous boron trifluoride or complexes of boron trifluoride. Other approaches to the preparation of such high softening point petroleum resins includes: thermaly polymerization cyclic diolefins such as cyclopentadiene or blends of these cyclic diofelins with aliphatic and/or aromatic substituted olefins and diolefins, such as 1,3-pentadiene or styrene; and, polymerizing aromatic substituted olefins such as blends of styrene, α-methyl styrene, vinyl toluene, indene and methyl indenes, using a Friedel-Craft catalyst such as BF₃. Unfortunately, the polymerization of such an aromatic substituted olefinic feed in a continuous reactor using AlCl₃ as the catalyst, does not yield a resin having a softening point as hogh as 140°C., i.e. the softening point is 125 to 130°C. STATEMENT OF THE INVENTION It has been discovered that petroleum resins having a softening point of at least 140°C can be produced in a continuous polymerization by means of an aluminium chloride catalyst when tne polymerization mixture is composed of 0,4 parts by weight of cyclopentediene oligomers and one part by weight of an aromatic olefinic fraction having a boiling range of from 135 to 220°C. Therefore, in accordance with this invention there is realized a high softening point petroleum resin prepared by a process which comprises polymerizing in the presence of a least a catalyst amount of aluminium chloride an unsatured hydrocarbon mixture of one part by weight of (1) an aromatic substituted olefinic feedstock having a boiling range of from 135 to 220°C and composed of styrene and its derivates and indene and its derivates and from 0.3 to 1 part by weight of (2) dimers and codimers of cyclopentadiene and alkylcyclopendiene washing the polymerization hydrocarbon mixture with aqueous isopropanol solution, and finishing the polymerizate. The petroleum resin have a softening point of 140°C to 160°C. Tredimers and codimers are sometimes referred to herein as being part of the oligomer stream. DETAILED DESCRIPTION OF THE INVENTION As set forth above the high softening point resins are obtainable by a process which comprises polymerizing with an aluminium chloride catalyst a mixture of one part of an aromatic feedstock with a mixture of diclopentadiene, an alkyl cyclopentadiene dimer, a codimer of cyclopentadiene with an alkyl cyclopentadiene, a codimer of cyclopentadiene or an alkyl cyclopentadiene with a C₄ to C₆ acyclic olefins and diolefins or a mixture of said dimers and codimers. These dimers and codimers are produced during the thermal Diels Alder reaction of feedstocks containing conjugated cyclic diolefin and acyclic C₄ to C₆ olefins and diolefins, as for example cyclopentadiene and alkyl cyclopentadiene as well as isoprene or pentadienes-1,3. The vinyl aromatic feedstock has a composition which is 3 to 10 wt.% styrene, 2 to 6 wt.% α-methyl styrene, 15 to 25 wt.% vinyl toluene, D to 18 wt.% indene and 4 to 12 wt.% methyl indene, thus it be described as containing styrene and its derivates and indene and its derivates and is obtained by steam cracing petroleum refinery streams and separating the fraction boiling in the range of 135 and 220°C. The second component of the mixture to be polymerized are the dimers and codimers of cyclopentadiene and alkyl cyclopentadienes as well as the codimer of each of these with acyclic C₄ to C₆ olefins and diolefins. The dimers or codimers are obtained from the heat scaking process mentioned above. Usually, the alkyl cyclopentadiene is methyl cyclopentadiene and usually this stream comprises both dicyclopentadiene and methylcyclopentadiene dimer which are formed by thermal oligomerization. This stream which is subjected to thermal oligomerization, usually has a boiling range of from 20° to 220°, e.g. 30 to 180°C. The oligomer containing stream comprises the follow­ ing: a 0.5 to 6 wt.% butadiene-cyclopentadiene codimer, 2 to 8 wt.% isoprene-cyclopentadiene codimer, 25 to 40 wt.% dicyolopentadiene,3 to 10 wt.% piperylene cyclopentadiene codimer, 25 to 40 wt.% cyclopentadiene methylcyclopenta­ diene codimer and 2 to 8 wt.% methylcyclopentadiene dimer. The two components of the mixture, i.e. the aro­ matic feedstock and the oligomer containing stream when copolymerized may provide polymers having vinyl aromatics/indenes/cyclic dimers, co­ dimers molar ratios ranging from 0.5/0.4/1 to 3/3/1, respectively. Preferably the feed weight ratios vary from 1:4 and 1:2, which provide polymers having vinyl aromat­ ics/indenes/cyclic dimers, codimers molar ratios ranging from 1.4/1.9/1.0 to 1.0/0.8/1.0, respectively. The resin feedstock mixture may be polymerized in a conventional manner with conventional aluminium chloride catalyst. The polymerizations can be run either batch wise or continuous. It is also advantageous to use a non-reactive dil­ uent in the reactor to reduce the polimerizate viscosity and minimize the sludge build-up on the reactor walls. The diluent can be used in concentrations of 0 to 30%, but preferably 10%, by weight. In one optionusing batch runs the aluminum trichloride is added to the stirred resin feedstock under an inert atmosphere. The catalyst concentrations are conveniently in the range 0.2 to 5 weight percent and preferably 0.3 to 1.7 weight percent based on the resin feedstock. The resin feedstock is adjusted to the polymerization temperature of 0 to 60°C. and maintained at that temperature the prescribed length of time. The preferred conditions using aluminium chloride as the cata­ lyst is 1.0 percent catalyst for a reaction temperature of 40°C for a period of 1 to 2 hours. In another option using continuous runs, catalyst and resin feedstock are added to a stirred reactor maintained at the polymerization temperature under an inert atmosphere. The concentration of aluminium chloride catalyst is conveniently in the range of 0.3 to 3 and preferably 0.7 to 1.25 by weight with the temperatures of the reactor at 0 to 60°C. The most suitable feed addition rate gives an approximate residence time of 0.3 to 2.0 hours. The resultant resin mixture is then quenched with an aqueous isopropanol solution to destroy the catalyst washed and finished to produce a high softening point resin of from 140°C to 160°C. Although the specific range in feedstock composition of 0.3-1 : 1, taught to be highly useful in the process of the invention, one skilled in the art can most likely expand it by the appropriate combination of feedstock ratio, feed diluent catalyst concentration, reaction temperature and residence time. This high softening point resin may be emulsified by dissolving it in a hydrocarbon solvent such as toluene, and adding this mixture to water containing an emulsifier, such as an alkylaryl polyether alcohol. The resultant emulsion may than be stripped to remove the solvent. The invention can be further illustrated by the following examples, although it will be understood that these examples are included merely for purposes of illustration and are not intensed to limit the scope of the invention unless otherwise specifically indicated. EXAMPLE 1 The cyclopentadiene oligomeric stream set out in Table 1 and the aro­ matic stream shown on Table 1 are blended in a 1 : 1 ratio and diluted by 10% with a mixture of non-reactive hydrocarbons. This feed blend is continuously pumped into the reactor under a nitrogen blanket, thoroughly agitated, and held at a temper­ ature of 45°C. The AlCl 3 catalyst is continuously added to the reactor at a 1.0% level based on the weight of the feedstock. The catalyst in the reactor polymerizate is quenched in a water-isopropanol solution and the polymerizate is subsequently washed with water. The resin is finished by steam stripping at 250°C. The finished resin softening point was 155°C and the Gardner color was 14 1/2. EXAMPLE 2 The cyclopentadiene oligomeric stream and the aro­ matic stream shown on Table 2 are blended in a 1 : 2 ratio and diluted as described in example 1. This continuous reaction is run at 50°C. and the catalyst concentration is 0.7% based on the weight of the feed. After quenching, washing and finishing as describeb in example 1, the re­ sultant resin had a softening point of 142°C and a Gardner color of 13. EXAMPLE 3 The high softening point resin is emulsified by dissolving 140 grams of it in 75 grams of toluene and mixing this solution with a solution of 215 grams water and 7 grams of Triton X-100, using a Silverson heavy duty laboratory mixer emulsifier. The mixer is run at full speed while the resin/toluene solution is slowly added to the water/emulsi­ fier solution and is run an additional 10 minutes after the resin toluene solution is added. The container in which the mixing is being done is kept in an ice bath during the mixing to hold the temperature at about 35°C and below 40°C. The subsequent emulsion is vacuum stripped using a rotory stripper at about 65°C. The resultant emulsion had a solids content of 59.1% and an average particle size of 1 to 2 microns.

Claims: 1. A process for preparing a high softening point resin which comprises polymerising in the presence of at least a catalytic amount of aluminum chloride, an unsaturated hydrocarbon mixture characterised in that the mixture comprises one part by weight of (1) an aromatic substituted olefinic feedstock having a boiling range of from 135 to 220°C and composed of styrene and its derivatives and indene and its derivates and from 0.3 to 1 part by weight of (2) dimers and codimers of cyclopentadiene and alkyl cyclopentadiene as well as the codimers of each of these with acyclic C₄ to C₆ olefins or diolefins and the polymerization temperature ranges from 0 to 60°C. 2. A process according to claim 1 wherein there is present up to 30% by Weight based on the total weight of the feedstock non-reactive diluent. 3. The process according to claim 1 wherein said aromatic feedstock includes from 3% to 10% styrene, from 2% to 6% alpha methyl styrene, from 15% to 25% vinyl toluene, from 10% to 18% indene and from 4% to 12% methyl indenes. 4. The process according to claim 3 wherein said oligomers of cyclopentadiene comprises 0.5 to 6 wt% butadienecylcopentadiene, 2 to 8 wt% isoprene-cylcopentadiene codimer, 25 to 40 wt% dicyclopentadiene, 3 to 10 wt% piperylenecyclopentadiene codimer, 25 to 40 wt% cyclopentadiene-methyl-cyclopentadiene codimer, and 2 to 8 wt% methylcyclopentadiene dimer. 5. The process according to claim 4 wherein said aluminum chloride concentration ranges from 0.3 to 3.0 wt% based on the total weight of the mixture and the polymerisation temperature ranges from 0 to 60° C. 6. The process according to claim 5 wherein the polymerisation is continuous with a reaction residence time of from 0.5 to 2 hours. 7. The process according to claim 4 wherein the polymerisation is batch and the aluminum chloride concentration ranges from 0.2 to 5.0 wt% based on the total weight of the feedstock, non-reactive diluent concentration of 0-30%, and the polymerisation temperature ranges from 0 to 60°C and is maintained for a period of 1 to 2 hours. 8. A resin having a softening point of 140°C to 160°C obtainable by a process which comprises polymerising in the presence of at least a catalytic amount of aluminum chloride, an unsaturated hydrocarbon mixture of one part by weight of (1) an aromatic substituted olefinic feedstock having a boiling range of from 135 to 220°C and composed of styrene and its derivatives and indene and its derivatives and from 0.3 to 1 part by weight of (2) dimers and codimers of cyclopentadiene and alkyl cyclopentadiene as well as the codimers of each of these with acyclic C₄ to C₆ olefins or diolefins, quenching said polymerised hydrocarbon mixture with a water/-isopropanol solution washing said polymerised hydrocarbon with water and finished washed polymerisate to provide the petroleum resin.

Inventors: EVANS, MORRIS LEE, SMALL, AUGUSTUS BAILEY
Applicants: EXXON RESEARCH AND ENGINEERING COMPANY
Application year: 1985
Main classification: C08F240
IPC codes: C08F240