Issue 15/2012 - C9 Advances in petroleum resin production technology

First, the production technology of C9 petroleum resin

At present, there are three main methods for producing ordinary petroleum resin by cracking C9 fractions: catalytic polymerization, thermal polymerization and radical initiation polymerization
.
These three methods have their own advantages and disadvantages, and the technical route can be selected according to the composition of raw materials, product use and factory conditions, and can also be aggregated
in segments.

Large foreign companies have applied for a large number of patents in the research field of C9 petroleum resin, and the famous patentees include Exxon Company of the United States, Amoco Company, Dow Chemical; Japan's Mitsui Petrochemical, Tosoh, Toho Chemicals; BASF in Western Europe, etc
.
Most of the foreign technologies focus on process improvement, catalyst use, resin modification, and the use of different fractions
.
Aliev Sahib et al.
proposed the synthesis of C9 petroleum resin by continuous thermopolymerization; MoNagahara Eiji et al.
proposed that in order to facilitate the hydrotreatment of resin and prepare high-performance resins, AlCl3 or BF3 should not be complexed with phenolic substances or substances containing hydroxyl groups in molecules; American researchers proposed that C9 separates raw materials and uses 150~220 °C fraction catalytic polymerization as an additive
for the production of hot melt adhesive.

The research of domestic C9 petroleum resin started late, but developed rapidly, many of which have been industrialized, and the research direction is mainly focused on process improvement and catalyst development
.
Hubei Xiangfan Chemical Industry Research Institute, Daqing Petroleum Institute, Daqing Petrochemical Plant Research Institute, Nanjing University, Shandong Building Materials Institute, etc.
have been engaged in the research of
C9 aromatic petroleum resin.

The high activity of dicyclopentadiene (DCPD) in the pyrolysis C9 fraction is the main factor affecting the resin hue, which is generally required to be no more than 2% abroad, while the DCPD content in China's C9 component is higher
。 To this end, Hubei Xiangfan Chemical Industry Research Institute studied the two-stage polymerization method and the two-stage polymerization method, that is, when the DCPD content in cracking C9 < 15%, the two-stage polymerization method was used, and the catalyst was gradually dropped in the front section with a lower reaction temperature, so that the highly active monomer was gradually polymerized first, and to a certain extent, the reaction temperature was increased for post-stage polymerization, which could not only avoid the formation of gel substances, but also improve the resin yield, and the resin chromaticity was lighter than the<b111> one-step method No.
2~3 。 When the DCPD content in the raw material > 15%, a two-time polymerization process is adopted, that is, in the presence of a very small amount of catalyst, the DCPD with higher activity is selectively polymerized and separated, and the fraction with very low DCPD content is washed by oil hot boiling water to remove the catalyst
in the prepolymerized resin.
Then distillation cutting, the front distillation is divided into styrene and mixed methyl styrene, the back distillation is divided into indene and methyl indene, which can be secondary polymerized to obtain two different resins, which are secondary polymerization resins
with light color, high softening point, water resistance, corrosion resistance, heat resistance, aging resistance and other excellent properties.

The Petrochemical Technology Development Center of Tianjin University has carried out new development research on the production of C9 petroleum resin by thermal polymerization, which overcomes the shortcomings
of dark hue and low grade of petroleum resin.
The new process uses C9 fractions with high DCPD content to carry out three operation steps: raw material separation, continuous thermal polymerization, and solvent removal, without catalyst and no wastewater treatment
.
In the light-colored resin is obtained at the same time to obtain high-quality aromatic solvent oil
.
The technology has been built in 2002 in Qilu Petrochemical Group Co.
, Ltd.
10,000-ton petroleum resin plant, its thermopolymerization resin chromaticity is below No.
10, softening point 110~140 °C, comonomer yield up to 95%.


The research institute of Daqing Petrochemical Plant has studied the two-step synthesis process of free radical method and cation method, and the total yield of petroleum resin has been increased to more than
60%.
The process uses terminators and filtration removal catalysts to replace the traditional alkali washing and water washing methods, avoiding the problem
of environmental pollution caused by emulsification and a large amount of fluorinated wastewater.
The dark petroleum resin produced by this method has good miscibility, the light color of the petroleum resin is less than 8, and the softening point is greater than 120 °C, and the technology has been successfully
tested.

Daqing Petroleum Institute uses Daqing ethylene plant to crack C9 distillate as raw material, anhydrous aluminum trichloride as catalyst to synthesize oil-soluble C9 resin
.
The optimal reaction conditions are: catalyst dosage 0.
02%, polymerization temperature 35 °C, polymerization time 2 hours, light yellow resin can be obtained, and the catalyst is removed by alcohol washing, which basically solves the problem
of three wastes in production.

Nanjing University studied the synthesis of C9 petroleum resin
by radical polymerization and solid acid catalytic synthesis.
The influence of various initiators and their composition, dosage and reaction time on the polymerization reaction was discussed, tert-butanol peroxide/sodium oleate (mass ratio of 10:1) was used as the initiator, the amount added was 1.
5%, the reaction temperature was 160~170 °C, and the reaction time was 15 hours, liquid C9 petroleum resin could be obtained without post-treatment, and more than 50% of the polymer could be converted, and the color of the product was 14
~15.

Hengshui Normal College carried out the synthesis research of styrene-indene resin, the process of fractionation of C9 raw materials, obtaining effective active components and then decolorization, and then selecting high-efficiency catalysts for polymerization, through washing, vacuum distillation to obtain styrene-indene resin, the hue and softening point of the product reached international standards
.
The product is an excellent rubber tackifier and softener, after adding can improve the viscosity, strength and ductility of rubber, is the production of tires auxiliaries, at present there is no production factory in China, the product all rely on imports
.

Second, the modification of C9 petroleum resin

1
.
The introduction of polar group
petroleum resin introduces polar groups, which can improve the compatibility and dispersibility with polar compounds, and the product can be widely used as a water quality stabilizer and thickener in oilfields and chemical production.

Hubei Xiangfan Chemical Industry Research Institute uses C9 petroleum resin and 5%~20% maleic anhydride at 180~200 °C for 3~5 hours, the acid value of petroleum resin (in terms of KOH) can be increased from the original <1mg/g to more than 100mg/g, and the softening point can be increased by 20~40 °C
.

Tianjin Silicate Products Factory emulsifies C9 resin to make an emulsion for the production of coatings, adhesives, etc.
, by first breaking C9 resin, adding solvent according to the proportion, dissolving at about 40 °C, and then adding emulsifier, water dispersant, emulsion stabilizer
.

Daqing Petroleum Institute in the cracking C9 introduced polar group-acrylamide (AM), synthesis of C9-AM water-soluble petroleum resin, because of the cracking C9 rich in unsaturated bonds, easy to copolymerization reaction, can use this characteristic to make it react with active monomer, such as copolymerization with acrylamide to obtain water-soluble products, it can be used as water quality stabilizer and thickener and other products, widely used in
oilfield and chemical production 。 The method is to configure C9, AM and acetone reaction solution in a certain proportion, heat to 60 °C, add initiator, carry out free radical polymerization, and obtain copolymer as modified resin
by separation, washing and drying.

Domestic researchers use part of the double bond contained in the molecular chain of C9 petroleum resin, select soft butyl acrylate monomer to graft and modify, the introduction of flexible acrylate branched chain plays an internal plasticizing effect, and the acrylic polymer itself has excellent weather resistance and corrosion resistance, the modified petroleum resin can be made into anti-corrosion coatings with good performance, and the amount of butyl acrylate is appropriate
to 12%.

2.
The C9 petroleum resin obtained by hydromodified
polymerization reaction is generally darker in color and poor in thermal stability, and the presence of double bonds and benzene rings affects the color, stability and compatibility with other resins of the resin, limiting the scope
of application 。 Through catalytic hydrogenation, it can destroy the unsaturated double bonds in the resin, and remove the halides left in the polymerization process of the resin, improve its hue and photothermal stability, and improve the compatibility and weather resistance with other resins, so in recent years, developed countries have focused on the development of hydrogenated petroleum resins, and researchers have done a lot of work
on hydrogenation processes, catalysts and solvent selection.

Due to the large molecular weight of C9 petroleum resin, the polymer molecules stretch on the surface of the catalyst, forming a high steric hindrance, making the reaction strip harsh, and its hydrogenation process mainly includes slurry, fixed bed, spray tower three methods
.
These processes generally use nickel- or palladium-loaded single-metal catalysts, and the carrier is generally diatomaceous earth
.
The reaction temperature is generally 200~300 °C, the pressure is 3~10Mpa, and the solvents used are n-heptane, cyclohexane and mineral oil with poor solubility
.

In order to improve the performance of C9 petroleum resin, Daqing Petrochemical Research Institute studied the fixed-bed hydrogenation process and obtained water-white hydrogenation C9 petroleum resin
with excellent thermal stability 。 The institute uses C9 petroleum resin (bromine price of 20.
6g/100g, thermal stability greater than 18) produced by Anshan Chemical No.
1 Plant as raw material, uses S105 high-efficiency solvent to dissolve the solid resin, and then enters the polymetallic catalyst (PC-4) reactor equipped with nickel loading, the reaction temperature is generally 270 °C, the pressure is 5.
0~6.
0Mpa, the resin mass airspeed is 0.
15h-1, and the solvent is recycled after distillation
.
After hydrogenation, the resin softening point is greater than 90 °C, hue 30, and all indicators have reached or exceeded the level of ESC-OREZ5380 products in
the United States.

Domestic demand for hydrogenated C9 petroleum resin is increasing year by year, research work is also carried out, has made some progress, but compared with foreign products and modification of the pertinence is poor, so far there is no hydrogenation C9 petroleum resin production plant in China, to meet the demand is still all dependent on imports, further development of such research work will be promising
.