JP6515645B2 - Method for producing polybutylene ether di (meth) acrylate - Google Patents

Description

  The present invention relates to a process for the preparation of polybutylene ether di (meth) acrylates. More specifically, the present invention relates to a process for producing polybutylene ether di (meth) acrylate by ring-opening polymerization of tetrahydrofuran (hereinafter sometimes abbreviated as "THF") in the presence of a solid acid catalyst and anhydrous (meth) acrylic acid .

  Polybutylene ether di (meth) acrylate is used for soft segments such as polymethacrylate resin. Various methods have hitherto been disclosed for producing polybutylene ether di (meth) acrylate.

For example, ring-opening polymerization of THF in the presence of a strong acid such as HSbF ₆ or trifluoromethanesulfonic acid and anhydride (meth) acrylic acid (Patent Document 1), a strong acid such as HSbF ₆ or trifluoromethanesulfonic acid and transesterification A method of using a catalyst in combination and performing ring-opening polymerization in the presence of anhydrous (meth) acrylic acid (Patent Document 2), ring-opening polymerizing THF in the presence of trifluoromethanesulfonic acid anhydride to obtain triflate, and then sodium methacrylate (1), polybutylene ether glycol (also referred to as polytetramethylene ether glycol: hereinafter sometimes abbreviated as "PTMG") and produced by transesterification of anhydrous (meth) acrylic acid There is a method (patent document 3).

Japanese Patent Application Laid-Open No. 56-125428 Japanese Patent Application Laid-Open No. 58-176213 JP, 2012-12551, A

European Polymer Journal 38 (2002) 1591-1599

  However, in the methods shown in Patent Documents 1 to 3, the reaction vessel is required to be highly corrosive because any expensive strong acid and / or strong acid anhydride is used. In addition, it is difficult to recycle strong acids and / or strong acid anhydrides, and a large amount of waste acid must be treated, resulting in large cost load and not industrially effective. Further, the method disclosed in Patent Document 2 generates a large amount of a mixture of an inorganic acid and an organic acid as a waste acid, and therefore the load of wastewater treatment becomes large. The method disclosed in Non-Patent Document 1 involves a two-step reaction, which complicates the reaction operation. Furthermore, since the molecular weight of the polybutylene ether di (meth) acrylate obtained depends on the molecular weight of PTMG as a raw material, and the type of PTMG available is limited, the method disclosed in Patent Document 3 has a poly It has the disadvantage that the molecular weight of butylene ether di (meth) acrylate can not be arbitrarily changed.

  Accordingly, an object of the present invention is to provide a method for producing polybutylene ether di (meth) acrylate in which the amount of waste acid is small, the catalyst can be reused, and the molecular weight can be easily controlled. That is, the present invention is a method for producing polybutylene ether di (meth) acrylate by ring-opening polymerization of tetrahydrofuran in the presence of a solid acid catalyst and anhydrous (meth) acrylic acid.

  According to the present invention, it is possible to produce a polybutylene ether di (meth) acrylate having a small amount of waste acid, to easily reuse the catalyst after the reaction, and to control the molecular weight.

Hereinafter, embodiments of the present invention will be described in detail.
The solid acid catalyst used in the present invention is not particularly limited, and examples thereof include ion exchange resin, activated clay, acid clay, heteropolyacid, zeolite, silica alumina and the like. Examples of the ion exchange resin include fluorine-based strongly acidic ion exchange resins such as "Nafion" developed by DuPont. The acid clay is a white clay mainly composed of montmorillonite, which exhibits acidity due to the base unsaturation of the clay particles themselves. Activated clay is an acid-treated clay mineral to enhance its adsorption ability and decolorization ability. Examples of solid acids comprising activated white clay and acid white clay used in the present invention include activated white clay obtained by acid treatment of montmorillonite clay, and natural acid white clay such as fuller's earth and Florida's earth. The solid acid catalyst is preferably superacidic. The index relating to acidity includes numerical values such as acidity (mg KOH / g) and pH (5% by mass suspension). The acidity is preferably 0.8 or more, more preferably 1.0 or more. The pH is preferably 4 or less, more preferably 3.5 or less.

  These solid acid catalysts are easy to separate. Among them, activated clay is preferable in terms of both price and availability.

  Since the ring-opening polymerization reaction of THF in the present invention essentially has the property of being suppressed by water, it is preferable that THF, anhydrous (meth) acrylic acid, solid acid catalyst and the like used do not contain water. In addition, (meth) acrylic acid is a general term for methacrylic acid and acrylic acid, and (meth) acrylate is a general term for methacrylate and acrylate. When water is contained in these, for example, if it is THF or anhydrous (meth) acrylic acid, it is a solid acid catalyst by distillation purification, azeotropic dehydration purification, heat drying, dehydration with a dehydrating agent, etc. It is preferable to remove water before being subjected to the ring-opening polymerization reaction by heat drying, baking, treatment with a dehydrating agent, evaporation drying method, spray drying method, freeze drying method, vacuum drying method or the like. The drying conditions for heat drying are usually 50 to 500 ° C, preferably 100 to 400 ° C. The drying time is usually 0.5 to 100 hours, preferably 1 to 30 hours. The drying is generally performed in an oxygen-containing gas atmosphere such as air, but may be performed in an inert gas atmosphere such as nitrogen, argon, helium or in vacuum.

  The reaction conditions vary depending on the molecular weight of the target polybutylene ether di (meth) acrylate and the type of acid catalyst used, but the solid acid catalyst is usually 0.001 to 100 times by mass, preferably 0 times the liquid phase. .005 to 20 mass times are used. If the amount of the catalyst is too small, the polymerization reaction will be slow, and if it is too large, removal of the heat of polymerization will be difficult, and the slurry concentration in the reaction system will be high and stirring will be difficult. Are also prone to problems.

  The reaction can be carried out batchwise or continuously. When carrying out by a batch system, it is preferable to carry out reaction, stirring THF and an anhydrous (meth) acrylic acid and a solid acid catalyst, respectively to a reactor, and stirring. After completion of the reaction, the catalyst and the reactant are separated. In the case of the continuous system, the raw materials THF and anhydrous (meth) acrylic acid are continuously introduced into a reactor containing a solid acid catalyst and reacted, and the reaction liquid is continuously withdrawn from the reactor. Well, any of the suspension bed method and the fixed bed flow method can be performed. In the case of the suspension bed system, it is possible to additionally introduce or partially remove the solid acid catalyst to the reactor during the continuous reaction.

  The anhydrous (meth) acrylic acid is preferably charged so as to have a concentration of 0.05 to 50% by mass in the reaction solution.

  The molecular weight of the resulting polymer can be adjusted by adjusting the molar ratio of THF to anhydride (meth) acrylic acid.

  The reaction is usually carried out in the range of 0 to 100 ° C., preferably at 20 to 70 ° C. because the reaction rate is low at low temperatures and polymerization of the raw material anhydride or product may proceed at high temperatures. Ru.

  The reaction time is not particularly limited, but is usually selected in the range of 0.1 to 200 hours, preferably in the range of 0.5 to 100 hours, in consideration of the catalytic amount, the yield of the polymer, and the economy.

  The ring-opening polymerization reaction is usually carried out without addition of a solvent other than THF, but a solvent can also be used if necessary. As the solvent, an organic solvent used for ordinary organic chemical reactions can be used in consideration of the reaction substrate, the solubility of the product, and the stability under the reaction conditions. For example, hydrocarbons such as hexane, heptane and octane, ethers such as diethyl ether and dibutyl ether, aromatic hydrocarbons such as benzene, toluene and xylene can be mentioned, and even one or more kinds can be used in combination May be The reaction pressure may be any pressure that allows the reaction system to maintain the liquid phase, and is usually selected from the range of normal pressure to 10 MPa, preferably in the range of normal pressure to 5 MPa.

  The process of the invention is preferably carried out under an inert gas atmosphere, in which case any inert gas such as nitrogen or argon can be used.

  After completion of the ring-opening polymerization reaction of the present invention, polybutylene ether di (meth) acrylate can be obtained, for example, by the following operation. The solid acid catalyst contained in the reaction solution obtained by the ring-opening polymerization reaction is separated from the reaction product by filtration, decantation, centrifugation or the like and reused. When the catalyst is used in a continuous mode, the catalyst is simply left in the reactor while fresh reactant is supplied and the product is removed.

  In either of the batch system and the continuous system, after removal of the catalyst, the product is by-produced with the unreacted raw material (meth) acrylic acid is usually distilled off these unreacted raw materials under normal pressure or reduced pressure Or need to be separated by a washing operation. The recovered THF and anhydrous (meth) acrylic acid can be purified and recycled to the reaction, if necessary.

  The solid acid catalyst recovered by the above solid removal operation can be used again for the ring-opening polymerization reaction by removing the attached organic matter by a washing treatment with an organic solvent or a heating and baking treatment.

  EXAMPLES Hereinafter, the present invention will be more specifically described by way of examples, but the present invention is not limited to the examples unless it exceeds the gist.

(Preparation of raw materials)
THF used Wako Pure Chemical Industries super dehydrated grade. Methacrylic anhydride was purified by distillation and then dried with molecular sieves. The solid acid catalyst was dried by heating at 400 ° C. for 3 hours and then cooled in a desiccator.

(Polybutylene ether di (meth) acrylate analysis)
^It was determined by ¹ H-NMR measurement. In this measurement, about 5% by mass of a deuterated chloroform solution of the sample is put in a test tube of 5 mm in diameter, using a GSX-270 FT-NMR manufactured by JEOL Ltd., a measurement temperature of 25 ° C., an observation frequency of 270 MHz , In single pulse mode, with 16 integrations.

Example 1
Under a nitrogen atmosphere, 0.82 g of activated clay V2R (manufactured by Mizusawa Chemical Industries, Ltd.), 24.2 g (0.34 mol) of THF and 1.04 g (0.0067 mol) of methacrylic anhydride were charged. After heating and stirring at an internal temperature of 65 ° C. for 22 hours, NMR confirmed that the conversion of methacrylic anhydride was 100%. The catalyst was recovered by filtering the solution diluted with 100 mL of ethyl acetate through a membrane filter. After adding 10 ml each of saturated aqueous sodium hydrogen carbonate solution and saturated aqueous sodium hydrogen carbonate solution to the filtrate and washing three times, the solution was filtered through a membrane filter. Then, the solvent was concentrated by an evaporator followed by a vacuum pump to obtain polybutylene ether dimethacrylate (2.01 g). From NMR, the degree of polymerization of THF was 149, and the molecular weight was 10,700.

[Examples 2 to 10]
The results of the synthesis as in Example 1 are summarized in Table 1. However, as for Examples 4 to 10, post-treatment was not performed because the conversion rate of methacrylic anhydride was low.

Claims (4)

A method for producing polybutylene ether di (meth) acrylate by ring-opening polymerization of tetrahydrofuran in the presence of a solid acid catalyst and anhydrous (meth) acrylic acid ,
The manufacturing method of the polybutylene-ether di (meth) acrylate whose said solid acid catalyst is activated clay . The method for producing polybutylene ether di (meth) acrylate according to claim 1, wherein the solid acid catalyst is 0.001 to 100 times by mass with respect to the liquid phase . The method for producing polybutylene ether di (meth) acrylate according to claim 1 or 2, wherein the tetrahydrofuran is subjected to ring-opening polymerization under an inert gas atmosphere. The manufacturing method of the polybutylene-ether di (meth) acrylate of any one of Claims 1-3 which ring-opening-polymerizes the said tetrahydrofuran at 20-70 degreeC.