KR102480621B1 - Manufacturing method for low molecular weight acrylic resin - Google Patents

Abstract

The present invention relates to a method for preparing a low molecular weight acrylic resin, which reduces the internal pressure of the reaction vessel and maximizes the continuous operation time of a single screw extrusion reactor by controlling the temperature of the front and rear ends of the reaction vessel.

Description

Manufacturing method of low molecular weight acrylic resin {MANUFACTURING METHOD FOR LOW MOLECULAR WEIGHT ACRYLIC RESIN}

The present invention relates to a method for preparing a low molecular weight acrylic resin. Specifically, the present invention relates to a method for producing a low molecular weight acrylic resin capable of continuous polymerization without a pressure increase in a reaction vessel by gel.

Various optical members may be attached to the display device using an adhesive film. The adhesive film should maintain adhesiveness for a long time even when the display device is exposed to an external environment. Accordingly, studies are being actively conducted to improve the adhesive properties of the adhesive film, specifically, the adhesive durability. In particular, a method of securing adhesive physical properties of an adhesive film by including a low molecular weight acrylic resin when manufacturing the adhesive film is in the spotlight.

Conventionally, a low molecular weight acrylic resin has been prepared by reacting a solution containing an acrylic monomer, a reaction solvent, a chain extender, and the like using a batch reactor.

However, the acrylic resin prepared using the batch reactor has a problem of causing defects in the adhesive film due to the remaining reaction solvent and chain extender. Furthermore, the method of preparing a low molecular weight acrylic resin using a batch reactor has problems such as decomposition of reactants or explosion due to heat generated during polymerization.

Accordingly, a polymerization method using a continuous process that can solve the above problems by replacing the polymerization method using a batch reactor has been developed, but safety problems of the process due to pressure increase, decomposition problems due to exposure to high temperatures of raw materials, and polymerization process It was a situation in which it was practically impossible to effectively prepare a low molecular weight acrylic resin due to gelation problems in.

Therefore, research on improving the stability and efficiency of a method for producing a low molecular weight acrylic resin by appropriately adjusting the pressure generated in a continuous process while replacing the method using a batch reactor was required.

Japanese Patent Publication JP 2001-521948 A

The present invention is to provide a method for stably preparing a low molecular weight acrylic resin in a continuous process.

However, the problem to be solved by the present invention is not limited to the above-mentioned problem, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

An exemplary embodiment of the present invention is a method for continuously producing a low molecular weight acrylic resin by continuously polymerizing a non-solvent type acrylic composition containing at least one (meth)acrylate monomer and a thermal initiator in a single screw extrusion reactor, supplying a formulated acrylic composition to a reactor through an inlet; obtaining a low molecular weight acrylic resin by continuously polymerizing the supplied composition; and discharging the low molecular weight acrylic resin in the reaction tank through an outlet, maintaining the temperature of the front end of the reaction tank at 90° C. or more and 200° C. or less during the continuous polymerization, and keeping the temperature at the rear end of the reaction tank at 30° C. Provided is a method for continuously producing a low molecular weight acrylic resin maintained at a temperature below 70°C.

Since the method for producing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention does not use a separate molecular weight regulator, it is possible to prevent a problem of change of the acrylic resin over time due to the use of a molecular weight regulator.

Since the method for preparing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention is continuously polymerized using a single screw extrusion reactor, there is an advantage in that a low molecular weight acrylic resin can be stably prepared.

The method for producing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention has the advantage of maintaining the front end of the reaction vessel at a high temperature to soften the gel generated during continuous polymerization and maintaining the inside of the reaction vessel at a low pressure.

In the method for producing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention, the rear end of the reaction tank is maintained at a low temperature to prevent the polymerization reaction from proceeding additionally, thereby preventing gel formation.

The method for producing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention has the advantage of maximizing the continuous driving time of the single-screw extrusion reactor by lowering the rate of increase in internal pressure of the reactor by maintaining the front and rear ends of the reactor at a specific temperature. there is.

1 is a view showing a cross-section of a single screw extrusion reactor used in a method for producing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention.
2 is a cross-sectional view of a screw agitator of a single screw extrusion reactor used in a method for producing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention.

In the present specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

In this specification, the unit "parts by weight" means the ratio of the weight between each component.

In this specification, "A and/or B" means "A and B, or A or B".

In this specification, the term "monomer" may refer to a material capable of forming a covalent bond with an additional series of identical or different molecules under polymer formation reaction conditions.

In this specification, the term "(meth)acrylate" means "methacrylate or acrylate".

Throughout this specification, the "weight average molecular weight" of a compound may be calculated using the molecular weight and molecular weight distribution of the compound. Specifically, a sample sample having a concentration of 1 wt% of the compound was prepared by putting tetrahydrofuran (THF) and the compound in a 1 ml glass bottle, and the standard sample (polystyrene) and the sample sample were filtered (pore size). After filtering through 0.45 mm), it is injected into a GPC injector, and the molecular weight and molecular weight distribution of the compound can be obtained by comparing the elution time of the sample with the calibration curve of the standard sample. At this time, an Infinity II 1260 (Agilient Co.) can be used as a measuring device, and the flow rate can be set to 1.00 mL/min and the column temperature to 40.0 °C.

Throughout the present specification, the term "Poly Dispersion Index (PDI)" is the ratio of the weight average molecular weight and the number average molecular weight, which are converted values for polystyrene measured by GPC, by dividing the number average molecular weight from the weight average molecular weight can mean value.

Hereinafter, the present invention will be described in more detail.

A method for preparing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention is to continuously polymerize a non-solvent type acrylic composition including at least one type of (meth)acrylate monomer and a thermal initiator in a single screw extrusion reactor to obtain a low molecular weight acrylic resin. As a method for continuous production, supplying the non-solvent type acrylic composition to a reaction tank through an inlet; obtaining a low molecular weight acrylic resin by continuously polymerizing the supplied composition; and discharging the low molecular weight acrylic resin in the reaction tank through an outlet, maintaining the temperature of the front end of the reaction tank at 90° C. or more and 200° C. or less during the continuous polymerization, and keeping the temperature at the rear end of the reaction tank at 30° C. Keep below 70 ℃.

Hereinafter, the manufacturing method will be described in more detail with reference to the drawings.

In one embodiment of the present invention, a low molecular weight acrylic resin is prepared using a non-solvent type acrylic composition including at least one type of (meth)acrylate-based monomer and a thermal initiator.

According to an exemplary embodiment of the present invention, the (meth)acrylate-based monomer is an alkyl group-containing (meth)acrylate-based monomer, a cycloalkyl group-containing (meth)acrylate-based monomer, and a polar functional group-containing (meth)acrylate-based monomer. It may include one or more selected species. That is, the low molecular weight acrylic resin may be prepared by polymerizing at least one of the acrylic monomers.

According to an exemplary embodiment of the present invention, the alkyl group-containing (meth)acrylate-based monomer may be one in which an alkyl group is bonded to a (meth)acrylate-based monomer. In addition, the cycloalkyl group-containing (meth)acrylate-based monomer may be a cycloalkyl group bonded to a (meth)acrylate-based monomer. Furthermore, the polar functional group-containing (meth)acrylate-based monomer may be a polar functional group bonded.

In the present specification, the term "alkyl group" may refer to a functional group including chain-like and/or branched hydrocarbons, and specifically, chain-like and/or branched hydrocarbons having 1 to 20 carbon atoms. It may mean a functional group containing.

In the present specification, the term "cycloalkyl group" may refer to a functional group including a hydrocarbon bonded in a cyclic form, and specifically may mean a functional group including a hydrocarbon bonded in a cyclic form having 3 to 20 carbon atoms, More specifically, it may mean a functional group including a carbon ring structure in which unsaturated bonds do not exist in the functional group and including a monocyclic ring or polycyclic ring having 3 to 20 carbon atoms.

According to an exemplary embodiment of the present invention, the alkyl group-containing (meth)acrylate-based monomer is methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate , n-butyl (meth) acrylate, t-butyl (meth) acrylate, sec-butyl (meth) acrylate, pentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethylbutyl ( It may include at least one of meth)acrylate, n-octyl(meth)acrylate, and isooctyl(meth)acrylate.

According to an exemplary embodiment of the present invention, the cycloalkyl group-containing (meth)acrylate-based monomer is cyclohexyl acrylate (CHA), cyclohexyl methacrylate (CHMA), isobornyl acrylate (IBOA), isobornyl methacryl It may include at least one of late (IBOMA), isobornylmethyl (meth)acrylate, and 3,3,5-trimethylcyclohexylacrylate (TMCHA, 3,3,5-trimethylcyclohexylacrylate).

According to an exemplary embodiment of the present invention, the polar functional group-containing (meth)acrylate-based monomer is a hydroxy group-containing (meth)acrylate-based monomer, a carboxyl group-containing (meth)acrylate-based monomer and a nitrogen-containing (meth)acrylate-based monomer may include at least one of them.

Specifically, the hydroxy group-containing (meth)acrylate-based monomer is 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxy It may include at least one of hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 2-hydroxyethylene glycol (meth) acrylate, and 2-hydroxypropylene glycol (meth) acrylate. .

In addition, the carboxyl group-containing (meth)acrylate-based monomers are acrylic acid, methacrylic acid, 2-carboxyethyl acrylic acid, 3-carboxypropyl acrylic acid, 2-(meth)acryloyloxy acetic acid, 3-(meth)acryloyloxy cypropyl acid, 4-(meth)acryloyloxy butyric acid, and at least one of acrylic acid duplexes.

According to an exemplary embodiment of the present invention, the nitrogen-containing (meth)acrylate-based monomer is 2-isocyanatoethyl (meth)acrylate, 3-isocyanatopropyl (meth)acrylate, 4-isocyanatoethyl at least one of anetobutyl (meth)acrylate and (meth)acrylamide.

According to an exemplary embodiment of the present invention, the solvent-free acrylic composition includes a thermal initiator. When the non-solvent type acrylic composition includes a thermal initiator, polymerization of at least one type of (meth)acrylate monomer included in the non-solvent type acrylic composition to a low molecular weight acrylic resin may be initiated. If the thermal initiator is an initiator that triggers crosslinking by heating, the type is not particularly limited, but may include, for example, at least one selected from the group consisting of azo-based thermal initiators and peroxy-based thermal initiators.

According to an exemplary embodiment of the present invention, the azo-based thermal initiator is 2,2'-azobis (2-methylbutyronitrile) [V-59, Wako Co.], 2,2'-azobis (isobutyro nitrile) [V-60, Wako], 2,2'-azobis (2,4-dimethylvaleronitrile) [V-65, Wako], 4,4-azobis (4-cyanovaleric acid ), 1,1'-azobis (cyclohexanecarbonitrile) and 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) [V-70, Wako]. Not limited.

According to an exemplary embodiment of the present invention, the peroxy-based thermal initiator is tetramethylbutylperoxy neodecanoate (ex. Perocta ND, NOF), bis (4-butylcyclohexyl) peroxydicarbonate (ex. Peroyl TCP, NOF Co. (product), di(2-ethylhexyl) peroxy carbonate, butyl peroxy neodecanoate (ex. Perbutyl ND, NOF Co. (product)), dipropyl peroxy dicarbonate (ex. Peroyl NPP, NOF Co. (product)), Diisopropyl Peroxy Dicarbonate (ex. Peroyl IPP, NOF Co. (product)), Diethoxyethyl Peroxy Dicarbonate (ex. Peroyl EEP, NOF Co. (product)) , Diethoxyhexyl Peroxy Dicarbonate (ex. Peroyl OEP, NOF Co. (product)), Hexyl Peroxy Dicarbonate (ex. Perhexyl ND, NOF Co. (product)), Dimethoxybutyl Peroxy Dicarbonate (ex. Peroyl MBP, NOF Co. (manufactured), bis(3-methoxy-3-methoxybutyl) peroxy dicarbonate (ex. Peroyl SOP, NOF Co. (manufactured)), dibutyl peroxy dicarbonate, dicetyl ) Peroxy dicarbonate, dimyristyl peroxy dicarbonate, 1,1,3,3-tetramethylbutyl peroxypivalate, hexyl peroxypivalate (ex. Perhexyl PV, NOF Corporation ( )), butyl peroxy pivalate (ex. Perbutyl, NOF Co. (product)), trimethyl hexanoyl peroxide (ex. Peroyl 355, NOF Co. (product)), dimethyl hydroxybutyl peroxyneodecanoate ( ex. Luperox 610M75, Atofina (product)), amyl peroxyneodecanoate (ex. Luperox 546M75, Atofina (product)), butyl peroxyneodecanoate (ex. Luperox 10M75, Atofina (product)), t -Butylperoxyneoheptanoate, amylperoxypivalate (ex. Luperox 546M75, Alofina (manufactured by)), t-butylperoxypivalate, t-amylperoxy-2-ethylhexanoate, lauryl perox Seed, dilauroyl peroxide, didecanoyl peroxide, benzoyl peroxide, dibenzoyl peroxide, 2,2-bis(tert-butylperoxy)butane, 1,1-bis(tert-butyl Peroxy)cyclohexane, 2,5-bis(butylperoxy)-2,5-dimethylhexane, 2,5-bis(tert-butylperoxy)-1-methylethyl)benzene, 1,1-bis( tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butyl hydroperoxide, tert-butyl peroxide, tert-butyl peroxybenzoate, tert-butylperoxy isopropyl carbonate, cumene hydroxy cyperoxide, dicumyl peroxide, lauroyl peroxide, and 2,4-pentanedione peroxide; and the like, but are not limited thereto.

According to an exemplary embodiment of the present invention, the content of the thermal initiator is 0.01 parts by weight or more and 1 part by weight or less, specifically 0.05 parts by weight or more and 0.7 parts by weight or less, 0.1 parts by weight based on 100 parts by weight of the (meth)acrylate-based monomer. part or more and less than or equal to 0.5 parts by weight. Within the content range of the thermal initiator, polymerization of the (meth)acrylate-based monomer may be initiated, and over-polymerization may be prevented to secure a weight average molecular weight range of the acrylic resin.

According to one embodiment of the present invention, the acrylic composition is a solvent-free type. That is, the solvent-free acrylic composition does not include a separate solvent (solvent) required for the polymerization reaction. That is, the low molecular weight acrylic resin is prepared by bulk polymerization, not solution polymerization, of the solvent-free acrylic composition. The solvent is a solvent required for the polymerization reaction, and may mean a solvent known in the art as a solvent that can be used to prepare an acrylic resin.

According to one embodiment of the present invention, the non-solvent type acrylic composition may not contain a molecular weight modifier.

In the present specification, the molecular weight modifier may refer to a material that increases or decreases the molecular weight of the polymerization product without affecting the polymerization rate by being added in the polymerization reaction.

1 is a schematic diagram of a single screw extrusion reactor used in a method for producing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention.

According to an exemplary embodiment of the present invention, the single screw extrusion reactor 10 includes a reaction tank 100, an inlet 200 and an outlet 300.

The inlet 200 may be connected to one end of the reaction tank 100, and the outlet 300 may be connected to the other end of the reaction tank 100. That is, in the single screw extrusion reactor 10, the reaction tank 100, the inlet 200, and the outlet 300 may be sequentially connected.

In addition, the reaction tank 100 may be divided into a front end 110 and a rear end 120.

Also, according to an exemplary embodiment of the present invention, the inlet 200, the reaction tank 100, and the outlet 300 may have the same or different diameters and/or the same or different lengths.

In the method for producing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention, first, the solvent-free acrylic composition is supplied to the reaction tank 100 through the inlet 200 of the single screw extrusion reactor.

According to one embodiment of the present invention, the front end of the reaction tank may be located at one side of the reaction tank and connected to the inlet. In addition, the front end of the reactor is connected to the inlet to maintain the solvent-free acrylic composition supplied from the inlet at a high temperature. Accordingly, an activation reaction of the initiator included in the non-solvent type acrylic composition is rapidly induced at the front end of the reaction vessel. In addition, as the front end of the reaction vessel is maintained at a high temperature, the gel generated in the continuous polymerization is softened, thereby preventing the pressure inside the reaction vessel from rising.

According to one embodiment of the present invention, the rear end of the reaction tank may be located on the other side of the reaction tank and connected to the outlet. In addition, the rear end of the reactor is connected to the outlet to discharge the low molecular weight acrylic resin prepared from the non-solvent type acrylic composition. In addition, the rear end of the reaction tank may cool the low molecular weight acrylic resin prepared by polymerization with a small amount of the non-solvent type acrylic composition remaining unpolymerized at the front end of the reaction tank. In addition, the rear end of the reactor cools the residual non-solvent acrylic composition or the low molecular weight acrylic resin to prevent further polymerization, thereby preventing the residual solvent free acrylic composition or the low molecular weight acrylic resin from forming a gel by polymerization. there is. Specifically, the rear end of the reaction tank cools the residual solvent-free acrylic composition and the low molecular weight acrylic resin to suppress the radical side reaction of the remaining thermal initiator so that a gel is formed by polymerization from the residual solventless acrylic composition and the low molecular weight acrylic resin. formation can be prevented.

According to an exemplary embodiment of the present invention, the reaction vessel included in the single screw extrusion reactor may include a screw stirrer. In addition, the screw stirrer includes an agitation shaft connected from one end to the other end of the reaction vessel; and a plurality of stirring blades provided around the stirring shaft. In addition, the plurality of stirring blades may be provided spaced apart from each other, and the stirring blades may be provided in a wound form around the stirring shaft.

According to an exemplary embodiment of the present invention, the screw stirrer may stir the non-solvent type acrylic composition supplied to the reaction tank. Specifically, a plurality of agitation blades included in the screw agitator may be rotated according to the direction of rotation of the agitation shaft, and accordingly, the non-solvent type acrylic composition supplied to the reactor is stirred and then continuously polymerized into a low molecular weight acrylic resin. this could be possible

According to one embodiment of the present invention, the ends of the stirring blades may be spaced apart from the inner wall of the reaction vessel, and specifically, the ends of the stirring blades may not come into contact with the inner wall of the reaction vessel. Accordingly, it is possible to prevent the inner wall of the reaction vessel from being damaged by the agitation blades during agitation of the screw agitator.

According to one embodiment of the present invention, the separation distance between adjacent stirring blades of the screw stirrer may be 10 mm or more and 20 mm or less. In addition, according to one embodiment of the present invention, the shortest distance from the outer end of the agitation blades of the screw agitator to the agitation shaft may be 5 mm or more and 50 mm or less.

A continuous polymerization reaction of the solvent-free acrylic composition into the low molecular weight acrylic resin may be smoothly performed within the range of the distance between the adjacent stirring blades and the shortest distance from the outer end of the stirring blade to the stirring shaft. there is. Specifically, within the above range, exothermic control of the continuous polymerization reaction of the solvent-free acrylic composition to the low molecular weight acrylic resin can be easily controlled, and the low molecular weight acrylic resin produced is the weight average according to one embodiment of the present invention. It can be made to have a range of molecular weight, conversion rate, and polydispersity index.

In this specification, the term “separation distance between adjacent stirring blades” may mean the pitch of the stirring blades, and specifically, at one end of one stirring blade, the other stirring blade provided adjacent thereto. It may mean the shortest distance to one end.

In this specification, the term "shortest distance from the outer end of the stirring blade to the stirring shaft" may mean the length of a vertical line from an imaginary line parallel to the stirring shaft at the outer end of the stirring blade to the surface of the stirring shaft. there is.

According to one embodiment of the present invention, in the step of supplying the solvent-free acrylic composition to the reaction tank, the solvent-free acrylic composition is supplied to the reaction tank at a feed flow rate of 30 mL/min or more and 400 mL/min or less. may be supplied to Specifically, the supply flow rate of the solvent-free acrylic composition is 30 mL/min or more and 400 mL/min or less, 50 mL/min or more and 350 mL/min or less, 80 mL/min or more and 300 mL/min or less, 100 mL/min or more. It may be 250 mL/min or less, 150 mL/min or more and 200 mL/min or less. Within the supply flow rate range of the non-solvent type acrylic composition, a continuous polymerization reaction from the non-solvent type acrylic composition to the low molecular weight acrylic resin can occur smoothly. Meanwhile, the supply flow rate of the solvent-free acrylic composition may be appropriately adjusted according to the size of the single screw extrusion reactor. Specifically, the supply flow rate of the solvent-free acrylic composition may be appropriately adjusted according to the size of the single-screw extrusion reactor so as to realize a reaction time in the range described below.

In the method for producing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention, the supplied composition is continuously polymerized to obtain a low molecular weight acrylic resin.

According to an exemplary embodiment of the present invention, the temperature of the front end of the reactor is maintained at 90 °C or more and 200 °C or less during the continuous polymerization. Specifically, it can be maintained at 92.5 ° C or more and 190 ° C or less, 95 ° C or more and 180 ° C or less, 97.5 ° C or more and 170 ° C or less, 100 ° C or more and 160 ° C or less, 102.5 ° C or more and 150 ° C or less, or 105 ° C or more and 150 ° C or less. Within the temperature range of the front end of the reactor, continuous polymerization of the solvent-free acrylic composition into a low molecular weight acrylic resin can be smoothly performed. Specifically, when the temperature of the front end of the reaction tank is less than the above range, polymerization in the reaction tank is not smoothly performed, so that the solvent-free acrylic composition does not polymerize and the remaining solvent-free acrylic composition increases. In addition, when the temperature of the front end of the reaction tank exceeds the above range, the non-solvent type acrylic composition is over-polymerized and the acrylic resin remains in the reaction tank in a gelled state. Furthermore, when the temperature of the front end of the reaction vessel exceeds the above range, overpolymerization may occur in the reaction vessel, causing the reaction vessel to explode due to an increase in temperature and pressure. In addition, when the temperature of the front end of the reaction tank exceeds the above range, a problem in that the produced low molecular weight acrylic resin is decomposed may occur.

According to an exemplary embodiment of the present invention, during the continuous polymerization, the temperature of the rear end of the reactor is maintained at 30 °C or more and less than 70 °C. Specifically, it may be carried out while maintaining the temperature of the rear end of the reactor at 35 ° C or more and 67.5 ° C or less, 40 ° C or more and 65 ° C or less, 45 ° C or more and 62.5 ° C or less, 50 ° C or more and 60 ° C or less. Within the temperature range of the rear end of the reaction tank, the solvent-free acrylic composition controls continuous polymerization into a low molecular weight acrylic resin and at the same time prevents the residual solvent-free acrylic composition remaining after polymerization at the front end from further polymerization. . Specifically, by controlling the temperature at the rear end of the reaction tank within the above-described range, the problem of increasing the residual amount of the non-solvent type acrylic composition in the reaction tank is prevented, and the polymerization of the non-solvent type acrylic composition proceeds excessively, resulting in additional gel formation. problems can be prevented.

According to an exemplary embodiment of the present invention, during the continuous polymerization, the temperature difference between the front end and the rear end of the reactor may be 50 °C or more and 150 °C or less. Specifically, the temperature difference between the front end and the rear end of the reactor is 55 ° C or more and 140 ° C or less, 60 ° C or more and 130 ° C or less, 65 ° C or more and 120 ° C or less, 70 ° C or more and 110 ° C or less, 75 ° C or more and 100 ° C or less, 75 ° C Continuous polymerization may be performed by maintaining the temperature above 90° C. or less. By adjusting the temperature difference between the front end and the rear end of the reaction tank within the above-described range, the residual amount of the solvent-free acrylic composition in the reaction tank is reduced in the process of continuous polymerization of the solvent-free acrylic composition at the front end of the reaction tank, Curing of the acrylic resin can be prevented. In addition, gelation caused by overpolymerization may be prevented by preventing overpolymerization of the acrylic resin at the rear end of the reaction vessel, and as a result, the pressure inside the reaction vessel may be maintained at a low level. Furthermore, by controlling the temperature difference between the front end and the rear end of the reaction vessel within the above-described range, the time to reach the standard pressure that the single screw extrusion reactor can withstand is increased by reducing the rate of increase of the internal pressure of the reaction vessel, , This has the effect of maximizing the time available for continuous operation of the single screw extrusion reactor.

According to an exemplary embodiment of the present invention, the reaction tank 100 may include a screw stirrer 101, and the screw stirrer 101 includes an agitation shaft 102 connected from one end to the other end of the reaction tank, and A plurality of stirring blades 103 provided along the circumference of the stirring shaft may be included. As the stirring shaft rotates, the non-solvent type acrylic composition supplied to the reaction tank may be mixed, and accordingly, continuous polymerization of the low molecular weight acrylic resin may be possible.

The ratio of the lengths of the front end and the rear end may be 1:0.1 or more and 1:2 or less. Specifically, the ratio of the lengths of the front end and the rear end may be 1:0.3 or more and 1:1.7 or less, 1:0.5 or more and 1:1.5 or less, 1:0.7 or more and 1:1.3 or less. By adjusting the ratio of the lengths of the front end and the rear end of the reaction vessel within the above-mentioned range, the amount of gel cured and produced in the polymerization reaction can be reduced, and the pressure in the reaction vessel can be reduced.

According to an exemplary embodiment of the present invention, the reaction bath 100 may be provided in the first thermostatic bath 400 and the second thermostatic bath 500 . In addition, the temperature of the front end 110 of the reaction tank may be adjusted according to the temperature of the fruit supplied through the fruit supply part 401 of the first constant temperature bath 400 and discharged along the fruit discharge part 402. . In addition, the temperature of the rear end 120 of the reaction tank may be adjusted according to the temperature of the fruit supplied through the fruit supply part 501 of the second constant temperature bath 500 and discharged along the fruit discharge part 502. . In addition, the fruit may refer to a fluid used as a heat transfer medium in the art, and may be freely selected from known materials as long as it can be used to maintain the temperature range. Specifically, the fruit may use silicone oil.

Furthermore, the first thermostat and the second thermostat may be continuously or discontinuously connected. Specifically, when the first constant temperature bath and the second constant temperature bath are continuously connected, the temperature at the boundary between the front end and the rear end of the reaction bath may be gently decreased along the longitudinal direction of the single screw extrusion reactor. Also, when the first thermostat and the second thermostat are discontinuously connected, the temperature at the boundary between the front end and the rear end of the reaction tank may rapidly decrease along the longitudinal direction of the single screw extrusion reactor.

2 is a cross-sectional side view of a screw stirrer of a single screw extrusion reactor used in a method for producing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention. Referring to FIG. 2, the "separation distance between adjacent stirring blades" in the present specification may be indicated by X in FIG. 2, and the "shortest distance from the outer end of the stirring blades to the stirring shaft" in the present specification is 2 to Y.

In addition, the method for producing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention further includes a screw stirrer, so that the produced low molecular weight acrylic resin is cured naturally or adhered to the inner wall of the reaction vessel. In addition, in the method for producing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention, the low molecular weight acrylic resin can be sufficiently formed in a constant form even if the process time continues, and the stability of the polymerization reaction to the low molecular weight acrylic resin is secured. There are advantages.

Further, according to an exemplary embodiment of the present invention, the fluid behavior of the solvent-free acrylic composition supplied to the reactor may be a turbulent flow. That is, the composition of the components included in the solvent-free acrylic composition may not change depending on the radial direction of the reaction vessel and may change depending on the axial direction of the reaction vessel.

According to one embodiment of the present invention, the single-screw extrusion reactor, specifically, the diameter of the reactor of the single-screw extrusion reactor may not change along the longitudinal direction of the single-screw extrusion reactor.

Further, according to an exemplary embodiment of the present invention, the single screw extrusion reactor, specifically, the diameter of the reactor of the single screw extrusion reactor may vary along the longitudinal direction of the single screw extrusion reactor. That is, the diameter of the reactor may increase or decrease along the longitudinal direction of the single screw extrusion reactor. Accordingly, the reaction rate of the polymerization reaction of the acrylic monomer included in the solvent-free acrylic composition supplied to the single screw extrusion reactor may vary depending on the volume of the single screw extrusion reactor and the supply amount of the acrylic monomer supplied.

According to an exemplary embodiment of the present invention, the single screw extrusion reactor may be formed of stainless steel (steel use stainless, SUS). Accordingly, heat energy supplied through an external heat medium can be transferred to the single screw extrusion reactor with high efficiency.

In the present specification, the length of the reaction vessel may mean a maximum distance from one end of the reaction vessel to the other end in an axial direction. Also, the diameter of the reaction vessel may mean a maximum distance from one end of the reaction vessel to the other end in a radial direction.

According to an exemplary embodiment of the present invention, the ratio of the length to the diameter of the reaction vessel may be 10:1 or more and 1,000:1 or less. Specifically, the ratio of the length and diameter of the reactor may be 50:1 or more and 900:1 or less, 100:1 or more and 700:1 or less, 150:1 or more and 500:1 or less, or 200:1 or more and 400:1 or less. Within the ratio range of the length and diameter of the reaction vessel, temperature control within the reaction vessel may be facilitated, and the supplied solvent-free acrylic composition may not remain in the reaction vessel, and thus the solvent-free acrylic composition may be low molecular weight acrylic composition. It can be sufficiently polymerized into a resin.

According to an exemplary embodiment of the present invention, the length of the reaction tank may be 0.1 m or more and 100 m or less. Specifically, the length of the reactor may be 0.2 m or more and 75 m or less, 0.3 m or more and 50 m or less, 0.4 m or more and 25 m or less, 0.5 m or more and 20 m or less, 0.7 m or more and 15 m or less, 0.9 m or more and 10 m or less, and 1 m or more and 5 m or less. By adjusting the length of the reaction vessel within the above-described range, the time during which the supplied non-solvent type acrylic composition is polymerized can be controlled, and accordingly, an increase in pressure in the reaction vessel can be prevented.

According to one embodiment of the present invention, the diameter of the reaction vessel may be greater than or equal to 1 mm and less than or equal to 100 mm. Specifically, the diameter of the reaction vessel may be 3 mm or more and 80 mm or less, 5 mm or more and 60 mm or less, 7 mm or more and 50 mm or less, and 10 mm or more and 40 mm or less. By adjusting the diameter of the reaction vessel within the above range, it is possible to easily control the temperature of the reaction vessel.

In this specification, the term "continuous polymerization" may mean polymerization of a monomer according to a continuous flow of fluid.

According to one embodiment of the present invention, the continuous polymerization may be carried out while maintaining the agitation speed of the screw stirrer in the reaction vessel at 150 rpm or less, and specifically, maintained at 50 rpm or more and 150 rpm or less. In addition, the stirring speed may mean the number of rotations per time (unit: minute) of the stirring blades included in the screw stirrer. Within the stirring speed range, continuous polymerization into the low molecular weight acrylic resin can be smoothly performed, and the prepared low molecular weight acrylic resin can be sufficiently discharged without accumulation in the reaction tank.

According to an exemplary embodiment of the present invention, the continuous polymerization is 1 minute or more and 120 minutes or less, specifically, in the step of obtaining the low molecular weight acrylic resin, the continuous polymerization is 1 minute or more and 100 minutes or less, 2 minutes or more and 80 minutes or less, 3 minutes or more and 60 minutes or less, 5 minutes or more and 40 minutes or less, 6 minutes or more and 30 minutes or less, and 7 minutes or more and 15 minutes or less. That is, the continuous polymerization reaction time from the non-solvent type acrylic composition to the low molecular weight acrylic resin may be 1 minute or more and 120 minutes or less. Within the range of the continuous polymerization reaction time, the low molecular weight acrylic resin can be smoothly formed, and the phenomenon of curing (gelation) due to heat generation of the low molecular weight acrylic resin not being controlled can be prevented, and the continuous polymerization reaction accordingly stability can be ensured.

According to an exemplary embodiment of the present invention, the continuous polymerization may be performed while maintaining the pressure of the reactor at 5 bar or less. Specifically, more than 0 bar and less than 4.5 bar, more than 0.2 bar and less than 4.0 bar, more than 0.4 bar and less than 3.5 bar, more than 0.6 bar and less than 3.0 bar, more than 1.0 bar and less than 2.5 bar, more than 1.5 bar and less than 2.0 bar. there is. Within the pressure range of the reactor, a continuous polymerization reaction of the low molecular weight acrylic composition to the low molecular weight acrylic resin may be stably performed.

According to one embodiment of the present invention, the low molecular weight acrylic resin in the reaction tank is discharged through the outlet.

According to an exemplary embodiment of the present invention, the flow rate at which the solvent-free acrylic composition is supplied to the supply port of the single screw extrusion reactor and the flow rate at which the low molecular weight acrylic resin is discharged from the outlet port of the single screw extrusion reactor may be the same. That is, according to one embodiment of the present invention, the step of discharging the low molecular weight acrylic resin may be discharging the formed acrylic resin through the outlet at a discharge rate of 30 mL/min or more and 400 mL/min or less.

Also in this case, the single screw extrusion reactor can maintain a steady-state. That is, in the method for producing a low molecular weight acrylic resin according to an exemplary embodiment of the present invention, the production rate of the low molecular weight acrylic resin may not change with time.

Hereinafter, the low molecular weight acrylic resin prepared according to the above production method will be described in more detail.

According to an exemplary embodiment of the present invention, the weight average molecular weight of the low molecular weight acrylic resin is 1,000 g/mol or more and 150,000 g/mol or less, 2,000 g/mol or more and 140,000 g/mol or less, 3,000 g/mol or more and 130,000 g/mol or less, 4,000 g/mol or more and 120,000 g/mol or less, or 5,000 g/mol or more and 100,000 g/mol or less. When the low molecular weight acrylic resin has a weight average molecular weight within the above range, when the low molecular weight acrylic resin is included in the pressure-sensitive adhesive composition, it can exhibit excellent adhesive strength and can be applied to various optical materials.

According to one embodiment of the present invention, the glass transition temperature of the low molecular weight acrylic resin may be -50 ℃ or more and 100 ℃ or less. Specifically, the glass transition temperature may be -40 ℃ or more and 90 ℃ or less, -30 ℃ or more and 80 ℃ or less, -20 ℃ or more and 70 ℃ or less. The low molecular weight acrylic resin was measured using differential scanning calorimetry (DSC). When the low molecular weight acrylic resin has a glass transition temperature within the above range, the holding power of the low molecular weight acrylic resin at a high temperature may be effectively improved.

According to an exemplary embodiment of the present invention, the polydispersity index of the low molecular weight acrylic resin may be 5 or less, specifically 2 or more and 5 or less, 2 or more and 3.5 or less, 2.5 or more and 5 or less, or 2.5 or more and 3.5 or less. The fact that the low molecular weight acrylic resin has a polydispersity index within the aforementioned range may mean that heat transfer is uniform during the continuous polymerization of the low molecular weight acrylic resin.

According to an exemplary embodiment of the present invention, the low molecular weight acrylic resin has a conversion rate defined by Formula 1 below of 20% or more and 100% or less, specifically, the conversion rate of the low molecular weight acrylic resin is 30% or more and 97.5% or less, 40% or more 95% or less, 50% or more and 92.5% or less, 60% or more and 90% or less, 70% or more and 87.5% or less, more specifically 75% or more and 85% or less:

[Formula 1]

C = B/A × 100

In Formula 1, A means the weight (g) of the low molecular weight acrylic resin, B means the weight (g) of the dry matter of the low molecular weight acrylic resin, and C means the conversion rate (%).

According to an exemplary embodiment of the present invention, the dried product of the low molecular weight acrylic resin may be obtained by drying the low molecular weight acrylic resin at a temperature of about 150 °C for about 50 minutes.

The fact that the low molecular weight acrylic resin has a conversion rate within the aforementioned range may mean that the supplied non-solvent type acrylic composition hardly remains in the reaction tank, and most of the low molecular weight acrylic resin is continuously polymerized.

Hereinafter, examples will be described in detail to explain the present invention in detail. However, embodiments according to the present invention can be modified in many different forms, and the scope of the present invention is not construed as being limited to the embodiments described below. The embodiments herein are provided to more completely explain the present invention to those skilled in the art.

[ Example One]

A first thermostat including a first heat supply unit and a first heat discharge unit, a second thermostat including a second heat supply unit and a second heat discharge unit, and a single screw extrusion reactor provided in the first thermostat and the second thermostat were prepared. Specifically, the single screw extrusion reactor includes a screw stirrer, a reaction tank, an inlet provided at one end of the reaction tank, and an outlet provided at the other end of the reaction tank. More specifically, the screw stirrer includes a stirring shaft connected from one end of the reaction tank to the other end, and a plurality of stirring blades provided around the stirring shaft. In addition, the single-screw extrusion reactor was used to include two cylindrical reactors, and the length of the cylindrical reactor was 500 mm. In addition, the separation distance between the adjacent stirring blades was about 20 mm, and the shortest distance from the outer end of the stirring blades to the stirring shaft was about 10 mm.

52 parts by weight of 2-ethylhexyl acrylate (2-EHA), 38 parts by weight of isobornyl acrylate (IBOA), and 10 parts by weight of hydroxyethyl acrylate (HEA), based on 100 parts by weight of the total, 0.5 parts by weight of azo thermal initiators [2,2'-azobis(2,4-dimethylvaleronitrile); V-65, Wako] to prepare a solvent-free acrylic composition.

The temperature of the front end of the reactor was maintained at about 150 °C by circulating silicon oil, which is a heat medium of about 150 °C, through the first heat medium supply part and the first heat medium discharge part of the first constant temperature tank. In addition, silicone oil, which is a heat medium of about 65 ° C., was circulated through the second heat medium supply part and the second heat medium discharge part of the second thermostat to maintain the temperature of the rear end of the reaction tank at about 65 ° C.

Then, the non-solvent type acrylic composition was supplied to the reactor at a flow rate of 200 mL/min through the inlet of the single screw extrusion reactor.

The stirring speed of the screw stirrer in the reaction vessel was adjusted to 120 rpm, and continuous polymerization was performed in bulk for 2 hours to form a low molecular weight acrylic resin. Then, the formed low molecular weight acrylic resin was discharged at the same flow rate as the supply flow rate through the outlet of the single screw extrusion reactor to prepare a low molecular weight acrylic resin.

[ Example 2]

A low molecular weight acrylic resin was prepared in the same manner as in Example 1, except that the content of the thermal initiator was adjusted to 0.7 parts by weight.

[ Example 3]

A low molecular weight acrylic resin was prepared in the same manner as in Example 1, except that the content of the thermal initiator was adjusted to 0.7 parts by weight and the temperature of the front end of the reactor was maintained at about 130 °C.

[ Example 4]

A low molecular weight acrylic resin was prepared in the same manner as in Example 1, except that the temperature of the rear end was maintained at about 40 °C.

[ comparative example One]

A low molecular weight acrylic resin was prepared in the same manner as in Example 1, except that the temperature at the front end of the reaction tank was maintained at about 105 ° C and the temperature at the rear end of the reaction tank was maintained at about 105 ° C, and polymerization was continuously performed for 1 hour and 20 minutes. manufactured.

[ Experimental Example 1] - weight average molecular weight and polydispersity index measurement

After collecting 0.04 g of the low molecular weight acrylic resin according to Examples 1 to 4 and Comparative Example 1, a sample was prepared by adding 10 g of the low molecular weight acrylic resin tetrahydrofuran solvent.

The weight average molecular weight and polydispersity index of the sample were measured using GPC (Agilnet 1260), and are shown in Table 1 below.

[ Experimental example 2] - Measurement of conversion rate

Samples were prepared by collecting 0.1 g (A) of the low molecular weight acrylic resin according to Examples 1 to 4 and Comparative Example 1.

The weight (B) after drying the sample in an oven at 150 ° C. for about 50 minutes was measured, and the conversion rate was measured after substituting this into the general formula 1, and it is shown in Table 1 below.

[ Experimental example 3] - 1 hour after the start of continuous polymerization reaction tank internal pressure measurement

A Bourdon tube pressure gauge (manufacturer: Samsung, model name) measuring the internal pressure of the reaction tank 1 hour after the continuous polymerization started when the solvent-free acrylic composition according to Examples 1 to 4 and Comparative Example 1 was supplied to the reaction tank and installed at the inlet. : 100 pie pressure gauge) was measured using, which is shown in Table 1 below.

[ Experimental example 4] - Measurement of continuous operation time of single screw extrusion reactor

By continuously driving the single-screw extrusion reactor, the solvent-free acrylic composition according to Examples 1 to 4 and Comparative Example 1 is supplied to the reaction tank and the internal pressure of the reaction tank is 5 bar, which is the standard for maintaining the stability of the reaction tank, from the time polymerization starts. The time to reach was measured. The internal pressure of the reactor was measured using a Bourdon tube pressure gauge (manufacturer: Samsung, model name: pressure gauge 100 Pi) installed at the inlet, and is shown in Table 1 below.

division weight average molecular weight
(×10,000g/mol) polydispersity index
(-) conversion rate
(%) Internal pressure of the reactor 1 hour after the start of continuous polymerization
(bar) Continuous operation time of single screw extrusion reactor Example 1 3.4 3.1 85.0 2.0 2 hours Example 2 2.5 2.9 84.0 1.5 2 hours Example 3 2.5 3.1 83.0 1.7 2 hours Example 4 3.3 3.0 83.4 1.9 2 hours Comparative Example 1 3.5 3.3 83.5 3.0 1 hour 20 minutes

According to Table 1, it can be confirmed that the method for preparing the low molecular weight resin according to Examples 1 to 4 can produce a low molecular weight acrylic resin having a weight average molecular weight of about 25,000 g/mol to 34,000 g/mol at a high conversion rate. The internal pressure of the reactor 1 hour after the start of the continuous polymerization corresponds to a pressure of 1.5 bar to 2.0 bar, so even after the continuous polymerization progress time, the pressure inside the single screw extrusion reactor is maintained at a low level to maintain process stability. was able to confirm that In addition, even if the continuous polymerization proceeded, the polymerization reaction could be continuously carried out for 2 hours due to the low rate of increase of the internal pressure of the reactor. That is, it was confirmed that the single screw extrusion reactor could be operated continuously for 2 hours.

On the other hand, in the method according to Comparative Example 1 in which the front and rear ends of the reactor are maintained at the same temperature, 105° C., the internal pressure of the reactor 1 hour after the start of the continuous polymerization corresponds to 3.0 bar, and the high pressure causes the It was confirmed that the physical properties of the low molecular weight acrylic resin were changed and the low molecular weight acrylic resin generated inside the reactor was leaked to the outside due to the pressure. Furthermore, it was confirmed that the process stability deteriorated due to the high pressure inside the reaction tank, and when the polymerization reaction proceeded continuously due to the high rate of increase in the pressure inside the reaction tank, the pressure inside the reaction tank increased for safety reasons. The single screw extrusion reactor run was stopped after 20 minutes.

In summary, in the case of using a single-screw extrusion reactor equipped with a reaction tank in which a molecular weight modifier is not included and the front and rear ends of the solvent-free acrylic composition are maintained at a specific temperature, the reaction tank 1 hour after the start of continuous polymerization It can be seen that the internal pressure of was lowered to 2.0 bar or less, and the continuous operation time of the single screw extrusion reactor corresponded to 2 hours, thereby improving the continuous operation time of the single screw extrusion reactor.

10: single screw extrusion reactor
100: reaction tank
101: screw stirrer
102: stirring shaft
103: stirring wing
110: front end
120: rear end
200: inlet
300: outlet
400: first thermostat
401: first fruit supply unit
402: first fruit discharge unit
500: second thermostat
501: second fruit supply unit
502: second fruit discharge unit

Claims (13)

A method for continuously producing a low molecular weight acrylic resin by continuously polymerizing a non-solvent type acrylic composition containing at least one (meth)acrylate-based monomer and a thermal initiator in a single screw extrusion reactor,
supplying the non-solvent type acrylic composition to a reaction tank through an inlet;
obtaining a low molecular weight acrylic resin by continuously polymerizing the supplied composition; and
Discharging the low molecular weight acrylic resin in the reaction tank through an outlet,
During the continuous polymerization, the temperature of the front end of the reactor is maintained at 90 ° C or more and 200 ° C or less, and the temperature at the rear end of the reactor is maintained at 30 ° C or more and less than 70 ° C,
The continuous polymerization is a method for producing a low molecular weight acrylic resin that is carried out under a pressure of more than 0 bar and less than 5 bar.
The method of claim 1,
The solvent-free acrylic composition is a method for producing a low molecular weight acrylic resin that is supplied to the reaction tank at a supply flow rate of 30 mL / min or more and 400 mL / min or less.
The method of claim 1,
The continuous polymerization is a method for producing a low molecular weight acrylic resin that is carried out for a time of 1 minute or more and 120 minutes or less.
delete The method of claim 1,
During the continuous polymerization, the temperature difference between the front end and the rear end of the reactor is 50 ° C. or more and 150 ° C. or less.
The method of claim 1,
The ratio of the length and diameter of the reaction vessel is 10: 1 or more and 1,000: 1 or less.
The method of claim 1,
The weight average molecular weight of the low molecular weight acrylic resin is 1,000 g / mol or more and 150,000 g / mol or less.
The method of claim 1,
The polydispersity index of the low molecular weight acrylic resin is a method for producing a low molecular weight acrylic resin that is 5 or less.
The method of claim 1,
The glass transition temperature of the low molecular weight acrylic resin is -50 ℃ or more and less than 100 ℃ method of producing a low molecular weight acrylic resin.
The method of claim 1,
The conversion rate of the low molecular weight acrylic resin is 20% or more and 100% or less, and the conversion rate is a method for producing a low molecular weight acrylic resin that is defined by the following general formula 1:
[Formula 1]
C = B/A × 100
In Formula 1, A means the weight (g) of the low molecular weight acrylic resin, B means the weight (g) of the dried material of the low molecular weight acrylic resin, and C means the conversion rate (%).
The method of claim 1,
The (meth) acrylate-based monomer is an alkyl group-containing (meth) acrylate-based monomer, a cycloalkyl group-containing (meth) acrylate-based monomer, and a polar functional group-containing (meth) acrylate-based monomer that is at least one selected from low molecular weight acrylic-based Resin manufacturing method.
The method of claim 1,
The thermal initiator is a method for producing a low molecular weight acrylic resin that is at least one selected from the group consisting of azo-based thermal initiators and peroxy-based thermal initiators.
The method of claim 1,
The solvent-free acrylic composition is a method for producing a low molecular weight acrylic resin that does not contain a molecular weight modifier.

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