KR102231225B1 - Styrene resin with heat-resistance and method for producing the same - Google Patents

Abstract

The present invention relates to a heat-resistant styrene-based resin and a method for manufacturing the same, and by adding a small amount of methacrylamide (MAAM) in addition to the existing aromatic vinyl monomer and unsaturated nitrile monomer, the molecular weight and polymerization conversion rate are maintained at the existing excellent level. It provides a heat-resistant styrene resin and a method of manufacturing the same, which can greatly improve heat resistance and impact resistance.

Description

Heat-resistant styrene resin and its manufacturing method {STYRENE RESIN WITH HEAT-RESISTANCE AND METHOD FOR PRODUCING THE SAME}

The present invention relates to a heat-resistant styrene-based resin and a method for producing the same, in which heat resistance and impact resistance are greatly improved by adding a small amount of methacrylamide (MAAM) as a monomer.

Acrylonitrile-butadiene-styrene (ABS) thermoplastic resin has excellent chemical resistance such as impact resistance, processability, surface gloss, chemical resistance, and physical properties such as molding processability, so it is widely used in various office equipment, electrical and electronic parts, interior and exterior materials of automobiles. .

Styrene-acrylonitrile (SAN) resin, which is the base resin of the general-purpose acrylonitrile-butadiene-styrene resin, has excellent chemical resistance, mechanical properties, and transparency, and has excellent compatibility with ABS, but has a defect in that it is not excellent in heat resistance. It has a disadvantage that it is difficult to apply to heat-resistant ABS used under high temperature.

In order to compensate for the disadvantages of the styrene-acrylonitrile resin, as a method of improving the heat resistance of the styrene-acrylonitrile resin, there is a method of applying a monomer such as α-methylstyrene, vinyltoluene, t-butyl styrene, and in particular α -The method of introducing methylstyrene monomer is mainly used.

However, due to the low depolymerization temperature of the α-methyl styrene, polymerization must be performed at a temperature lower than the polymerization temperature of the conventional styrene-based copolymer, so that the polymerization rate and polymerization conversion rate are significantly lowered. The low polymerization conversion rate directly leads to a decrease in productivity, which is a major obstacle to industrial applications.

In order to solve this problem, in the conventional method, the reaction residence time was lengthened or the method of using an excessive amount of initiator was used, but the disadvantage of causing a decrease in productivity or the color of the final product was poor, and the excessive use of the initiator has a low molecular weight. Another problem occurred that the heat-resistant ABS physical properties and chemical resistance were deteriorated.

Accordingly, the inventors of the present invention have studied to solve the polymerization conversion rate decrease and molecular weight decrease that occur when the residence time is reduced to improve productivity in order to easily apply the heat-resistant resin to the industry. As a monomer, the existing aromatic vinyl monomer and unsaturated By adding a small amount of methacrylamide (MAAM) in addition to the nitrile monomer, we invented a heat-resistant styrene resin and a method for manufacturing the same, which can greatly improve heat resistance and impact resistance while maintaining the existing excellent levels of molecular weight and polymerization conversion rate. Became.

US 5,116,907 A (1992.05.26)

The present invention was devised to solve the problems of the prior art, and the problem to be solved of the present invention is by adding a small amount of methacrylamide (MAAM) in addition to the existing aromatic vinyl monomer and unsaturated nitrile monomer as a monomer, And a heat-resistant styrene resin that can greatly improve heat resistance and impact resistance while maintaining the existing excellent level of polymerization conversion rate. It is to provide a manufacturing method.

Another problem to be solved of the present invention is a heat-resistant styrenic resin and a heat-resistant resin molded article comprising a small amount of methacrylamide (MAAM)-derived units in addition to units derived from aromatic vinyl monomers and units derived from unsaturated nitrile monomers. Is to provide.

The present invention is to solve the above problems,

1) performing a polymerization reaction by adding a polymerization initiator to a mixture solution containing a reaction solvent and a monomer mixture containing an aromatic vinyl monomer, an unsaturated nitrile monomer, and a methacrylamide monomer; And

2) It provides a heat-resistant styrene-based resin manufacturing method comprising the step of devolatilizing the polymerization product generated by the polymerization reaction.

In addition, the present invention provides a heat-resistant styrene-based resin comprising an aromatic vinyl-based monomer-derived unit, an unsaturated nitrile-based monomer-derived unit, and a methacrylamide monomer-derived unit, and a heat-resistant styrene-based resin molded article prepared therefrom.

The heat-resistant styrenic resin and its manufacturing method according to the present invention are effective in that by adding a small amount of methacrylamide (MAAM), the molecular weight and polymerization conversion rate can be significantly improved while maintaining the existing excellent level. There is.

Therefore, the heat-resistant styrene-based resin and a resin molded article including the same can be widely applied to various industrial fields requiring the same.

Hereinafter, the present invention will be described in more detail to aid understanding of the present invention. At this time, terms or words used in the present specification and claims should not be construed as being limited to a conventional or dictionary meaning, and the inventor appropriately defines the concept of the term in order to describe his own invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that it can be done.

Heat-resistant styrene-based resin manufacturing method according to an embodiment of the present invention,

1) performing a polymerization reaction by adding a polymerization initiator to a mixture solution containing a reaction solvent and a monomer mixture containing an aromatic vinyl monomer, an unsaturated nitrile monomer, and a methacrylamide monomer; And

2) It characterized in that it comprises the step of devolatilizing the polymerization product produced by the polymerization reaction.

Hereinafter, each step of the method for manufacturing a heat-resistant styrene-based resin according to an embodiment of the present invention will be described in detail.

Step 1)

The step 1) according to an embodiment of the present invention is a polymerization reaction step for preparing an aromatic vinyl-unsaturated nitrile-based copolymer, wherein the polymerization reaction is a reaction solvent and an aromatic vinyl-based monomer, an unsaturated nitrile-based monomer, and methacrylamide. It is characterized in that it is carried out by adding a polymerization initiator to a mixed solution containing a monomer mixture containing a monomer.

In particular, the monomer mixture used in the polymerization reaction of the present invention is characterized in that it contains a methacrylamide monomer of the following formula (1) in addition to an aromatic vinyl-based monomer and an unsaturated nitrile-based monomer.

[Formula 1]

In order to improve the heat resistance of the conventional styrene-acrylonitrile resin, the polymerization rate and the polymerization conversion rate are significantly lowered due to the polymerization temperature lowered due to the introduction of α-methylstyrene, and in order to solve this problem, the reaction residence time is increased, or Although the method of using an excessive amount of the initiator was used, another problem that the physical property balance of the heat-resistant styrene-based resin was collapsed due to a decrease in productivity or a decrease in molecular weight occurred.The method for preparing a heat-resistant styrene-based resin of the present invention is a monomer. The above problem was solved by adding a small amount of acrylamide (MAAM) to prepare a heat-resistant styrene-based copolymer in which an aromatic vinyl-based monomer, an unsaturated nitrile-based monomer, and a methacrylamide monomer were copolymerized.

Specifically, by adding the methacrylamide monomer, it was possible to obtain an effect of greatly improving heat resistance and impact resistance while maintaining the existing excellent levels of molecular weight and polymerization conversion rate.

Meanwhile, the effect of using the methacrylamide monomer can be maximized when it is used in an appropriate ratio with an aromatic vinyl-based monomer and an unsaturated nitrile-based monomer.

Therefore, the monomer mixture used in the polymerization reaction of the present invention is

60 to 70 parts by weight of an aromatic vinyl monomer; 25 to 35 parts by weight of an unsaturated nitrile-based monomer; And 1 to 5 parts by weight of a methacrylamide monomer.

When the methacrylamide monomer is used in an excessively small amount of less than 1 part by weight, there may be a problem that the heat resistance and impact resistance are greatly reduced, and when the methacrylamide monomer is used in an excessive amount exceeding 5 parts by weight, the methacrylamide monomer is mixed There may be a problem that the polymerization reaction cannot be performed because it is present in an insoluble state in the solution.

Meanwhile, in an embodiment of the present invention, the aromatic vinyl-based monomer is selected from the group consisting of styrene, α-methylstyrene, p-bromostyrene, p-methylstyrene, p-chlorostyrene, and o-bromostyrene. It is possible to use one or more of which are used, and more specifically, α-methylstyrene (AMS) may be used to improve heat resistance.

In addition, the aromatic vinyl-based monomer is characterized in that it contains 60 to 70 parts by weight, more specifically 65 to 70 parts by weight based on the total weight of the monomer mixture. When the aromatic vinyl monomer is contained in an amount of less than 60 parts by weight, heat resistance is lowered and yellowing is easy when heated, and when it is included in an amount exceeding 70 parts by weight, the inclusion of the unsaturated nitrile monomer is relatively reduced, and the polymerization conversion rate and There is a problem with a low molecular weight, which is not preferable.

In one embodiment of the present invention, the unsaturated nitrile-based monomer is at least one selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile, and α-chloroacrylonitrile. It may be used, and more specifically, acrylonitrile (AN) may be used.

In addition, the unsaturated nitrile-based monomer is characterized in that it contains 25 to 35 parts by weight, more specifically 25 to 30 parts by weight based on the total weight of the monomer mixture. When the unsaturated nitrile monomer is included in an amount of less than 25 parts by weight, there is a problem that the polymerization conversion rate and molecular weight are lowered, and when it is included in an amount exceeding 35 parts by weight, a color problem occurs when three or more unsaturated nitrile monomers are combined. It may occur, which is not desirable.

In an embodiment of the present invention, the reaction solvent may be one or more selected from the group consisting of ethylbenzene, toluene, dimethylacetamide, xylene, and methylethylketone, and more specifically, toluene or dimethylacetamide. Can be used.

The content of the reaction solvent is preferably 2 to 20 parts by weight based on 100 parts by weight of the monomer mixture. If the content of the reaction solvent is less than 2 parts by weight, the viscosity may increase rapidly as the reaction proceeds, and if it exceeds 20 parts by weight, the polymerization conversion rate may decrease, which is not preferable.

In an embodiment of the present invention, the polymerization initiator of the polymerization reaction is dicumyl peroxide, 2,2-bis(4,4-di-t-butylperoxycyclohexane)propane, 1,1-bis(t -Butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane and 1,1-bis (t-hexylperoxy) selected from the group consisting of cyclohexane One or more types may be used, and more specifically, 1,1-bis(t-butylperoxy)cyclohexane or 2,2-bis(4,4-di-t-butylperoxycyclohexane)propane may be used. I can.

The polymerization initiator may be added in an amount of 0.1 parts by weight to less than 0.5 parts by weight based on 100 parts by weight of the total monomer mixture. If the polymerization initiator is added in an amount of less than 0.1 parts by weight, there may be a problem of lowering the conversion rate, and when the polymerization initiator is added in an amount exceeding 0.5 parts by weight, there may be a problem that the molecular weight is too low.

The polymerization reaction may be performed in a temperature range of 110°C to 114°C. When the temperature of the polymerization reaction is controlled within the above range, it is possible to reduce the generation of oligomers generated during polymerization, thereby helping to improve heat resistance.

Meanwhile, the polymerization reaction may be a continuous bulk polymerization, and when the bulk polymerization is a continuous bulk polymerization, the polymerization reaction may include at least one polymerization step. Here, “at least one” may represent at least one or more than one. In addition, when the bulk polymerization is a continuous bulk polymerization, the number of polymerization steps may be appropriately adjusted as desired, and the polymerization conditions of each polymerization step may be different or the same.

In addition, the method for producing a heat-resistant styrene resin of the present invention is characterized in that the polymerization conversion rate is 59 to 62% excellent. If the polymerization conversion rate is less than 59%, the content of the unreacted monomer is high, resulting in a problem that productivity is lowered, and it takes a long time to recover the unreacted. If the polymerization conversion rate exceeds 62%, the process conditions become severe and control of the reaction is difficult. It is difficult and there is a problem that gel formation may increase, which is not preferable.

On the other hand, the polymerization reaction may be performed by adding a molecular weight modifier as needed.

The molecular weight modifier is for controlling the viscosity of the resin, the size of the particles, and the distribution of the particles by controlling the molecular weight of the copolymer to be prepared, n-dodecyl mercaptan, n-amyl mercaptan, t-butyl At least one selected from the group consisting of mercaptan, t-dodecyl mercaptan, n-hexyl mercaptan, n-octyl mercaptan, and n-nonyl mercaptan may be used, and the molecular weight modifier is 100 parts by weight of the monomer mixture. It is preferably about 0.01 to 1.0 parts by weight. If the content of the molecular weight modifier is less than 0.01 parts by weight, it is disadvantageous in the process due to excessive viscosity increase, resulting in a decrease in the properties of the resin, and if it exceeds 1.0 parts by weight, there may be a problem that the polymerization reaction does not proceed and the balance of the properties of the final product does not appear .

Step 2)

The step 2) according to an embodiment of the present invention is a step for separating a polymer, characterized in that the polymer is separated by volatilizing an unreacted monomer and a solvent from the polymerization product produced by the polymerization reaction in a volatilization tank. .

Specifically, the polymerization product polymerized through step 1) is then added to a volatilization tank to which a heat exchanger is attached and maintains a temperature of 200 to 250 °C and a vacuum degree of 25 torr or less to volatilize unreacted monomers and solvents. It is possible to obtain a heat-resistant styrene-based copolymer comprising a unit derived from an aromatic vinyl-based monomer from which the reaction monomer and the reaction solvent have been removed, a unit derived from an unsaturated nitrile-based monomer, and a unit derived from a methacrylamide monomer.

In the present invention, the unreacted monomer and the reaction solvent volatilized in the polymer separation step may be recovered by condensation and then re-introduced to the polymerization step of step 1).

In addition, the copolymer obtained above may be processed while passing through a transfer pump and an extruder afterwards to be prepared in the form of pellets.

In addition, the present invention provides a heat-resistant styrene resin comprising a unit derived from an aromatic vinyl-based monomer, a unit derived from an unsaturated nitrile-based monomer, and a unit derived from a methacrylamide monomer.

Specifically, the heat-resistant styrene-based resin of the present invention includes 65 to 70 parts by weight of units derived from an aromatic vinyl-based monomer; 25 to 30 parts by weight of units derived from unsaturated nitrile-based monomers; And by including 1 to 5 parts by weight of a unit derived from a methacrylamide monomer, the molecular weight and polymerization conversion rate can exhibit the effect of greatly improving heat resistance and impact resistance while maintaining an existing excellent level.

In addition, the heat-resistant styrenic resin has a glass transition temperature of 130 to 138 °C and a weight average molecular weight (Mw) of 75,000 to 78,000, and exhibits excellent heat resistance and excellent molecular weight related to fluidity.

In addition, the present invention provides a heat-resistant styrene-based resin molded article manufactured from the heat-resistant styrene-based resin of the present invention. On the other hand, the heat-resistant styrene-based resin molded article adds one or more additives selected from the group consisting of heat-resistant styrene-based resins and, if necessary, heat stabilizers, lubricants, antioxidants, light stabilizers, flame retardants, antistatic agents, colorants, fillers, and ultraviolet stabilizers. Can be included as.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

Example One

To prepare a monomer mixture comprising 70 parts by weight of α-methyl styrene, 29 parts by weight of acrylonitrile, and 1 part by weight of methacrylamide, and 3 parts by weight of toluene are mixed therein, and 1,1- After 0.2 parts by weight of bis(t-butylperoxy)cyclohexane was added to prepare a polymerization reaction solution, the solution was continuously added to a series of reactors at a temperature of 112°C by continuous polymerization to carry out a polymerization reaction. The prepared polymerization product was transferred to a devolatilization tank, and the unreacted monomer and the reaction solvent were recovered and removed under a temperature of 235° C. and a pressure of 20.6 torr to prepare a heat-resistant styrene resin in the form of a pellet.

Example 2 to 4 and Comparative example 1 to 4

Each condition of Example 1 was changed as shown in Table 1 below to prepare heat-resistant styrene resins of Examples 2 to 4 and Comparative Examples 1 to 4.

Experimental example

The glass transition temperature (Tg), weight average molecular weight (Mw), and polymerization conversion rate (%) of each heat-resistant styrene resin prepared in Examples 1 to 4 and Comparative Examples 1 to 4 were measured, and the results are shown in Table 1 below. Shown in.

1) Glass transition temperature (Tg, ℃)

The glass transition temperature was measured using a Q20 DSC manufactured by TA instruments for each heat-resistant styrene resin.

2) Weight average molecular weight (Mw, g/mol)

The weight average molecular weight was dissolved by adding 20 ml of THF (tetrahydrofuran) to 0.02 g of each heat-resistant styrene resin using GPC (Gel Permeation Chromatography, Waters 2410 RI Detector, 515 HPLC pump. 717 Auto Sampler), and filtered through a 0.45 µm filter Each sample was made by putting it in a GPC vial (4 ml). The solvent (THF) was injected at a rate of 1.0 ml/min from 1 hour before the measurement, and the measurement time was 25 minutes, the injection volume was 150 μl, the flow rate was 1.0 ml/min, isocratic pump mode, and measured under the conditions of 40 with an RI detector. At this time, it was calibrated using the PS standard.

3) polymerization conversion rate (%)

For the polymerization conversion rate, the initial mass of each reactant before polymerization of each heat-resistant styrene-based resin is measured, and the weight based on the monomer minus the content of the solvent is recorded, and the weight of each heat-resistant styrene-based resin generated after the polymerization reaction is measured, and then the polymerization. It was measured as the ratio of the weight of the previous monomer and the weight of the heat-resistant styrene resin after polymerization.

Monomer content Heat-resistant styrenge resin properties AMS AN MAAM Tg(℃) Mw(g/mol) Polymerization conversion rate (%) Example 1 70 29 One 130.7 78,000 61.9 Example 2 68 29 3 133.8 77,200 61.5 Example 3 66 29 5 137.6 76,300 60.9 Example 4 70 27 3 135.2 75,600 59.8 Comparative Example 1 71 29 - 127.5 78,400 62.1 Comparative Example 2 61 29 10 Insoluble Comparative Example 3 72 23 5 136.9 68,100 49.6 Comparative Example 4 77 23 - 131.0 70,200 50.9

As shown in Table 1, the heat-resistant styrene-based resin prepared by the production method of the present invention of Examples 1 to 4 was compared with the heat-resistant styrene-based resin of Comparative Examples 1 and 4 in which methacrylamide was not added. Thus, it was confirmed that the glass transition temperature was high and the heat resistance was excellent.

On the other hand, in Comparative Example 2 in which an excess of methacrylamide was added, there was a problem that the excess methacrylamide was not dissolved in the solvent.

In addition, Comparative Example 3, in which methacrylamide in the same amount as in Example 3 was added, was excellent in heat resistance as viewed from the glass transition degree, but it was confirmed that the polymerization conversion rate was not good. This is due to the fact that α-methyl styrene is added in excess of the range of the present invention and acrylonitrile is added in a smaller amount than the range of the present invention. When used as, it means that heat resistance and impact resistance can be greatly improved while maintaining an existing excellent level of molecular weight and polymerization conversion rate desired by the present invention.

The above description of the present invention is for illustrative purposes only, and those of ordinary skill in the art to which the present invention pertains will be able to understand that other specific forms can be easily modified without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative and non-limiting in all respects.

Claims (14)

1) performing a bulk polymerization reaction by adding a polymerization initiator to a mixture solution containing a reaction solvent and a monomer mixture including an aromatic vinyl-based monomer, an unsaturated nitrile-based monomer, and a methacrylamide monomer; And
2) A method for producing a heat-resistant styrene-based resin comprising the step of devolatilizing the polymerization product produced by the bulk polymerization reaction.
The method of claim 1,
The monomer mixture is
60 to 70 parts by weight of an aromatic vinyl monomer;
25 to 35 parts by weight of an unsaturated nitrile-based monomer; And
Heat-resistant styrene-based resin manufacturing method comprising 1 to 5 parts by weight of a methacrylamide monomer.
The method of claim 1,
The polymerization initiator is a heat-resistant styrene-based resin manufacturing method, characterized in that it contains 0.1 to 0.5 parts by weight.
The method of claim 1,
The bulk polymerization reaction is a heat-resistant styrene-based resin production method, characterized in that by the continuous bulk polymerization reaction carried out in a temperature range of 110 to 114 ℃.
The method of claim 1,
The heat-resistant styrene-based resin production method, characterized in that the polymerization conversion rate of the heat-resistant styrene-based resin production method is 59 to 62%.
The method of claim 1,
The aromatic vinyl-based monomer is at least one selected from the group consisting of styrene, α-methylstyrene, p-bromostyrene, p-methylstyrene, p-chlorostyrene and o-bromostyrene. Resin manufacturing method.
The method of claim 1,
The unsaturated nitrile-based monomer is at least one selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile, and α-chloroacrylonitrile. .
The method of claim 1,
The reaction solvent is at least one selected from the group consisting of ethylbenzene, toluene, dimethylacetamide, xylene, and methyl ethyl ketone.
The method of claim 1,
The devolatilization of step 2) is performed under a temperature range of 200° C. to 250° C. and a pressure condition of 25 torr or less.
The method of claim 1,
Condensing the unreacted monomer and solvent volatilized in step 2) and reintroducing the polymerization reaction in step 1).
Including a unit derived from an aromatic vinyl monomer, a unit derived from an unsaturated nitrile monomer, and a unit derived from a methacrylamide monomer,
The glass transition temperature is 130 to 138 °C,
Heat-resistant styrenic resin having a weight average molecular weight (Mw) of 75,000 to 78,000 g/mol.
The method of claim 11,
The heat-resistant styrene resin is
65 to 70 parts by weight of units derived from aromatic vinyl monomers;
25 to 30 parts by weight of units derived from unsaturated nitrile-based monomers; And
Heat-resistant styrenic resin comprising 1 to 5 parts by weight of units derived from methacrylamide monomers.
delete A heat-resistant styrene-based resin molded article manufactured from the heat-resistant styrene-based resin of claim 11.