KR20230073022A - A composition, eco-friendly polystyrene foam having excellent thermal insulation property and method for manufactureing the same - Google Patents

Abstract

The present application relates to polystyrene foam with excellent thermal insulation properties. Specifically, the present application relates to eco-friendly extruded polystyrene foam manufactured using an eco-friendly foaming agent and having excellent thermal insulation properties, and a manufacturing method thereof. The manufacturing method of the polystyrene foam comprises: a foaming agent injection step of: adding a methyl formate foaming agent to a melt containing a polystyrene resin under conditions of a pressure of 1400 psi or more and a temperature of 215℃ or less; and an extrusion step of extruding the mixture containing the melt and methyl formate.

Description

A composition, eco-friendly polystyrene foam having excellent thermal insulation property and method for manufacturing the same}

The present application relates to a composition, an eco-friendly polystyrene foam having excellent thermal insulation properties, and a manufacturing method thereof. Specifically, the present application is a foaming composition comprising an environmentally friendly foaming agent; a low-density polystyrene foam prepared using the foaming composition and having excellent thermal insulation properties; and a manufacturing method thereof.

A foam board is required to have low density and excellent thermal insulation performance. However, when the density of the styrene foam is designed to be too low, it is not easy to manufacture polystyrene foam having a low density and excellent heat insulation performance at the same time, such as a problem in that the heat insulation performance of the styrene foam becomes poor.

Meanwhile, typical foaming agents used in the prior art include foaming agents such as so-called carbon dioxide foaming agents and hydrochlorofluorocarbons (HCFCs). However, the hydrochlorofluorocarbon blowing agent is a strong ozone layer depleting agent, and its use is already banned in many countries. And, in case of carbon dioxide blowing agent, compared to hydrochlorofluorocarbon blowing agent, solubility in polystyrene resin is low. Therefore, high pressure is required when mixing the polystyrene resin and the carbon dioxide foaming agent, and practical use is difficult without replacing equipment (eg, an extruder, etc.). Furthermore, due to the characteristics of carbon dioxide having a high degree of activity, such as high effective diffusion rate and high permeability, carbon dioxide derived from the carbon dioxide foaming agent does not remain in the foam board and is easily replaced by air, thereby increasing the thermal conductivity of the finally manufactured styrene foam. there is a problem with

Therefore, a technique for providing a polystyrene foam capable of improving the above-described problems of the prior art is required.

One object of the present application is to provide a polystyrene foam having low density and excellent thermal insulation performance.

Another object of the present application is to provide an environmentally friendly polystyrene foam capable of improving ozone depletion and global warming problems.

Another object of the present application is to provide a polystyrene foam excellent in fairness and economy.

The above and other objects of the present application can all be solved by the present application described in detail below.

In one example relating to the present application, the present application relates to a method for manufacturing polystyrene foam.

Specifically, the method,

A foaming agent input step of injecting methyl formate, a foaming agent, into a melt containing a polystyrene resin at a pressure of 1400 psi or more and a temperature of 215° C. or less; and

An extrusion step (or molding step) of extruding a mixture containing the melt and methyl formate;

includes

In relation to the above manufacturing method, the step of introducing a foaming agent is a step of injecting a foaming agent into a polystyrene melt containing polystyrene as a main component. At this time, the molten material means that the polystyrene resin or the like is melted at a high temperature and included in a viscous state.

Although not particularly limited, the melt may be formed or present inside the extruder, for example.

In the specific example of the present application, a methyl formate foaming agent is added (or added) to the melt containing the polystyrene resin.

In the prior art, a foaming composition comprising a blowing agent such as hydrofluorocarbon (HFC), hydrochlorofluorocarbon (HCFC), or hydrofluoroolefin (HFO) has been used. However, since these substances are known to destroy the ozone layer, their use should be limited, and if used, the amount should be reduced. For example, HCFC-141B and the like are already banned substances in developed countries. However, methyl formate used in the present application does not have the above environmental restrictions.

In addition, since the methyl formate blowing agent has a boiling point similar to that of conventional blowing agents, it provides an advantage of not needing to significantly change an existing process (providing process convenience). And, methyl formate has about 2 to 4 times higher foaming power than conventional foaming agents such as HCFC foaming agents. Furthermore, in the case of a cost calculated as a unit price per kg relative to the molecular weight of the blowing agent, the methyl formate blowing agent is about half cheaper than conventional blowing agents such as HCFC blowing agents. That is, compared to the conventional foaming agent, the methylformate foaming agent is a foaming agent that can be applied without significantly changing the existing process, provides high foaming power, and can reduce the cost of purchasing the foaming agent.

Additionally, methylformate blowing agents have the advantage of providing good solubility. For example, in the case of carbon dioxide foaming agent, the solubility in polystyrene resin is known to be about 1450 mg/L, but the solubility of methyl formate is about 3000 mg/L. Considering the miscibility or compatibility with polystyrene resin, it is difficult to use an excessive amount of carbon dioxide blowing agent, and for this reason, even if the carbon dioxide blowing agent is applied to the production of polystyrene foam, the prior art hydrofluorocarbon (HFC), hydrochlorination It has no choice but to depend on substances such as fluorocarbons (HCFCs) and hydrogen fluoroolefins (HFOs). On the other hand, since the methyl formate foaming agent has excellent miscibility or compatibility with polystyrene, it can provide a significant part of the foaming effect. As a result, the content of a conventional blowing agent known to destroy the ozone layer can be greatly reduced even if it is not used or used.

In one example, the step of introducing the foaming agent may be a step performed by injecting a methyl formate foaming agent into the melt under a pressure condition of 1450 psi or more. Specifically, the pressure condition in the step of introducing the blowing agent may be 1500 psi or more, 1550 psi or more, 1600 psi or more, 1650 psi or more, 1700 psi or more, or 1750 psi or more, and the upper limit is, for example, 1800 psi or less, 1750 psi or less, 1700 psi or less, 1650 psi or less, 1600 psi or less, 1550 psi or less or 1500 psi or less.

In one example, the step of introducing the foaming agent may be a step performed by adding a methyl formate foaming agent to the melt at a temperature of 215 °C or lower. Specifically, the temperature condition in the step of introducing the blowing agent is 210 ℃ or less, 205 ℃ or less, 200 ℃ or less, 195 ℃ or less, 190 ℃ or less, 185 ℃ or less, 180 ℃ or less, 175 ℃ or less, 170 ℃ or less or 165 ℃ The lower limit may be, for example, 160 ° C or higher, 165 ° C or higher, 170 ° C or higher, 175 ° C or higher, 180 ° C or higher, 185 ° C or higher, 190 ° C or higher, 195 ° C or higher, 200 ° C or higher, 205 ° C or higher. or 210 °C or higher.

As confirmed in the experimental example below, when the process of introducing a foaming agent satisfies the above conditions, stable mixing and dispersion between melts is easy, an appropriate level of extrusion can be secured, low density (lightness) and excellent It is advantageous to impart heat insulating properties to styrene foam.

Although not particularly limited, the methyl formate foaming agent may be added to the melt after being introduced into an extruder in a liquid state under the above-described pressure and temperature conditions for the injection of the foaming agent. Then, it can change its phase to a gas.

In one example, the methyl formate foaming agent may be introduced (or added) to the melt in an amount of 3.0 parts by weight or more relative to 100 parts by weight of the polystyrene resin contained in the melt. Specifically, the input content of the methyl formate is, for example, 3.5 parts by weight or more, 4.0 parts by weight or more, 4.5 parts by weight or more, 5.0 parts by weight or more, 5.5 parts by weight or more, 6.0 parts by weight or more, 6.5 parts by weight or more , 7.0 parts by weight or more, 7.5 parts by weight or more, 8.0 parts by weight or more, 8.5 parts by weight or more, 9.0 parts by weight or more, 9.5 parts by weight or more, or 10.0 parts by weight or more. If the content of the methyl formate blowing agent is less than the above range ( For example, in the case of 2.0 parts by weight or less), the thermal conductivity is poor because the degree of foaming is insignificant, and the function of the foam is not exhibited while the density is greatly increased.

In one example, the content of the methyl formate foaming agent may be 15.0 parts by weight or less relative to 100 parts by weight of the polystyrene resin. Specifically, the upper limit may be, for example, 14 parts by weight or less, 13 parts by weight or less, 12 parts by weight or less, 11 parts by weight or less, 10 parts by weight or less, 9 parts by weight or less, 8 parts by weight or less, or 7 parts by weight or less. there is. When the content of the methyl formate foaming agent exceeds the above range, the degree of foaming may be appropriate or sufficient, but the foam greatly shrinks as the density decreases, and as a result, the function of the foam is not exhibited.

A specific type of the polystyrene included in the melt is not particularly limited. For example, polystyrene (PS: Polysyrene) known to be used in an extrusion process as a thermoplastic polymer may be used without limitation in preparing the polystyrene foam of the present application.

In one example, the weight average molecular weight of the polystyrene may be determined in consideration of extrusion processability or heat resistance of the resin. Specifically, the weight average molecular weight (Mw) of the polystyrene may be 100,000 to 400,000. Specifically, the lower limit of the weight average molecular weight of the polystyrene may be, for example, 150,000 or more, 200,000 or more, or 25,000 or more, and the upper limit may be, for example, 350,000 or less, 300,000 or less, 250,000 or less, 200,000 or less, or 150,000 or less. . In this case, the weight average molecular weight may be a weight average molecular weight in terms of polystyrene measured by GPC.

In some cases, the melt may further include recycled polystyrene or polystyrene derived therefrom. That is, when preparing the melt, recycled polystyrene may be melted together with a general polymerized polystyrene resin. However, in the case of recycled components, open cells may be formed to deteriorate the thermal insulation properties of the foam, and the polystyrene foam manufacturing process may be unstable due to non-uniform quality of recycled products. In view of this, while appropriately adjusting the process conditions, for example, 50 parts by weight or less, 40 parts by weight or less, 30 parts by weight or less, 20 parts by weight or less, or 10 parts by weight or less based on 100 parts by weight of the polystyrene resin (total) In sub-part amounts, recycled polystyrofoam or polystyrene derived therefrom may be used. The content of recycled polystyrene is not particularly limited, but recycled polystyrofoam or polystyrene derived therefrom may be used in an amount of, for example, 0.1 part by weight or more.

In one example, the melt may include at least one selected from a flame retardant and a nucleating agent.

In one example, a phosphorus-based compound and/or a halogen-based compound may be used as the flame retardant. Although not particularly limited, the flame retardant may be, for example, a brominated flame retardant. The bromine (Br) component included in the bromine-based flame retardant penetrates into the expanded polystyrene foam board and generates an incombustible gas to cause fire extinguishing. As the brominated flame retardant, those that can be mainly used for expanded polystyrene foam (EPS) or extruded polystyrene foam (XPS) based on polystyrene may be used. According to the specific example of the present application, hexabromocyclododecane, bromide At least one selected from the group consisting of minated epoxy oligomer, TBBA-aryl ether, tribromophenyl aryl ether and tetrabromocyclooctane may be used as the flame retardant.

Although not particularly limited, the flame retardant may be injected into an extruder in the form of a powder, and then mixed with the polystyrene resin and melted at a predetermined temperature. Alternatively, the flame retardant may be mixed with the polystyrene resin in the form of pellets and introduced into an extruder as a master batch.

In one example, the flame retardant may be included in the melt in the range of 0.5 to 15 parts by weight based on 100 parts by weight of the polystyrene resin. Specifically, the content of the flame retardant may be 1 part by weight or more, 2 parts by weight or more, 3 parts by weight or more, 4 parts by weight or more or 5 parts by weight or more, and the upper limit is, for example, 14 parts by weight or less, 13 parts by weight or less. 12 parts by weight or less, 11 parts by weight or less, 10 parts by weight or less, 9 parts by weight or less, 8 parts by weight or less, 7 parts by weight or less, 6 parts by weight or less, or 5 parts by weight or less. When the amount of the flame retardant is less than the above range, the flammability of the styrene foam may be deteriorated, such that the manufactured extruded styrene foam does not satisfy the flammability standard specified in KS M 3808. In addition, when the content of the flame retardant exceeds the above range, material properties such as strength and thermal conductivity of the foam may be deteriorated, and expensive flame retardants are excessively used, which is uneconomical.

In one example, the nucleating agent is talc, silica, alumina, zeolite, calcium carbonate, magnesium carbonate, barium sulfate, zinc oxide, titanium oxide, aluminum hydroxide, magnesium hydroxide, mica, montmorronite, carbon particles, glass It may include one or more selected from fibers and carbon tubes. The nucleating agent can supplement the thermal insulation properties of polystyrene foam and reduce or uniformize the size of the foamed cells in the process of preparing the expandable polystyrene polymer according to the extrusion method. In addition, the nucleating agent can improve the causticity and creep property of the polymer at high temperature, and improve dimensional stability and matting property.

In one example, the nucleating agent may have a size ranging from 3 to 6 μm. At this time, the size is the average particle size of the nucleating agent, and may be the D50 (number average) size measured by a particle size analyzer. When the size of the particles is less than the above range, the matting effect is low, and when the size exceeds the above range, surface roughness increases and open cells may occur in the foam.

Although not particularly limited, the nucleating agent may be introduced into an extruder in the form of a powder, and then mixed with the polystyrene resin and melted at a predetermined temperature. Alternatively, the nucleating agent may be mixed with the polystyrene resin in the form of pellets and introduced into an extruder as a master batch.

In one example, considering the function of the nucleating agent as described above, the nucleating agent may be included in the melt in the range of 0.1 to 10 parts by weight based on 100 parts by weight of the polystyrene resin. Specifically, the lower limit of the content of the nucleating agent may be, for example, 0.5 parts by weight or more, 1.0 parts by weight or more, 1.5 parts by weight or more, 2.0 parts by weight or more, 2.5 parts by weight or more or 3.0 parts by weight or more, and the upper limit is eg For example, it may be 9 parts by weight or less, 8 parts by weight or less, 7 parts by weight or less, 6 parts by weight or less, or 5 parts by weight or less.

In one example, the step of introducing the foaming agent may be a step performed by injecting (or adding) a different type of foaming agent different from the methyl formate foaming agent into the melt together with the methyl formate foaming agent. . At this time, adding together does not mean a point in time, but means that it can be used together as a foaming agent. For example, the methyl formate blowing agent and the heterogeneous blowing agent may be introduced (or added) to the melt at the same time or at the same time.

The type of heterogeneous foaming agent that can be used is not particularly limited. In addition to the methyl formate blowing agent, one or more blowing agents known in the art may be used. For example, hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs) or hydrofluoroolefins (HFOs), etc. may be used, and the use thereof is preferably not prohibited due to environmental pollution problems such as depletion of the ozone layer. may be used. The specific type is also not particularly limited, for example, HFC-245fa (1,1,1,3,3-Pentafluoropropane), HFC-152a (1,1-Difluoroethane) or HFC-134a (1 ,1,1,2-Tetrafluoroethane) and the like can be used, and the HFO blowing agent is, for example, HFO-1233zd (1-Chloro-3,3,3-trifluoropropene) or HFO-1336mz (1,1,1, 4,4,4-Hexafluoro-2-Butene) and the like can be used. Also, two or more of those listed above may be used as the heterogeneous foaming agent.

In one example, the step of adding the blowing agent is to adjust the amount (weight) of the heterogeneous blowing agent used in combination with the methyl formate blowing agent in a small amount compared to the methyl formate blowing agent. may be a step. As described above, since the methyl formate blowing agent has high miscibility or compatibility with the polystyrene resin, the methyl formate blowing agent may occupy an excessive amount among the total amount of the blowing agent for securing the foaming effect. This can reduce the side effects of conventionally known foaming agents.

In one example, the ratio (W2/W1) of the weight (W2) of the heterogeneous foaming agent to the weight (W1) of the methyl formate foaming agent may be 0.015 to 0.4. Specifically, the lower limit of the ratio may be, for example, 0.050 or more, 0.100 or more, 0.150 or more, 0.200 or more, 0.250 or more, 0.300 or more, or 0.350 or more. In addition, the upper limit of the ratio may be, for example, 0.350 or less, 0.300 or less, 0.250 or less, 0.200 or less, or 0.150 or less. If the ratio (W2 / W1) is less than the above range, foam shrinkage may occur within several hours (within about 1 hour) after the foam is manufactured, and if the ratio exceeds the above range, the insulation properties of the foam are lowered, An open cell may occur in the form. Since open cells increase the thermal conductivity value of the foam, the occurrence or increase of open cells is not suitable for foams requiring low thermal conductivity (thermal insulation).

In one example, the heterogeneous foaming agent may be injected (or added) to the melt in an amount of 0.045 to 6 parts by weight based on 100 parts by weight of the polystyrene resin included in the melt. Specifically, the content of the heterogeneous foaming agent is, for example, 0.05 parts by weight or more, 0.1 parts by weight or more, 0.15 parts by weight or more, 0.2 parts by weight or more, 0.25 parts by weight or more, 0.3 parts by weight or more, 0.35 parts by weight or more. , 0.40 parts by weight or more, 0.45 parts by weight or more, 0.50 parts by weight or more, 0.55 parts by weight or more, 0.60 parts by weight or more, 0.70 parts by weight or more, or 0.80 parts by weight or more. And, the upper limit is 6.0 parts by weight or less, 5.5 parts by weight or less, 5.0 parts by weight or less, 4.5 parts by weight or less, 4.0 parts by weight or less, 3.5 parts by weight or less, 3.0 parts by weight or less, 2.5 parts by weight or less, 2.0 parts by weight or less, It may be 1.5 parts by weight or less or 0.5 parts by weight or less. If the content is out of the above range, the density of the styrene foam increases and the thermal conductivity decreases as the thermal conductivity increases, and open cells occur on the surface of the foam, causing problems such as the difficulty of the styrene foam board having a flat plate shape. can happen

Although not particularly limited, the heterogeneous foaming agent may be added to the melt by being introduced into an extruder or the like in a liquid state under the above-described pressure and temperature conditions for introducing the foaming agent. Then, it can change its phase to a gas.

According to an embodiment of the present application, the method includes an extrusion step of extruding a mixture including the melt and the methyl formate.

Although not particularly limited, the extrusion may be performed in an extruder in which a melt into which a foaming agent is injected is stored. Alternatively, molding may be performed after the molten material including the foaming agent is transferred from an extruder (eg, the first extruder) in which the foaming agent is injected into the melt to another extruder (eg, the second extruder). The method of using the extruder is not particularly limited and can be appropriately adjusted by those skilled in the art.

The extrusion step may be adjusted in consideration of the shape and surface characteristics of the foamed pores.

In one example, the extruding step may be performed under a pressure of 800 psi or more and a temperature of 130 °C or less.

In one example, the extruding step may be performed under pressure conditions of 850 psi or more, 900 psi or more, 950 psi or more, 1000 psi or more or 1050 psi or more, and the upper limit is, for example, 1100 psi or less, 1050 psi or less, 1000 psi or less, 950 psi or less, 900 psi or less or 850 psi or less.

In one example, the extruding step may be performed at 125 °C or less, 120 °C or less, 115 °C or less, 110 °C or less, 105 °C or less or 100 °C or less, the lower limit being, for example, 90 °C or more, 95 °C or higher, 100 °C or higher, 105 °C or higher, 110 °C or higher or 115 °C or higher.

If the conditions of the extrusion step are not satisfied, since the foaming agent first foams before the polystyrene foam is extruded, open cells may be formed in the foam, and the surface quality of the molded article may be deteriorated.

In one example, the method further comprises a cooling step of cooling the mixture (e.g., a melt comprising at least a polystyrene resin and a methyl formate blowing agent according to the above-described process) after the step of introducing the blowing agent and before the step of extruding. could be a way to do it.

Although not particularly limited, the cooling may be performed in an extruder in which a foaming agent is introduced into the melt. Alternatively, cooling may be performed after the melt including the foaming agent is transferred from an extruder (eg, the first extruder) in which the foaming agent is introduced into the melt to another extruder (eg, the second extruder).

The cooling conditions may be determined by comprehensively considering equipment driving conditions and ease of foaming.

For example, the cooling may be performed at a temperature lower than the temperature at which the blowing agent is introduced, for example, 130 °C or lower, 120 °C or lower, or 110 °C or lower. If the above range is exceeded, foaming may proceed before extrusion, and open cells may occur.

In addition, the lower limit of the cooling temperature may be, for example, 100 ° C. or more. At temperatures lower than the above temperature range, problems such as equipment wear may occur.

In one example, the method may be a method of manufacturing lightweight polystyrene foam. The foam may have a density ranging from 25 to 35 kg/m ³ , for example. Specifically, the foam is 35 kg/m ³ or less, 34 kg/m ³ or less, 33 kg/m ³ or less, 32 kg/m ³ or less, 31 kg/m ³ or less, 30 kg/m ³ or less, 29 kg /m ³ or less, 28 kg/m ³ or less, 27 kg/m ³ or less, or 26 kg/m ³ or less, and 26 kg/m ^{3 or} more, 27 kg/m ³ or more, 28 kg/m ³ or more, 29 kg /m ³ or more, 30 kg/m ³ or more, 31 kg/m ³ or more, 32 kg/m ^{3 or} more, 33 kg/m ^{3 or} more, or 34 kg/m ³ or more. The foam of the present application may have a lower density than polystyrene foam showing a similar level of thermal conductivity (thermal insulation).

In another example related to the present application, the present application relates to a foaming composition for producing polystyrene foam. The composition may be used in relation to the above-described manufacturing method.

In one example, the composition may include 3.0 to 15.0 parts by weight of a methyl formate foaming agent based on 100 parts by weight of the polystyrene resin.

In one example, the composition may further include at least one selected from a flame retardant and a nucleating agent.

In one example, the composition may include 0.5 to 15 parts by weight of the flame retardant and 0.1 to 10 parts by weight of the nucleating agent based on 100 parts by weight of the polystyrene resin.

In one example, the composition further includes a heterogeneous foaming agent different from the methyl formate foaming agent, and the weight (W1) of the methyl formate foaming agent in the composition is the weight of the heterogeneous foaming agent (W2) may be more excessive. For example, in the composition, a ratio (W2/W1) of the weight (W2) of the heterogeneous foaming agent to the weight (W1) of the methyl formate foaming agent may be in the range of 0.015 to 0.4.

In addition, each component included in the composition, its content, and other characteristics are the same as those described above.

In another aspect of the present application, the present application relates to polystyrene foam. The polystyrene foam may be provided through the above-described manufacturing method.

In one example, the polystyrene foam may include 3.0 to 15.0 parts by weight of a methyl formate foaming agent based on 100 parts by weight of the polystyrene resin.

In one example, the polystyrene foam may further include at least one selected from a flame retardant and a nucleating agent.

In one example, the polystyrene foam may include 0.5 to 15 parts by weight of the flame retardant and 0.1 to 10 parts by weight of the nucleating agent based on 100 parts by weight of the polystyrene resin.

In one example, the polystyrene foam further includes a heterogeneous foaming agent different from the methyl formate foaming agent, and the weight (W1) of the methyl formate foaming agent in the composition is the heterogeneous foaming agent It may be more than the weight (W2). For example, in the polystyrene foam, a ratio (W2/W1) of the weight (W2) of the heterogeneous foaming agent to the weight (W1) of the methyl formate foaming agent may be in the range of 0.015 to 0.4.

In addition, each component included in the polystyrene foam, its content, and other characteristics are the same as those described above.

In one example, the foam may have a density ranging from 25 to 35 kg/m ³ . Specifically, the foam is 35 kg/m ³ or less, 34 kg/m ³ or less, 33 kg/m ³ or less, 32 kg/m ³ or less, 31 kg/m ³ or less, 30 kg/m ³ or less, 29 kg /m ³ or less, 28 kg/m ³ or less, 27 kg/m ³ or less, or 26 kg/m ³ or less, and 26 kg/m ^{3 or} more, 27 kg/m ³ or more, 28 kg/m ³ or more, 29 kg /m ³ or more, 30 kg/m ³ or more, 31 kg/m ³ or more, 32 kg/m ^{3 or} more, 33 kg/m ^{3 or} more, or 34 kg/m ³ or more. The foam of the present application may have a lower density than polystyrene foam showing a similar level of thermal conductivity (thermal insulation).

According to the present application using a methyl formate foaming agent, a conventional foaming agent known to destroy the ozone layer may not be used or the content thereof may be reduced, thereby providing an eco-friendly, lightweight, and excellent insulative polystyrene foam. In addition, the methyl formate blowing agent used in this application does not need to significantly change the existing process for reasons such as having a similar level of boiling point compared to conventional blowing agents, has a large foaming effect, and is inexpensive. The application has the effect of providing a polystyrene foam having excellent thermal conductivity without increasing costs or changing processes.

1 schematically illustrates a manufacturing process of polystyrene foam, according to an embodiment of the present application. Specifically, preparation of a melt containing a polystyrene resin (10), injection of a foaming agent into the melt (20), cooling of the mixture into which the foaming agent is added (30), and extrusion (or extrusion) (40) are sequentially performed. It can be.

Hereinafter, the action and effect of the invention will be described in more detail through specific examples of the invention. However, this is presented as an example of the invention, and thereby the scope of the invention is not limited in any sense.

Example 1

100 kg of polystyrene resin (product of LG Chem '25SPE'), 3.0 kg of hexabromocyclododecane (HBCD) as a flame retardant, and 1.0 kg of nucleating agent (TALC, D50 size of about 4 to 5 ㎛) were put into the primary extruder. and melted at about 250 °C.

And, in a state where a predetermined temperature (210 ° C.) and a predetermined pressure (1,600 psi) were formed in the primary extruder containing the melt containing the above components, a foaming agent was introduced. As the foaming agent, 0.8 kg of HFC-134a foaming agent and 7.0 kg of methyl formate, an eco-friendly foaming agent, were used.

Then, the temperature inside the primary extruder was cooled to about 120°C.

In addition, extruded polystyrene foam was prepared by extrusion and foaming under conditions of a temperature of 120 °C and a pressure of 950 psi .

Comparative Example 1

100 kg of polystyrene resin (product of LG Chem '25SPE'), 3.0 kg of hexabromocyclododecane (HBCD) as a flame retardant, and 1.0 kg of nucleating agent (TALC, D50 size of about 4 to 5 ㎛) were put into the primary extruder. and melted at about 250 °C.

And, in a state where the temperature (220 ° C.) and pressure (1,300 psi) different from those of Example 1 were formed, a foaming agent was introduced into the primary extruder containing the melt containing the above components. As the foaming agent, 0.8 kg of HFC-134a foaming agent and 2.0 kg of eco-friendly foaming agent (methyl formate) were used.

Thereafter, the temperature inside the primary extruder was cooled to about 120°C.

In addition, extruded polystyrene foam was prepared by extrusion and foaming under conditions different from those of Example 1 (temperature of 120 °C and pressure of 750 psi ).

The characteristics of the polystyrene foams of Example 1 and Comparative Example 1 prepared as described above are as follows.

division Example 1 Comparative Example 1 Density (kg/ℓ) 0.031 0.036 initial thermal conductivity
(W/mK) 0.024 to 0.026 0.028 to 0.030 surface Good Bad (Open Cell) Density (kg/ℓ): It can be converted into kg/m ³ units by multiplying x 1000.
Initial thermal conductivity: In accordance with Korean Industrial Standards KS L 9016, it was measured at an average temperature of 20 ± 5 ° C.

Comparing Example 1 and Comparative Example 1, it is confirmed that the styrene foam of Example 1, which satisfies the content of the foaming agent and the related process conditions, has excellent initial thermal conductivity (low value) compared to that of Comparative Example while having a low density. . For reference, the low initial thermal conductivity of Example 1 is a physical property corresponding to the special insulation material among the “A” grade insulation materials of the energy saving design standard for buildings (National Standard Certification Comprehensive Information Center (http://www.standard.go.kr)) reference).

Specifically, in Comparative Example 1 in which the process conditions for foam manufacturing did not satisfy the present application, open cells were generated, and as a result, the thermal conductivity value increased (heat insulating property decreased). In addition, in the case of Comparative Example 1, since the methyl formate is used in a small amount compared to Example 1, it is also confirmed that the density is increased (light weight is not good).

As a result, the present application provides a polystyrene foam that is environmentally friendly, lightweight, and has excellent heat insulating properties because a methyl formate foaming agent is used instead of a foaming agent known to destroy the ozone layer.

Claims (20)

A foaming agent input step of injecting a methyl formate foaming agent into a melt containing a polystyrene resin at a pressure of 1400 psi or more and a temperature of 215° C. or less; and
An extrusion step of extruding a mixture containing the melt and methyl formate;
Method for producing a polystyrene foam comprising a.
According to claim 1,
The blowing agent injection step is carried out by adding a methyl formate blowing agent to the melt at a pressure in the range of 1,450 psi to 1800 psi and a temperature in the range of 160 to 215 ° C.
Manufacturing method of polystyrene foam.
According to claim 1,
The extrusion step is performed by extruding a mixture containing the melt and methyl formate at a pressure of 800 psi or more and a temperature of 130 ° C or less,
Manufacturing method of polystyrene foam.
According to claim 3,
The extrusion step is performed by extruding a mixture comprising the melt and methyl formate at a pressure in the range of 850 to 1100 psi and a temperature in the range of 90 to 125 ° C.
Manufacturing method of polystyrene foam.
According to claim 1,
The melt containing the polystyrene resin further comprises at least one selected from a flame retardant and a nucleating agent.
Manufacturing method of polystyrene foam.
According to claim 5,
The melt contains 0.5 to 15 parts by weight of a flame retardant and 0.1 to 10 parts by weight of a nucleating agent, based on 100 parts by weight of the polystyrene resin.
Manufacturing method of polystyrene foam.
According to claim 1,
The step of adding the blowing agent is performed by adding 3.0 to 15.0 parts by weight of a methyl formate blowing agent relative to 100 parts by weight of the polystyrene resin.
Manufacturing method of polystyrene foam.
According to claim 7,
The step of introducing the blowing agent is performed by simultaneously or simultaneously introducing a different type of blowing agent from the methyl formate blowing agent,
The weight of the heterogeneous blowing agent is small compared to the methyl formate blowing agent,
Manufacturing method of polystyrene foam.
According to claim 8,
In the step of adding the foaming agent, the foaming agent is added so that the ratio (W2/W1) of the weight (W2) of the heterogeneous foaming agent to the weight (W1) of the methyl formate foaming agent is in the range of 0.015 to 0.4.
Manufacturing method of polystyrene foam.
According to claim 1,
A cooling step of cooling the mixture after the blowing agent input step and before the extrusion step; Including more,
Manufacturing method of polystyrene foam.
A foaming composition for producing polystyrene foam, comprising a polystyrene resin and a methyl formate foaming agent.
According to claim 11,
3.0 to 15.0 parts by weight of a methyl formate foaming agent based on 100 parts by weight of the polystyrene resin,
Foaming composition for producing polystyrene foam.
According to claim 11,
Further comprising at least one selected from flame retardants and nucleating agents,
Foaming composition for producing polystyrene foam.
According to claim 11,
Comprising 0.5 to 15 parts by weight of the flame retardant and 0.1 to 10 parts by weight of the nucleating agent, relative to 100 parts by weight of the polystyrene resin,
Foaming composition for producing polystyrene foam.
According to claim 11,
Further comprising a heterogeneous blowing agent different from the methyl formate blowing agent,
The ratio (W2/W1) of the weight (W2) of the heterogeneous foaming agent to the weight (W1) of the methyl formate foaming agent is in the range of 0.015 to 0.4,
Foaming composition for producing polystyrene foam.
A polystyrene foam comprising a polystyrene resin and a methyl formate blowing agent.
17. The method of claim 16,
Containing 1.0 to 15 parts by weight of a methyl formate foaming agent relative to 100 parts by weight of the polystyrene resin,
polystyrene foam.
17. The method of claim 16,
Further comprising at least one selected from flame retardants and nucleating agents,
polystyrene foam.
17. The method of claim 16,
Comprising 0.5 to 15 parts by weight of the flame retardant and 0.1 to 10 parts by weight of the nucleating agent, relative to 100 parts by weight of the polystyrene resin,
polystyrene foam.
17. The method of claim 16,
Further comprising a heterogeneous blowing agent different from the methyl formate blowing agent,
The ratio (W2/W1) of the weight (W2) of the heterogeneous foaming agent to the weight (W1) of the methyl formate foaming agent is in the range of 0.015 to 0.4,
polystyrene foam.

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