KR20240075299A - An extruded foam composition using hydrofluorocarbon, and an extruded foam using them - Google Patents

Abstract

One embodiment of the present specification includes a first polymer comprising a unit structure derived from an aromatic vinyl monomer and an unsaturated nitrile monomer; A second polymer comprising a unit structure derived from an aromatic vinyl monomer; Flame retardant masterbatch containing a cumene-based compound; It provides an extruded foam composition comprising; and hydrofluorocarbon.

Description

Extruded foam composition using hydrofluorocarbon and extruded foam using same {AN EXTRUDED FOAM COMPOSITION USING HYDROFLUOROCARBON, AND AN EXTRUDED FOAM USING THEM}

This specification relates to extruded foam compositions and extruded foams, and more specifically, to extruded foam compositions and extruded foams using hydrofluorocarbon as a blowing agent.

Among fluorine-based compounds, chloro fluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) have high latent heat of evaporation and critical temperature, and form a chemically stable structure, so they are used as first- and second-generation refrigerants. come. However, as chlorofluorocarbons, hydrochlorofluorocarbons, etc. were pointed out as the direct cause of ozone layer destruction, environmental regulations on chlorine-based refrigerants were strengthened, and while the use of chlorine-based refrigerants decreased, hydrofluorocarbons (HFCs) ), the use of fluorine-based refrigerants with an ozone depletion potential of 0 is increasing.

Hydrofluorocarbon has excellent physical properties not only as a refrigerant but also as a blowing agent. Hydrofluorocarbon has an average thermal conductivity of only 11.2 mW/m˙K measured at 10℃, which is close to the average thermal conductivity of 9.0 mW/m˙K of hydrochlorofluorocarbon, one of the commercially available refrigerants.

Therefore, foam manufactured using hydrofluorocarbon is attracting attention as a potential product that can replace existing foam. However, aromatic vinyl-based foam manufactured using hydrofluorocarbon has the disadvantage of very rapid change over time and relatively high density. This is because hydrofluorocarbons are polar while aromatic vinyl polymers are generally nonpolar, so the solubility of hydrofluorocarbons in aromatic vinyl polymers is low and their permeability is high.

To solve this problem, attempts were made to increase the solubility of hydrofluorocarbons by mixing various polymers with aromatic vinyl polymers.

For example, Japanese Patent Publication No. 2006-131757 discloses a foam obtained by blending polystyrene polymer with polyvinyl alcohol polymer and then foaming it using HFC-134a. However, since the solubility of HFC-134a in high molecular weight polymer is still low, there is a problem of poor combustibility of the foam even though HFC-134a, a non-flammable material, is used, and the density of the foam is high at 33 kg/m ³ , making it less economical. there is a problem.

As another example, Japanese Patent Publication No. 2006-131719 discloses a foam obtained by blending polystyrene polymer with acrylonitrile-alkylacrylate-butadiene copolymer and then foaming it using HFC-134a. However, since the density of the foam reaches 37 kg/m ³ , there is a problem of low economic feasibility.

As a means to solve the problems of the prior art described above, the present specification provides a foam with excellent thermal insulation properties using hydrofluorocarbon as a blowing agent.

In addition, it provides an economical foam with excellent physical properties while having a low change rate and density over time.

In addition, a method for improving the problem of deterioration in combustibility quality when blending an aromatic vinyl-based polymer and an unsaturated nitrile-based polymer is provided.

One aspect of the present specification is a first polymer comprising a unit structure derived from an aromatic vinyl monomer and an unsaturated nitrile monomer; A second polymer comprising a unit structure derived from an aromatic vinyl monomer; Flame retardant masterbatch containing a cumene-based compound; It provides an extruded foam composition comprising; and hydrofluorocarbon.

In one embodiment, the aromatic vinyl monomer is at least one selected from the group consisting of styrene, α-methylstyrene, vinyl toluene, t-butylstyrene, 1,3-dimethylstyrene, 2,4-dimethylstyrene, and ethylstyrene. You can.

In one embodiment, the unsaturated nitrile monomer may be at least one selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile, and α-chloroacrylonitrile.

In one embodiment, the content of the second polymer may be 10 to 90% by weight based on the weight of the matrix including the first polymer and the second polymer.

In one embodiment, the cumene-based compound is at least one selected from the group consisting of 1,4-diisopropylbenzene, poly-1,4-diisopropylbenzene, and 2,3-dimethyl-2,3-diphenylbutane. It could be one.

In one embodiment, the flame retardant masterbatch includes the cumene-based compound; A third polymer comprising a unit structure derived from an aromatic vinyl monomer; flame retardants; and a stabilizer;

In one embodiment, the content of the flame retardant masterbatch may be 1 to 5 parts by weight based on a total of 100 parts by weight of the first polymer and the second polymer.

In one embodiment, the hydrofluorocarbon is difluoromethane, 1,1,1,2,2-pentafluoroethane, 1,1,2,2-tetrafluoroethane, 1,1,1 ,2-tetrafluoroethane, 1,1-difluoroethane, 1,1,1,2,3,3,3-heptafluoropropane, 1,1,1,3,3,3-hexafluoro It may be at least one selected from the group consisting of propane, 1,1,1,3,3-pentafluoropropane, and 1,1,1,3,3-pentafluorobutane.

In one embodiment, the extruded foam composition further comprises at least one additive selected from the group consisting of a co-blowing agent, a nucleating agent, a pigment, and an infrared attenuating agent.

Another aspect of the present specification provides an extruded foam formed by foaming the above-described extruded foam composition, wherein the density measured according to KS M 3808 is 31.0 kg/m ³ or less.

The extruded foam according to one aspect of the present specification is environmentally friendly and can have excellent thermal insulation properties.

In addition, according to one aspect of the present specification, by blending a nitrile-based polymer with an aromatic vinyl-based polymer to increase the solubility of hydrofluorocarbon, it is possible to manufacture an economically feasible foam with excellent physical properties while lowering the change rate and density of the foam over time. .

In addition, according to one aspect of the present specification, the combustibility quality of the foam can be improved and quality deviation can be minimized by using a flame retardant masterbatch that interacts with an unsaturated nitrile-based polymer.

The effect of one aspect of the present specification is not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration described in the detailed description or claims of the present specification.

Hereinafter, various aspects of the present specification will be described. However, the description in this specification may be implemented in various different forms, and is not limited to the embodiments described herein.

Throughout the specification, when a part is said to be “connected” to another part, this includes not only cases where it is “directly connected,” but also cases where it is “indirectly connected” with another member in between. . Additionally, when a part is said to “include” a certain component, this does not mean that other components are excluded, but that other components can be added, unless specifically stated to the contrary.

As used herein, the term “ozone depletion potential (ODP)” refers to a value that quantifies the degree of ozone depletion of a specific compound based on the ozone depletion ability of trichlorofluorocarbon. At this time, the specific calculation method of the ozone depletion index is as described in the report of the World Meteorological Association's Global Ozone Research and Monitoring Project ("The Scientific Assessment of Ozone Depletion, 2002"). For example, the ozone depletion potential of chlorofluorocarbons is 0.6 to 1.0, that of halon compounds is very high at 3 to 10, and that of hydrochlorofluorocarbons is low at 0.001 to 0.52.

As used herein, the term “cell” refers to voids observed in conventional foams. At this time, the shape of the cell may include an open cell or a closed cell. If the average diameter of these cells is less than 10 ㎛, the density of the foam may excessively increase, and if it is more than 200 ㎛, the thermal insulation may be excessively reduced.

Unless otherwise stated, the weight percentages described in this specification are determined based on the matrix containing the first polymer and the second polymer.

As used herein, the term “matrix” refers to a component that constitutes a continuous phase in an extruded foam containing two or more components.

Extruded Foam Composition

An extruded foam composition according to one aspect of the present specification includes a first polymer including a unit structure derived from an aromatic vinyl monomer and an unsaturated nitrile monomer; A second polymer comprising a unit structure derived from an aromatic vinyl monomer; Flame retardant masterbatch containing a cumene-based compound; and hydrofluorocarbon.

The first polymer can be prepared by polymerizing a composition containing an aromatic vinyl monomer and an unsaturated nitrile monomer. The second polymer can be prepared by polymerizing a composition containing an aromatic vinyl monomer. As a result, the first polymer may include a unit structure of an aromatic vinyl monomer and an unsaturated nitrile monomer, and the second polymer may include a unit structure derived from an aromatic vinyl monomer.

The aromatic vinyl monomer of the first polymer or the second polymer is styrene, α-methyl styrene, vinyl toluene, t-butyl styrene, 1, respectively. , It may be at least one selected from the group consisting of 1,3-dimethyl styrene, 2,4-dimethyl styrene, and ethyl styrene, but is limited thereto. no.

The unsaturated nitrile monomer may be at least one selected from the group consisting of acrylonitrile, methacrylonitrile, phenyl acrylonitrile, and α-chloro acrylonitrile. However, it is not limited to this.

The content of the unsaturated nitrile monomer may be 1 to 33% by weight based on the weight of the first polymer. At this time, the content of the unsaturated nitrile monomer may be 1% by weight or more, 4% by weight or more, or 7% by weight or less, and 33% by weight or less, 30% by weight or less, or 27% by weight or less. If the content of the unsaturated nitrile monomer is less than 1% by weight, the solubility of the blowing agent in the first polymer may decrease, thereby reducing the thermal insulation properties of the foam. If the content of unsaturated nitrile monomer exceeds 33% by weight, the viscosity of the polymer may increase during the manufacturing process of the foam, which may reduce the processability and extrudability of the product, and the combustibility quality of the foam may deteriorate due to increased solubility of the combustible blowing agent. there is.

As a non-limiting example of the present specification, the first polymer may be a styrene-acrylonitrile copolymer in which the aromatic vinyl monomer is styrene and the unsaturated nitrile monomer is acrylonitrile. Additionally, the second polymer may be a styrene polymer in which the aromatic vinyl monomer is styrene. An example of such a styrene polymer is general purpose poly styrene (GPPS).

Hydrofluorocarbons have low solubility in aromatic vinyl polymers. Therefore, when hydrofluorocarbon is applied as a blowing agent in the conventional method of producing extruded aromatic vinyl polymer foam, there is a problem that the thermal insulation properties of the foam are deteriorated as the hydrofluorocarbon is easily dissipated during the foam manufacturing process.

In order to solve the above-mentioned problem, by blending an aromatic vinyl-based polymer with an unsaturated nitrile-based polymer with high hydrofluorocarbon solubility, the hydrofluorocarbon oxidation rate can be reduced to produce an extruded foam with excellent thermal insulation properties.

For example, acrylonitrile constituting the styrene-acrylonitrile copolymer has a polar functional group and therefore has excellent affinity with a polar blowing agent, such as HFC-134a. Therefore, as the content of styrene-acrylonitrile copolymer increases, the solubility of the polar blowing agent may increase. As the amount of blowing agent dissolved in the foam increases, the rate of change of the foam over time decreases and the foam density can be lowered. In addition, due to the inherent mechanical properties of the styrene-acrylonitrile copolymer, it is possible to produce an extruded foam with excellent compressive strength even if the content of the foaming agent is increased.

As an example, the weight average molecular weight of the first polymer may be 80,000 to 200,000 g/mol. At this time, the weight average molecular weight of the first polymer may be 80,000 g/mol or more, 90,000 g/mol or more, or 100,000 g/mol or more, and 200,000 g/mol or less, 170,000 g/mol or less, or 150,000 g/mol or less.

Meanwhile, the content of the second polymer may be 10 to 90% by weight based on the weight of the matrix including the first polymer and the second polymer. At this time, the content of the second polymer may be 10% by weight or more, 20% by weight or more, or 30% by weight or less, and 90% by weight or less, 80% by weight or less, or 70% by weight or less. If the content of the second polymer is less than 10% by weight, the compatibility of the first polymer and the second polymer decreases, making it difficult to control the thickness of the product, and patterns may appear on the surface of the product, increasing the defect rate of the product. . If the content of the second polymer exceeds 90% by weight, the solubility of the foaming agent in the high molecular weight polymer may decrease, thereby increasing the density and thermal conductivity of the foam.

The weight average molecular weight of the second polymer may be 150,000 to 300,000 g/mol. At this time, the weight average molecular weight of the second polymer may be 150,000 g/mol or more, 170,000 g/mol or more, or 210,000 g/mol or more, and 300,000 g/mol or less, 290,000 g/mol or less, or 280,000 g/mol or less.

On the other hand, blending unsaturated nitrile-based polymers may reduce the combustibility quality of the extruded foam. This is expected to be because unsaturated nitrile-based polymers deteriorate the performance of flame retardants. According to an example of the present specification, degradation of the performance of a flame retardant due to an unsaturated nitrile-based polymer can be suppressed by using a cumene-based compound.

The cumene-based compound may contain a cumene-based structure represented by the following chemical formula.

[Chemical formula]

In the above formula, R ₁ to R ₄ are each an alkyl group having 1 to 10 carbon atoms, and the dotted lines at both ends may be omitted. For example, if the compound represented by the above formula has one unit structure and R ₁ and R ₂ are methyl groups, it may be cumene.

As an example, the cumene-based compound may be at least one selected from the group consisting of 1,4-diisopropylbenzene, poly-1,4-diisopropylbenzene, and 2,3-dimethyl-2,3-diphenylbutane. However, it is not limited to this.

When a cumene-based compound is mixed with a flame retardant and used, the above-mentioned problem of unsaturated nitrile-based polymer deteriorating the performance of the flame retardant can be solved. However, if the cumene-based compound is added separately during extrusion of the foam, it may be difficult to improve the above-mentioned problems. Therefore, cumene-based compounds can be added in the form of a flame retardant masterbatch.

Here, the flame retardant masterbatch may include a cumene-based compound, a third polymer containing a unit structure derived from an aromatic vinyl-based monomer, a flame retardant, and a stabilizer. When a cumene-based compound is used in a masterbatch with a third polymer and a flame retardant, it is possible to manufacture an extruded foam with more uniform physical properties in addition to suppressing the performance degradation of the flame retardant due to the unsaturated nitrile-based polymer. Although the mechanism of action is not clearly known, it is expected that the third polymer, flame retardant, and cumene-based compound can be pre-mixed and dispersed to suppress performance degradation caused by the unsaturated nitrile-based polymer.

Here, the weight ratio of the cumene-based compound, the third polymer, the flame retardant, and the stabilizer may be 7.5 to 15:40 to 50:35 to 45:0.5 to 5, respectively. If the composition of the flame retardant masterbatch satisfies this range, the cumene-based compound, the third polymer, and the flame retardant interact to solve the problem of flame retardant performance degradation described above.

For example, based on 100% by weight of the flame retardant masterbatch, the content of cumene-based compounds is 7.5% by weight, 8% by weight, 8.5% by weight, 9% by weight, 9.5% by weight, 10% by weight, 10.5% by weight, and 11% by weight. , 11.5% by weight, 12% by weight, 12.5% by weight, 13% by weight, 13.5% by weight, 14% by weight, 14.5% by weight, 15% by weight, or a range between these two values.

The content of the third polymer is 40% by weight, 41% by weight, 42% by weight, 43% by weight, 44% by weight, 45% by weight, 46% by weight, 47% by weight, 48% by weight, 49% by weight, 50% by weight, or It can be a range between two of these values.

The content of the flame retardant is 35% by weight, 36% by weight, 37% by weight, 38% by weight, 39% by weight, 40% by weight, 41% by weight, 42% by weight, 43% by weight, 44% by weight, 45% by weight, or any of these. It can be a range between two values.

The content of the stabilizer is 0.5% by weight, 1% by weight, 1.5% by weight, 2% by weight, 2.5% by weight, 3% by weight, 3.5% by weight, 4% by weight, 4.5% by weight, 5% by weight, or between the two values. It may be a range.

The third polymer contains a unit structure derived from the aromatic vinyl monomer described above and may be the same as the first polymer, the same as the second polymer, or different from both the first polymer and the second polymer, but is not limited thereto. no.

The flame retardant may be at least one selected from the group consisting of brominated flame retardants, phosphorus-based flame retardants, and inorganic flame retardants. Examples of commonly used brominated flame retardants include hexabromo cyclododecane and tetrabromo bisphenol A-bis(2,3-dibromopropyl) ether. -dibromo propyl ether), tris(2,3-dibromopropyl) isocyanurate, brominated styrene-butadiene-styrene copolymer, Br- SBS), etc. These flame retardants can be added within the range that does not adversely affect the insulation properties of the foam.

Stabilizers commonly used in flame retardant compositions in the art can be used. For example, it may be at least one selected from the group consisting of epoxy compounds, phenol-based stabilizers, phosphite-based stabilizers, alcohol-based stabilizers, ester-based stabilizers, and hindered amine-based stabilizers. Depending on the type of flame retardant, a suitable stabilizer can be selected and used.

As a non-limiting example of the present specification, the flame retardant masterbatch may further include a phosphorus-based flame retardant as a flame retardant auxiliary. Examples of phosphorus-based flame retardants include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, and trimethyl phosphate. (trimethyl phosphate), triethyl phosphate, tris(2-ethylhexyl) phosphate, tris(butoxyethyl) phosphate, etc. These flame retardant adjuvants can be added within the range that does not adversely affect the thermal insulation properties of the foam.

The content of the flame retardant masterbatch is 1 to 5 parts by weight, for example, 1 part by weight, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, based on 100 parts by weight of the total of the first polymer and the second polymer. It may be parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight, or a range between these two values. If the content of the flame retardant masterbatch is outside the above-mentioned range, the combustibility quality of the extruded foam may deteriorate, the appearance quality may deteriorate, or the mechanical properties may be insufficient.

Extruded foams manufactured by applying only hydrofluorocarbons to conventional products have a problem in that they do not meet the density and other physical properties required by the industry. Accordingly, by adding an aromatic vinyl polymer or using carbon dioxide, ethanol, water, etc. as a co-blowing agent, a foam with a slow change rate over time and balanced physical properties can be manufactured.

Hydrofluorocarbons have high solubility and low permeability in blends of aromatic vinyl-based polymers and unsaturated nitrile-based copolymers. Therefore, applying hydrofluorocarbon to these blends slows down the rate of acidification, making it possible to produce extruded foams with a low rate of change in thermal conductivity and low density.

The hydrofluorocarbon is difluoromethane (difluoro methane, HFC-32), 1,1,1,2,2-pentafluoroethane (1,1,1,2,2-pentafluoro ethane, HFC-125) ), 1,1,2,2-tetrafluoroethane (1,1,2,2-tetrafluoro ethane, HFC-134), 1,1,1,2-tetrafluoroethane (1,1,1, 2-tetrafluoro ethane, HFC-134a), 1,1-difluoro ethane (1,1-difluoro ethane, HFC-152a), 1,1,1,2,3,3,3-heptafluoropropane ( 1,1,1,2,3,3,3-heptafluoro propane, HFC-227ea), 1,1,1,3,3,3-hexafluoropropane (1,1,1,3,3,3 -hexafluoro propane, HFC-236fa), 1,1,1,3,3-pentafluoropropane (1,1,1,3,3-pentafluoro propane, HFC-245fa) and 1,1,1,3, It may be at least one selected from the group consisting of 3-pentafluorobutane (1,1,1,3,3-pentafluoro butane, HFC-365mfc). These hydrofluorocarbons may be used individually or two or more types may be used in combination.

According to the majority of previous research results, HFC-32, HFC-134a, and HFC-152a have lower permeability to aromatic vinyl polymers compared to other blowing agents, but have proportionally low solubility. Therefore, if the solubility of HFC-32, HFC-134a, and HFC-152a in the high molecular weight polymer can be increased, the thermal conductivity of the foam can be significantly lowered by slowing down the dissolution rate of the blowing agent. For example, blending an aromatic vinyl polymer with an unsaturated nitrile copolymer with excellent solubility of HFC-32, HFC-134a, and HFC-152a not only increases the solubility of the blowing agent in the polymer, but also significantly improves the thermal conductivity of the foam. By reducing it, problems caused by the rate of change of the foam over time can be improved.

The content of hydrofluorocarbon may be 1 to 50 parts by weight based on a total of 100 parts by weight of the first polymer and the second polymer. At this time, the content of hydrofluorocarbon is 1 part by weight, 3 parts by weight, or 5 parts by weight, and 50 parts by weight or less, 30 parts by weight, or 10 parts by weight, based on 100 parts by weight of the total of the first polymer and the second polymer. It may be less than 100%. If the hydrofluorocarbon content is less than 1 part by weight, the amount of gas remaining inside the foam is small, so the insulation properties of the foam may be reduced. If the hydrofluorocarbon content exceeds 50 parts by weight, the amount of foaming agent that is not dissolved in the high molecular weight polymer may increase, resulting in numerous pores occurring on the surface of the product and an increase in the defect rate of the product.

Meanwhile, the extruded foam composition may further include at least one additive selected from the group consisting of a co-foaming agent, a nucleating agent, a pigment, and an infrared attenuator.

Here, the co-blowing agent may be at least one selected from the group consisting of carbon dioxide, methanol, ethanol, isopropanol, and water. As an example, it may be a combination of carbon dioxide, ethanol, and water, but is not limited to this.

As a non-limiting example of the present specification, carbon dioxide may be included as a co-blowing agent. Carbon dioxide can improve the compressive strength of foam by reducing cell size. In addition, since it is cheaper than other foaming agents, the manufacturing cost of foam can be reduced. However, if added in excessive amounts, the density of the foam may increase due to a decrease in cell size, which may reduce the economic feasibility of the foam. Therefore, the content of carbon dioxide may be 0.1 parts by weight or more, 0.2 parts by weight or more, or 0.3 parts by weight or less, and 5 parts by weight or less, 4 parts by weight or less, or 3 parts by weight or less, based on a total of 100 parts by weight of the first polymer and the second polymer. . If the carbon dioxide content is less than 0.1 parts by weight, the amount of gas remaining inside the foam is small, so the insulation properties of the foam may be reduced. If the carbon dioxide content exceeds 5 parts by weight, the foaming agent that is not dissolved in the high molecular weight polymer may increase, resulting in numerous pores on the product surface and an increase in the defect rate of the product.

As a non-limiting example of the present specification, ethanol may be included as a co-blowing agent. At this time, the content of ethanol is 0.1 parts by weight or more, 0.2 parts by weight or more, or 0.3 parts by weight or more, and may be 6 parts by weight or less, 5 parts by weight or less, or 4 parts by weight or less, based on 100 parts by weight of the total of the first polymer and the second polymer. there is. If the ethanol content is less than 0.1 parts by weight, the amount of gas remaining inside the foam is small, so the insulation properties of the foam may be reduced. If the ethanol content exceeds 6 parts by weight, the foaming agent that is not dissolved in the high molecular weight polymer may increase, resulting in numerous pores on the product surface and an increase in the defect rate of the product.

As a non-limiting example of the present specification, water may be included as a co-foaming agent. At this time, the water content is 0.1 parts by weight or more, 0.3 parts by weight or more, or 0.5 parts by weight or less, and may be 3 parts by weight or less, 2.8 parts by weight or less, or 2.6 parts by weight or less, based on a total of 100 parts by weight of the first polymer and the second polymer. . Water can reduce the density of the foam by increasing the cell size, thereby improving the economics of the foam. In addition, since it is cheaper than other foaming agents, the manufacturing cost of foam can be reduced. If the water content is less than 0.1 parts by weight, the amount of gas remaining inside the foam is small, so the insulation properties of the foam may be reduced. If the water content exceeds 3 parts by weight, an open cell structure may be formed, which may reduce the thermal insulation and compressive strength of the foam.

These foaming agents or co-foaming agents may be used alone or two or more types may be used in combination. At this time, the content of the blowing agent and co-blowing agent may not exceed 10 parts by weight based on a total of 100 parts by weight of the first polymer and the second polymer. If the content of the foaming agent and co-blowing agent exceeds 10 parts by weight, the viscosity of the polymer may increase and the processability and extrudability of the product may decrease.

As a non-limiting example of the present specification, the nucleating agent may be one of talc, calcium carbonate, and silica, and preferably, talc.

As a non-limiting example of the present specification, the pigment includes titanium dioxide, zinc oxide, ferrous oxide, antimony oxide, and chromium(III) oxide. , lead(II) chromate, and preferably titanium dioxide.

As a non-limiting example of the present specification, the infrared attenuator may be one of graphite, titanium oxide, zinc oxide, aluminum oxide, and antimony oxide. and, preferably, it may be graphite. Here, the infrared attenuator refers to a material that allows the foam to absorb light in the infrared or near-infrared region by reflecting or scattering light in the infrared or near-infrared region.

These co-foaming agents, nucleating agents, pigments, and infrared attenuators may be used alone or two or more types may be used in combination.

Extruded foam and its manufacturing method

The extruded foam formed by foaming the above-described extruded foam composition may have a density of 31.0 kg/m ³ or less as measured according to KS M 3808. At this time, the density of the foam may be 31.0 kg/m ³ or less, 30.0 kg/m ³ or less, or 29.0 kg/m ³ or less.

In another example, the foam may have a combustion length measured according to KS M 3808 of 60 mm or less while satisfying the density described above.

The method for producing such extruded foam includes (a) preparing a flame retardant masterbatch containing a cumene-based compound; (b) heating the extruder to 180-240°C to melt and knead the extruded foam composition including the first polymer, the second polymer, the flame retardant masterbatch, and the hydrofluorocarbon; (c) cooling the product of step (b) at 100-140°C; and (d) extruding and foaming the product of step (c) at 3 to 10 MPa.

As a non-limiting example of the present specification, melt kneading in step (b) may be performed at a temperature of 180 to 240°C. At this time, the temperature condition may be 180°C or higher or 190°C or higher and 240°C or lower or 230°C or lower. If the temperature is less than 180°C, the miscibility of the first polymer and the second polymer may decrease and the extrudability and processability of the foam may decrease. If the temperature exceeds 240°C, the solubility of the foaming agent in the high molecular weight polymer may decrease, thereby increasing the density and thermal conductivity of the foam.

As a non-limiting example of the present specification, cooling in step (c) may be performed at a temperature of 100 to 140°C. In general, as the cooling temperature increases, the density of the foam may decrease. At this time, the temperature condition may be 100℃ or higher or 110℃ or lower and 140℃ or lower or 130℃ or lower. If the temperature is less than 100°C, the uniformity of cells formed inside the foam may decrease due to rapid cooling, and as the density of the foam increases, economic efficiency may decrease. If the temperature exceeds 140°C, multiple pores may occur on the product surface due to an increase in the rate of foaming agent production.

In step (b), at least one additive selected from the group consisting of flame retardants, flame retardant aids, nucleating agents, pigments, and infrared attenuators may be further included and melt-kneaded.

As a non-limiting example of the present specification, in step (d), the foam may be foamed at a pressure of 3 to 10 MPa. In general, as the foaming pressure increases, the density of the foam increases and a beautiful product appearance can be achieved. At this time, the pressure condition may be 3 MPa or more or 4 MPa or more and 10 MPa or less or 8 MPa or less. If the pressure is less than 3 MPa, the rate of dispersion of the foaming agent increases rapidly, which can cause numerous pores to appear on the product surface and increase the defect rate of the product. If the pressure exceeds 10 MPa, economic feasibility may decrease as the density of the foam increases, and the load on the extruder may rapidly increase, causing a significant decrease in extrusion speed.

After step (d), the method may further include molding the product of step (d). The molded form of the product in step (d) is architectural interior material, flooring material, ceiling material, soundproofing material for civil construction, sound insulating material for civil construction, sound absorbing material for civil construction, thermal insulation material for civil construction, thermal insulation coating material for heat pipe, dustproof material for civil construction, and protective covering material for civil construction. , cushioning materials, cushioning packaging materials for electrical and electronic components, protective coating materials, furniture boards, decorative sheets, interior materials for transportation vehicles, fire protection clothing, and clothing fibers; It can be one of felt, non-woven fabric, clothing, stationery, and toys.

Hereinafter, embodiments of the present specification will be described in detail.

Manufacturing examples and comparative manufacturing examples

Polystyrene (PS) polymer as the resin, brominated styrene-butadiene-styrene resin as the flame retardant, 2,3-dimethyl-2,3-diphenylbutane as the flame retardant auxiliary 1, and poly-1,4-diisopropylbenzene as the flame retardant auxiliary 2. A flame retardant masterbatch was prepared by mixing and pelletizing the stabilizer according to the composition in Table 1 below.

division PS resin flame retardant Flame retardant supplement 1 Flame retardant supplement 2 stabilizator Comparative manufacturing example 47 46 5 0 2 Manufacturing Example 1 47 38 13 0 2 Production example 2 47 38 6.5 6.5 2

(Unit: weight%)

Comparative Examples 1 to 4

Polystyrene polymer, HFC-134a, HFC-32, carbon dioxide, and water were prepared as shown in Table 1 below.

Polystyrene polymer was melt-kneaded at 200-220°C in a twin-screw extruder. Afterwards, HFC-134a, HFC-32, carbon dioxide, and water were pressurized into the extruder with a pump, cooled at 120°C, and extruded and foamed at a pressure of 8 MPa, thereby obtaining a foam.

Examples 1 to 4

Polystyrene polymer, styrene-acrylonitrile (SAN) copolymer, flame retardant masterbatch of Comparative Preparation Examples and Preparation Examples, HFC-134a, HFC-32, carbon dioxide, and water were prepared as shown in Table 1 below. Here, the content of acrylonitrile is 20% by weight based on the weight of the styrene-acrylonitrile copolymer. In addition, 2.5% by weight of the flame retardant masterbatch was added based on the total of polystyrene polymer and styrene-acrylonitrile copolymer.

Polystyrene polymer and styrene-acrylonitrile copolymer were added to a twin screw extruder, and melt-kneaded at 200-220°C. Afterwards, HFC-134a, HFC-32, carbon dioxide, ethanol, and water were pressurized into the extruder with a pump, cooled at 120°C, and extruded and foamed at a pressure of 8 MPa, thereby obtaining a foam.

item Comparative example Example One 2 3 4 One 2 3 4 PS polymer
(weight%) 100 80 100 100 80 70 80 70 SAN copolymer (% by weight) 0 20 0 0 20 30 20 30 Flame retardant masterbatch Comparative manufacturing example Comparative manufacturing example Manufacturing Example 1 Production example 2 Manufacturing Example 1 Manufacturing Example 1 Production example 2 Production example 2 HFC-134a (parts by weight) 4 3.5 4 4 3.5 3.5 3.5 3.5 HFC-152a (parts by weight) - 5.5 - - 5.5 5.5 5.5 5.5 HFC-32 (by weight) 4 - 4 4 - - - - Carbon dioxide (parts by weight) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Water (parts by weight) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5

Comparative Example 5

A foam was prepared in the same manner as in Example 1, except that instead of the flame retardant masterbatch of Preparation Example 1, the components contained therein were added in powder or pellet form.

Experimental Example 1

In order to confirm the effect of introducing the styrene-acrylonitrile copolymer and each flame retardant masterbatch, the physical properties of the foams prepared according to Comparative Examples 1 to 4 and Examples 1 to 4 were measured. At this time, the physical properties of the foam were measured according to the Korean Industrial Standard KS M 3808. Table 3 below shows the results of evaluating the density, combustion length, and product appearance of the foam.

item Comparative example Example One 2 3 4 One 2 3 4 density
(kg/ ^m3 ) 32.0 29.5 32.2 31.5 29.5 29.0 29.4 29.2 combustion length
(mm) 50 65 49 49 58 60 57 58 Product appearance ○ ○ ○ ○ ○ ○ ○ ○

Referring to Comparative Example 1 and Comparative Example 2, it can be seen that the density can be reduced by introducing styrene-acrylonitrile copolymer as the resin of the foam.

Through this, it can be seen that as the styrene-acrylonitrile copolymer is introduced, the solubility of hydrofluorocarbon in the polymer increases, the amount of foaming agent remaining inside the foam after extrusion increases, and the density of the foam decreases accordingly. You can. Also, based on this, it is predicted that the thermal conductivity of the foam and its rate of change over time will decrease.

The foam of Comparative Example 2 has a problem in that its combustibility quality is lowered compared to Comparative Example 1 as the styrene-acrylonitrile copolymer is mixed and used. On the other hand, the foams of Examples 1 to 4 using the flame retardant masterbatch of Preparation Example 1 and Preparation Example 2 had low density and excellent combustibility quality.

Comparative Examples 3 and 4, in which the flame retardant masterbatch of Preparation Example 1 and Preparation Example 2 were applied to polystyrene polymer, were similar in combustibility quality, density, etc. to Comparative Example 1 in which the flame retardant masterbatch of Comparative Preparation Example was applied. Comparing this with Examples 1 to 4, it can be confirmed that the flame retardant masterbatch of Preparation Example 1 and Preparation Example 2 and the styrene-acrylonitrile copolymer have a synergistic interaction.

Experimental Example 2

The combustibility quality of the foams of Example 1 and Comparative Example 5 containing the same ingredients were measured and shown in Table 4 below.

division 1st round 2nd round 3rd session 4th session 5th session average Standard Deviation Example 1 53 52 48 49 47 50 2.32 Comparative Example 5 60 49 55 58 52 55 3.97

(Unit: mm)

Referring to Table 4 above, it can be seen that the foam of Example 1 has excellent combustibility quality compared to Comparative Example 5, and the quality deviation is also small. Based on this, it can be predicted that the variation in other physical properties of the foam will also decrease.

The description of the present specification described above is for illustrative purposes, and those skilled in the art can easily transform the details of this specification into other specific forms without changing the technical idea or essential features of the specification. You will be able to understand that Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. For example, each component described as single may be implemented in a distributed manner, and similarly, components described as distributed may also be implemented in a combined form.

The scope of the matters described in this specification is indicated by the claims described below, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the matters described in this specification.

Claims (10)

A first polymer comprising a unit structure derived from an aromatic vinyl monomer and an unsaturated nitrile monomer;
A second polymer comprising a unit structure derived from an aromatic vinyl monomer;
Flame retardant masterbatch containing a cumene-based compound; and
Extruded foam composition comprising a hydrofluorocarbon. According to paragraph 1,
The extruded foam composition wherein the aromatic vinyl monomer is at least one selected from the group consisting of styrene, α-methylstyrene, vinyl toluene, t-butylstyrene, 1,3-dimethylstyrene, 2,4-dimethylstyrene, and ethylstyrene. According to paragraph 1,
The extruded foam composition, wherein the unsaturated nitrile monomer is at least one selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile, and α-chloroacrylonitrile. According to paragraph 1,
The extruded foam composition wherein the content of the second polymer is 10 to 90% by weight based on the weight of the matrix comprising the first polymer and the second polymer. According to paragraph 1,
The extruded foam composition wherein the cumene-based compound is at least one selected from the group consisting of 1,4-diisopropylbenzene, poly-1,4-diisopropylbenzene, and 2,3-dimethyl-2,3-diphenylbutane. . According to paragraph 1,
The flame retardant masterbatch is,
The cumene-based compound;
A third polymer comprising a unit structure derived from an aromatic vinyl monomer;
flame retardants; and
An extruded foam composition comprising a stabilizer. According to paragraph 1,
The extruded foam composition wherein the content of the flame retardant masterbatch is 1 to 5 parts by weight based on 100 parts by weight of the total of the first polymer and the second polymer. According to paragraph 1,
The hydrofluorocarbon is difluoromethane, 1,1,1,2,2-pentafluoroethane, 1,1,2,2-tetrafluoroethane, 1,1,1,2-tetrafluoro Ethane, 1,1-difluoroethane, 1,1,1,2,3,3,3-heptafluoropropane, 1,1,1,3,3,3-hexafluoropropane, 1,1 An extruded foam composition, which is at least one selected from the group consisting of 1,3,3-pentafluoropropane and 1,1,1,3,3-pentafluorobutane. According to paragraph 1,
An extruded foam composition further comprising at least one additive selected from the group consisting of a co-blowing agent, a nucleating agent, a pigment, and an infrared attenuator. In the extruded foam formed by foaming the extruded foam composition according to any one of claims 1 to 9,
Extruded foam with a density measured in accordance with KS M 3808 of 31.0 kg/m ³ or less.