Carboxamide reduction additive for blowing agent and blowing agent composition including same

Abstract

The present invention provides a formamide reducing additive for a foaming agent and a foaming agent composition using the same, which can significantly reduce the concentration of formamide generated during ADCA foaming and reduce the concentration of formamide remaining in a finished foam.

Description

Technical Field

[0001] The present invention relates to a formamide reducing additive for a foaming agent, in particular to an additive capable of reducing the concentration of formamide generated in foaming agents such as ADCA and the concentration of residual formamide in a finished foam, and a foaming agent composition comprising the additive. Background Art

[0002] A foaming agent is a synthetic resin additive that is mixed with synthetic resin to produce porous foams. It is a substance used to provide the gas required for foaming during foam molding.

[0003] Among the above-mentioned foaming agents, azodicarbonamide (hereinafter referred to as ADCA) is an additive used in various plastics such as EVA, PE, PVC, and PP. It is a chemical foaming agent that occupies a major share of the foaming agent market due to its many advantages such as high foaming ratio, low cost, and effective decomposition temperature control.

[0004] However, the commonly used ADCA will generate a large amount of formamide together with N2 gas when it undergoes thermal decomposition during the foaming process, causing problems for the working environment. After commercialization, the release of formamide may cause environmental problems.

[0005] In order to remove formamide produced by ADCA, attempts have been made to remove it physically using adsorbents, chemically removing it, or introducing acidic substances through acid-base reactions.

[0006] However, because ADCA foams at high temperatures of 200°C to 230°C, the adsorbents used in ADCA are subject to a phenomenon in which formamide is adsorbed and then desorbed at high temperatures. Furthermore, the formamide concentration reduction of existing adsorbents fluctuates depending on the foaming conditions, making them extremely unstable and resulting in poor performance. Furthermore, the use of acids or bases can cause foam defects.

[0007] Related Korean Patent No. 10-1915690 discloses a method for capturing and reducing harmful substances produced when azo foaming compounds are thermally decomposed using porous metal oxides. However, even though this method has a certain effect in reducing formamide, it can also cause side effects in the foamed foam and changes in the foaming properties.

[0008] In addition, Korean Patent Publication No. 2005-0101689, Korean Patent Publication No. 2017-0103764, and Korean Patent Publication No. 2005-0069178 disclose methods for removing toxic gases by impregnating a metal into a porous material. However, these methods are intended to remove toxic gases such as combustion exhaust gas or carbon monoxide, and do not recognize methods for removing formamide, a harmful substance, from ADCA. Summary of the Invention

[0009] Problems to be solved by the invention

[0010] An object of the present invention is to provide a formamide-reducing additive for a blowing agent, which can more effectively reduce formamide from a blowing agent by impregnating a porous material such as zeolite with at least one metal including Cu metal.

[0011] In addition, the present specification also aims to provide a foaming composition that utilizes the formamide-reducing additive for a foaming agent to effectively reduce the formamide concentration in a foam, and a foam formed by foaming the composition.

[0012] Means used to solve problems

[0013] In the present specification, a formamide-reducing additive for a blowing agent is provided, which includes: a porous zeolite including a plurality of pores; and a metal including a first metal contained and impregnated in part or all of the pores.

[0014] In addition, according to another embodiment of the present specification, a blowing agent composition is provided, which includes a blowing agent and the above-mentioned formamide-reducing additive.

[0015] In addition, according to the present specification, a foaming composition is also provided, which includes the above-mentioned foaming agent composition and a foaming target resin, wherein the foaming target resin includes at least one selected from the group consisting of polyethylene, polypropylene, polyvinyl chloride, polycarbonate, polystyrene, polyamide, polyoxymethylene, styrene-butadiene rubber, ethylene-vinyl acetate copolymer (EVA), ethylene-propylene rubber, thermoplastic elastomer, thermoplastic polyurethane, thermoplastic rubber, ABS resin, rubber, epoxy resin and acrylic resin.

[0016] Hereinafter, embodiments of the present invention will be described in more detail. The terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings, but should be understood as meanings and concepts consistent with the technical concept of the present invention, based on the principle that the inventor can appropriately define the concept of the term in order to best describe his invention.

[0017] In addition, the word "comprising" used in this specification is intended to specify certain characteristics, regions, integers, steps, actions, elements and / or components, and does not exclude the existence or addition of other characteristics, regions, integers, steps, actions, elements and / or components.

[0018] The "formamide-reducing additive for a foaming agent" in this specification refers to an additive that can remove residual formamide in a foam and reduce its concentration.

[0019] The residual formamide concentration herein refers to a concentration measured on a blowing agent composition comprising a blowing agent and the formamide-reducing additive for the blowing agent without being mixed with a resin to be foamed.

[0020] The residual formamide concentration in the foaming resin (ie, the residual formamide concentration in the foam) refers to the concentration measured after mixing the foaming target resin with the above-mentioned blowing agent composition.

[0021] Hereinafter, a formamide-reducing additive for a blowing agent, a blowing agent composition using the same, and a foamed article according to one embodiment of the present invention will be described in more detail.

[0022] According to one embodiment of the present invention, a formamide-reducing additive for a blowing agent may be provided, comprising: a porous zeolite including a plurality of pores; and a metal including a first metal contained and impregnated in part or all of the pores.

[0023] The metal includes metal ions, and may be impregnated in part or all of the pores of the porous zeolite in the form of metal ions.

[0024] The present inventors have developed a formamide-reducing additive comprising at least one metal, including Cu metal, impregnated (supported) in a porous material such as zeolite, and have demonstrated that the additive, when applied to a blowing agent and a finished foam, can significantly reduce not only the formamide concentration in the blowing agent but also the residual formamide concentration in the foam, thereby completing the present invention.

[0025] Therefore, the present specification is characterized in that a formamide-reducing additive for a blowing agent is provided, which can effectively remove formamide, a specific harmful substance generated during the foaming process of the blowing agent (e.g., ADCA) and remaining in the foam, and reduce its concentration, and has a carrier form in which at least one metal is impregnated (supported) in the form of ions in part or all of the multiple pores of a porous zeolite.

[0026] The above-mentioned foaming agent produces N2, carbon monoxide and ammonia during the thermal decomposition process due to foaming. When the above-mentioned formamide-reducing additive is added, carbon monoxide can be oxidized into carbon dioxide, and the porous zeolite captures moisture, thereby suppressing the generation of formamide without causing side effects of the foaming agent and the foam.

[0027] Furthermore, the formamide reducing additive is a non-catalytic additive specifically used to remove and reduce formamide in the blowing agent and the foam containing the blowing agent.

[0028] The formamide-reducing additive described above may comprise a Group 11 metal as the first metal.

[0029] Furthermore, the formamide-reducing additive may further comprise at least one second metal in addition to the first metal. When both the first and second metals are present, the second metal can reduce activation energy, thereby providing additional synergistic effects such as temperature regulation and increased expansion ratio when reducing formamide concentration.

[0030] That is, the formamide-reducing additive is applied to the foaming agent by impregnating a porous zeolite containing multiple pores with two or more metals (e.g., CuMnA). Compared with the existing method of applying metal oxides, it not only has fewer side effects on the finished foam, but also can more effectively reduce formamide.

[0031] Specifically, the first metal may include at least one metal selected from the group consisting of metals in Group 11. The first metal may be in the form of first metal ions, and may be impregnated in part or all of the pores of the porous zeolite in the form of first metal ions.

[0032] More specifically, the first metal may be at least one selected from the group consisting of Cu and Ag. For example, the first metal may include Cu. When the first metal necessarily includes Cu, the metal can be effectively impregnated into the pores of the porous zeolite, thereby exhibiting high performance in reducing formamide generated during the ADCA foaming process.

[0033] In addition, the metal may further include a second metal different from the first metal. Similar to the first metal, the second metal may be in the form of a second metal ion and may be impregnated in part or all of the pores of the porous zeolite in the form of the second metal ion along with the first metal ion.

[0034] The second metal may be at least one selected from the group consisting of metals from Groups 1, 3 to 10, 12, and 13. More specifically, the second metal may include at least one selected from the group consisting of Mn, Si, Cr, Ce, Cs, Fe, Co, Zn, Ni, Zr, and Al.

[0035] In addition, in the present specification, by adjusting the weight ratio of at least one metal impregnated in the porous material, the reduction rate of formamide can be effectively increased without any side effects.

[0036] The weight ratio of the first metal to the second metal may be 1:9 to 17:0 relative to the total content of the metal ions.

[0037] According to a preferred embodiment, the weight ratio of the first metal to the second metal relative to the total content of the metals may be 1:9 to 16.9:0.1. In other words, when the metal further includes a second metal, the weight ratio of the first metal to the second metal relative to the total content of the metals may be 1:0.006 to 1:9.

[0038] While increasing the first metal content improves the formamide reduction rate, it can also hinder crosslinking reactions, leading to foam damage or a significant reduction in gas production. Furthermore, when the first metal content is too low, the formamide removal effect is minimal. Therefore, the first and second metals should be used within the above ranges to effectively reduce the formamide concentration in the blowing agent and foam without adverse effects.

[0039] In addition, the reduction rate of formamide and the side effects of the foam can be adjusted according to the situation. For example, the weight ratio of the first metal to the second metal can be adjusted to 1:0.05-1:0.1, 1:0.5-1:1, 1:2-1:3, 1:4-1:9, 2:1-9:1.

[0040] In one embodiment, the weight ratio of the first metal to the second metal may be 1:1. When manufacturing the formamide-reducing additive, when the first metal and the second metal are impregnated into the porous material zeolite at a ratio of 1:1, the lowest side effects and the highest formamide reduction rate can be achieved.

[0041] In addition, the formamide-reducing additive for a blowing agent may include: 83 wt % to 99 wt % of the porous zeolite; and 1 wt % to 17 wt % of the metal ion.

[0042] If the metal ion content is less than 1% by weight, the amount of metal ions impregnated into the porous zeolite is too low, resulting in minimal formamide removal from the blowing agent. Furthermore, if the metal ion content exceeds 17% by weight, the metal ions are not impregnated into the zeolite but remain in the solution used to prepare the formamide-reducing additive, ultimately being discarded as wastewater.

[0043] The average particle size of the porous zeolite may be 1 μm to 20 μm, or 2 μm to 5 μm. In addition, the pore size of the porous zeolite measured by BET analysis may be to

[0044] The porous zeolite can be purchased as a product such as 4A zeolite.

[0045] The above-mentioned formamide-reducing additive for a blowing agent can be prepared into a granular form by mixing an aqueous solution of a metal sulfur compound with porous zeolite.

[0046] Specifically, when preparing the above-mentioned formamide-reducing additive, the material used to impregnate the metal in the zeolite in the form of ions can be selected from metal-containing nitric acid aqueous solutions and sulfur compound aqueous solutions, but from the perspectives of stability, handling convenience and economy, it is preferred to use metal sulfide aqueous solutions.

[0047] Specifically, metal-containing aqueous nitric acid solutions contain substances that are considered hazardous, making them difficult to store and potentially problematic during large-scale production. In contrast, aqueous solutions prepared using metal sulfide compounds are more affordable than metal-containing aqueous nitric acid solutions and contain no hazardous or harmful substances, making them more suitable for practical applications.

[0048] The formamide-reducing additive can be prepared by adding a porous material to a metal-containing sulfur compound aqueous solution and stirring the solution to form at least one metal supported by ions impregnated in the pores of the porous zeolite.

[0049] The above-mentioned metal sulfur compound can be selected from at least one metal sulfate compound such as CuSO4, MnSO4, CeSO4, FeSO4, etc.

[0050] In the above stirring step, the stirring method is not particularly limited, and generally known methods can be used.

[0051] The mixed solution of the aqueous solution of the metal sulfide compound and the porous material may be stirred at 25° C. to 50° C. or 40° C. to 50° C. for 30 minutes to 2 hours, or 45 minutes to 1 hour.

[0052] After the stirring step, the mixed solution may further include filtering, washing and drying the solid matter.

[0053] The drying step may be performed at a temperature of 120° C. or above, 130° C. or above, or 120° C. to 200° C. The drying device may be an oven or a hot air drying belt mixer, but is not limited thereto.

[0054] Furthermore, according to another embodiment of the present invention, a blowing agent composition comprising a blowing agent and the formamide reducing additive may be provided.

[0055] According to yet another embodiment, a foaming composition comprising a resin and the foaming agent composition may be provided. Specifically, a foaming composition may be provided, comprising the foaming agent composition and a foaming resin, wherein the foaming resin comprises at least one selected from the group consisting of polyethylene, polypropylene, polyvinyl chloride, polycarbonate, polystyrene, polyamide, polyoxymethylene, styrene-butadiene rubber, ethylene-vinyl acetate copolymer (EVA), ethylene-propylene rubber, thermoplastic elastomer, thermoplastic polyurethane, thermoplastic rubber, ABS resin, rubber, epoxy resin, and acrylic resin.

[0056] The formamide reducing additives described above may be included in the blowing agent to reduce the formamide concentration of the blowing agent itself.

[0057] Furthermore, when the blowing agent composition is applied to a foaming target resin, the concentration of residual formamide in the foamed resin can be reduced after the foaming of the foaming target resin.

[0058] In one embodiment of the present invention, the residual formamide concentration of the foaming agent composition may be 10,000 ppm or less. Furthermore, the residual formamide concentration of the foamed resin in the foamed article may be 900 ppm or less.

[0059] The blowing agent composition may include 85 to 98 wt % of the blowing agent and 2 to 15 wt % of the formamide reducing additive.

[0060] That is, the content of the formamide-reducing additive can be 2% to 15% by weight relative to the total weight of the blowing agent composition. In the present invention, by including the formamide-reducing additive within the above content range, side effects can be reduced compared to the applied addition amount, and the formamide reduction effect can be maximized.

[0061] When the content of the formamide-reducing additive is less than 2% by weight, the degree of reduction in formamide concentration is reduced. Conversely, when the content exceeds 15% by weight, although the degree of reduction in formamide concentration is increased, the amount of blowing agent gas is reduced, resulting in a decrease in the foaming volume of the foamed product, hindering the crosslinking reaction and causing changes in physical properties.

[0062] Specifically, the content of the formamide-reducing additive can be 2 wt % to 10 wt % relative to the total weight of the blowing agent composition. In these cases, side effects are minimized and the reduction of formamide can be increased.

[0063] The foaming agent may be azodicarbonamide (ADCA) particles having an average particle size of 1 μm to 20 μm. Specifically, the foaming agent may be ADCA particles having an average particle size of 2 μm to 15 μm.

[0064] When the average particle size of the foaming agent is less than 1 μm, the foaming agent may be prematurely decomposed. When the average particle size of the foaming agent exceeds 20 μm, the foam cells of the foam may become uneven.

[0065] The resin is a foaming target resin used by the foaming agent, and may be, for example, polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polycarbonate (PC), polystyrene (PS), polyamide, polyoxymethylene, styrene-butadiene rubber (SBR), ethylene-vinyl acetate copolymer (EVA), ethylene-propylene rubber (EPDM), thermoplastic elastomer (TPE), thermoplastic polyurethane (TPU), thermoplastic rubber (TPR), acrylonitrile-butadiene-styrene copolymer (ABS), rubber, epoxy resin, acrylic resin, or other synthetic or natural resins. Specifically, the foaming target resin may be EVA. In one embodiment of the present invention, the foaming agent composition may further include an additive.

[0066] For example, the additive may include at least one selected from the group consisting of calcium compounds such as calcium stearate and calcium carbonate (CAS No. 471-34-1), zinc compounds such as zinc oxide and zinc stearate, titanium or tin compounds such as titanium dioxide and tin methoxy maleate, barium compounds such as barium stearate and barium ricinoleate, magnesium compounds such as magnesium oxide, talc, monosodium citrate, urea, silica, dicyclohexyl phthalate, and stearic acid. The calcium compound can improve the fluidity of the foaming agent, the zinc compound can promote the decomposition temperature, and the titanium or tin compound can improve the whiteness of the foam.

[0067] The content of the above additives can be within the range known in the art without particular limitation. For example, the content thereof can be 0.1 to 10 parts by weight relative to 100 parts by weight of the foaming agent composition.

[0068] On the other hand, according to yet another embodiment of the present invention, there is provided a foamed product having a residual formamide concentration of 900 ppm or less in a resin foamed by foaming the foaming composition.

[0069] When the formamide reducing additive for a blowing agent of the present invention is used to prepare a foam, the residual formamide content in the foam can be reduced to below 1000 ppm required by the industry more effectively than before without causing side effects of the foam and changes in the foaming properties.

[0070] Specifically, the residual formamide concentration of the foamed resin in the foam can be reduced to 900 ppm or less, 850 ppm or less, 600 ppm or less, 500 ppm or less, 400 ppm or less, 350 ppm or less, 300 ppm or less, 250 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 40 ppm or less, or 30 ppm or less.

[0071] Effects of the Invention

[0072] The formamide reducing additive for a blowing agent according to the present invention can significantly reduce the formamide concentration generated during the foaming process of a blowing agent (eg, ADCA) by impregnating at least one metal into porous zeolite.

[0073] In addition, the formamide reducing additive can also reduce the residual formamide concentration in the blowing agent (eg, ADCA) and the finished foam including the resin to below 900 ppm, thereby reducing environmental problems caused by formamide release. DETAILED DESCRIPTION

[0074] Best Mode for Carrying Out the Invention

[0075] In the following, examples are given to help understand the present invention. However, the following examples are only used to illustrate the present invention and are not used to limit the present invention.

[0076] <Examples 1 to 20 and Comparative Examples 1 to 7: Preparation of Formamide-Reducing Additives for Blowing Agents>

[0077] Metal sulfate compounds such as CuSO4, MnSO4, CeSO4, FeSO4, Cs2SO4, CoSO4·H2O, ZnSO4, NiSO4, Zr(SO4)2, Al2(SO4)3, and Si(SO4)2 were prepared.

[0078] Subsequently, the metal sulfate compound was dissolved in water so as to contain the first metal or the first metal and the second metal in the composition and content shown in Table 1 relative to the weight of the zeolite, and stirred for 30 minutes to completely dissolve it, thereby preparing a metal sulfate aqueous solution containing one or two metals, respectively.

[0079] Then, 4A zeolite (product of Cosmo Catalyst Co., Ltd.) was added to the metal sulfate aqueous solution and stirred for 2 hours, and then the product was filtered and washed with water.

[0080] At this time, if the metal is completely loaded in the zeolite, confirm whether the zeolite and the wastewater change color, and dry the filtered and washed zeolite in a vacuum oven at a temperature of 130° C. or higher for more than 4 hours to prepare the additive.

[0081] When two metals are contained, a method is adopted in which two aqueous solutions of sulfates of the relevant metals are mixed and then zeolite is added.

[0082] Comparative Example 4 adopts a method in which a silicon tetrachloride (Silicon (IV) chloride) aqueous solution and a CoSO 4 ·H 2 O aqueous solution are mixed and then zeolite is added.

[0083] <Examples 21 to 42 and Comparative Examples 8 to 17: Preparation of Foaming Agent Compositions>

[0084] According to the compositions and contents shown in Table 2, using azodicarbonamide (ADCA) and the formamide-reducing additives of Examples 1 to 20 and Comparative Examples 1 to 7, blowing agent compositions of Examples 21 to 42 and Comparative Examples 8 to 17 were prepared.

[0085] Azodicarbonamide (ADCA): dry product purity 100%, particle size 6-9 μm (Unicell D600, manufacturer: Dongjin Semichem), foaming performance parameters: decomposition temperature (DT) of 206°C, gas volume (GV) of 240 mL / g, application temperature of 210°C.

[0086] Next, each foam was prepared according to the following method.

[0087] Comparative Example 8

[0088] To 100 parts by weight of EVA sole resin, 5 parts by weight (phr) of a foaming agent composition consisting solely of ADCA, 10 parts by weight (phr) of a hard foaming agent, 1 part by weight of ZnO, 1 part by weight of stearic acid, and 1 part by weight of a crosslinking agent were added as additives to prepare a foaming composition (EVA composition). The foaming composition was then rolled into a sheet using a roller. The sheet was then placed under a pressure of 150 kgf / cm 2 The foam was hot-pressed at 175° C. for 12 minutes in a press to obtain a foam.

[0089] Comparative Example 9

[0090] A foam was prepared in the same manner as in Comparative Example 8, except that a blowing agent composition comprising 84 wt % of ADCA and 16 wt % of the formamide-reducing additive of Example 8 was used.

[0091] However, in Comparative Example 9, the occurrence of foam defects due to a decrease in expansion ratio and poor cross-linking was confirmed.

[0092] Comparative Example 10

[0093] A foam was prepared in the same manner as in Comparative Example 8, except that a blowing agent composition comprising 99 wt % of ADCA and 1 wt % of the formamide-reducing additive of Example 8 was used.

[0094] Comparative Examples 11 to 17

[0095] A foam was prepared in the same manner as in Comparative Example 8, except that a blowing agent composition including ADCA and the formamide-reducing additives of Comparative Examples 1 to 7 according to the composition and content shown in Table 2 below was used.

[0096] Example 21

[0097] A blowing agent composition was prepared by mixing 90 wt % ADCA and 10 wt % of the formamide reducing additive of Example 1.

[0098] To 100 parts by weight of EVA sole resin, 5 parts by weight (phr) of the above-mentioned foaming agent composition, 10 parts by weight (phr) of a hard foaming agent, 1 part by weight of ZnO, 1 part by weight of stearic acid, and 1 part by weight of a cross-linking agent were added as additives to prepare a foaming composition (EVA composition), which was then formed into a sheet by a roller. The sheet was then placed under a pressure of 150 kgf / cm 2 The foam was hot-pressed at 175° C. for 12 minutes in a press to obtain a foam.

[0099] Example 22 to Example 42

[0100] A foam was prepared in the same manner as in Example 21, except that a blowing agent composition including ADCA and the formamide-reducing additives of Examples 2 to 12 according to the composition and content in Table 2 below was used.

[0101] <Experimental Example>

[0102] Formamide analysis method

[0103] The residual formamide concentrations of the blowing agent compositions and foams of Examples 22 to 42 and Comparative Examples 8 to 17, as well as the residual formamide concentrations of the EVA foams, were analyzed. The results are shown in Table 2.

[0104] 1) The foamed body was cut into a size of 5 mm×5 mm, and 2 g of the foam was taken and added to 20 mL of acetone.

[0105] 2) The sample prepared in 1) above was dispersed in water at 40° C. for 1 hour using an ultrasonic oscillator.

[0106] 3) A small amount of acetone was taken from the dispersion obtained in 2) above and the formamide concentration was analyzed by GC-MS.

[0107] *Residual formamide concentration: The formamide concentration in the residue after foaming the ACDA blowing agent composition itself was analyzed without applying ADCA to the resin.

[0108] *Residual formamide concentration in EVA foam: refers to the residual formamide concentration in the foam obtained by foaming ADCA and EVA (i.e., the residual formamide concentration in the foam when EVA is mixed with a blowing agent composition and foamed).

[0109] Table 1

[0110]

[0111]

[0112] Table 2

[0113]

[0114]

[0115] According to the results in Table 2 above, Examples 21 to 42 employed the formamide-reducing additives of Examples 1 to 20, which impregnate zeolite with Cu ions within a specific content range as the first metal. Consequently, compared to Comparative Examples 8 to 17, the residual formamide concentrations in Examples 21 to 42 were lower overall, and the residual formamide concentrations in the EVA foam were all below 900 ppm, meeting the industry-required level of below 1000 ppm. In contrast, Comparative Example 8, which contained only ADCA, exhibited higher residual formamide concentrations, as well as higher residual formamide concentrations in the EVA.

[0116] Furthermore, although the formamide-reducing additive of Example 8 was used in Comparative Example 9, which somewhat reduced the residual formamide concentration and the residual formamide concentration in the EVA, the formamide-reducing additive content, at 16% by weight, exceeded the range specified in the present invention. This excessive content resulted in a decreased expansion ratio and poor cross-linking. Consequently, the foam of Comparative Example 9 suffered damage and failed to function properly.

[0117] In Comparative Example 10, although the residual formamide concentration of EVA is below 1000 ppm, the formamide reduction additive content is only 1 wt %, which is too low. Compared with the examples, the formamide reduction value is lower, so the formamide removal effect is very small.

[0118] Furthermore, Comparative Example 11 used the additive of Comparative Example 1 in which Cu as the first metal was impregnated at an excessively low content of 0.5 wt % (i.e., a formamide-reducing additive in which 0.5 wt % of Cu as the first metal was impregnated in 99.5 wt % of 4A zeolite), and therefore, its formamide reduction value was low.

[0119] Comparative Example 12 used the additive of Comparative Example 2 in which Cu as the first metal was impregnated at an excessive content of 18 wt % (i.e., 18 wt % of Cu as the first metal was impregnated in 82 wt % of 4A zeolite with a formamide-reducing additive). Therefore, when the content exceeded 17%, Cu could not be impregnated, and more than 1% of Cu remained in the waste liquid.

[0120] Comparative Examples 13 to 16 used the formamide-reducing additives of Comparative Examples 3 to 6 in which the first metal containing no Cu ions was impregnated in zeolite, and therefore the residual formamide concentration in EVA was 1100 ppm or more.

[0121] Comparative Example 17 used the formamide-reducing additive of Comparative Example 7, in which 0.5 wt.% of Cu as the first metal and 9.5 wt.% of Mn as the second metal were impregnated in 90 wt.% 4A zeolite in ionic form. Although the formamide-reducing additive contained Mn ions as the second metal, the proportion of Cu ions as the first metal was less than 1 wt.%, which was too small. As a result, the EVA residual formamide concentration was reduced even lower than that of Comparative Example 11.

Claims

1. A formamide reducing additive for a foaming agent, characterized in that include: a porous zeolite comprising a plurality of pores; and A metal comprising a first metal contained and impregnated in part or all of the pores.

2. The formamide reducing additive for a foaming agent according to claim 1, characterized in that The first metal includes at least one metal selected from Group 11 metals.

3. The formamide reducing additive for a foaming agent according to claim 1, characterized in that The first metal includes Cu.

4. The formamide reducing additive for a blowing agent according to claim 1, wherein The above-mentioned metal further includes a second metal different from the first metal.

5. The formamide reducing additive for a blowing agent according to claim 4, characterized in that The second metal includes at least one selected from the group consisting of Group 1, Group 3 to Group 10, Group 12, and Group 13 metals.

6. The formamide reducing additive for a blowing agent according to claim 4, characterized in that The second metal includes at least one selected from the group consisting of Mn, Si, Cr, Ce, Cs, Fe, Co, Zn, Ni, Zr, and Al.

7. The formamide reducing additive for a blowing agent according to claim 4, characterized in that The weight ratio of the first metal to the second metal relative to the total content of the metals is 1:9 to 16.9:0.

1.

8. The formamide reducing additive for a blowing agent according to claim 1, wherein include: 83 wt% to 99 wt% of the porous zeolite; and 1% to 17% by weight of the above metals.

9. The formamide reducing additive for a blowing agent according to claim 1, wherein The average particle size of the porous zeolite is 1 μm to 20 μm.

10. A foaming agent composition, characterized in that include: A blowing agent and a formamide reducing additive according to claim 1.

11. The foaming agent composition according to claim 10, characterized in that include: 85 to 98 wt% of the above-mentioned blowing agent; and 2% to 15% by weight of the above-mentioned formamide-reducing additive.

12. The foaming agent composition according to claim 10, characterized in that The foaming agent includes azodicarbonamide having an average particle size of 1 μm to 20 μm.

13. A foaming composition, characterized in that The foaming agent composition according to claim 10 and a foaming target resin, wherein the foaming target resin comprises at least one selected from the group consisting of polyethylene, polypropylene, polyvinyl chloride, polycarbonate, polystyrene, polyamide, polyoxymethylene, styrene-butadiene rubber, ethylene-vinyl acetate copolymer, ethylene-propylene rubber, thermoplastic elastomer, thermoplastic polyurethane, thermoplastic rubber, ABS resin, rubber, epoxy resin and acrylic resin.

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