Foaming agent for extruded polystyrene foam, extruded polystyrene foam, and foaming method

Abstract

The present invention provides a blowing agent for producing extruded polystyrene foam having low lambda over time and low foam density. [Solution] The foaming agent comprises (a) a first co-foaming agent consisting of (a) about 50% to about 70% by weight of HFO and / or HFCO having three or four carbon atoms, (b) about 2% to about 15% by weight of methyl formate, (c) a second co-foaming agent consisting of about 20% to about 30% by weight of dimethyl ether, isobutane and combinations thereof, and (d) a third co-foaming agent consisting of about 2% to about 25% by weight of carbon dioxide, acetone and combinations thereof.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This invention relates to U.S. Provisional Application No. 63 / 114,948, filed Nov. 17, 2021, and U.S. Provisional Application No. 63 / 181,135, filed Apr. 28, 2020, and claims the benefit of their priorities, each of which is hereby incorporated by reference in its entirety.

[0002] (Field of the Invention) The present invention relates to compositions, methods, and systems that are useful in connection with extruded thermoplastic foams, particularly those that include blowing agents, foamable compositions, foams, and articles made of or comprising foams.

Background Art

[0003] It has been found that certain fluorocarbon fluids are widely used as blowing agents. Due to environmental problems associated with some of the uses of fluorocarbon fluids that have been used heretofore in these applications, such as hydrofluorocarbons ("HFCs"), it is becoming increasingly desirable to use fluids having a low or even zero ozone depletion potential. However, some HFC fluids may have a relatively high global warming potential associated with them, and it is desirable to use hydrofluorocarbons or other fluorinated fluids having a low ozone depletion potential and a low global warming potential while maintaining the desired performance characteristics of the foam. With respect to the performance characteristics of foams, it is often considered important for the foam to have excellent thermal insulation properties and other desirable foam characteristics when used as a blowing agent. Another foam characteristic that is important in many applications is the density of the foam. For example, in many thermal insulation foam applications, it is necessary to have a foam that exhibits not only a low thermal conductivity but also a relatively low foam density.

[0004] ​

[0005] Therefore, there is a growing need for novel compounds and compositions that are attractive alternatives to the compositions that have been used as blowing agents in these and other applications. Accordingly, the applicants recognized the need for new blowing agent compositions that would provide effective alternatives to blowing agents conventionally used to produce low-density, low-thermal-conductivity thermoplastic foams, specifically extruded polystyrene foams, and that are considered to be more environmentally safe alternatives.

[0006] For example, the use of halogenated olefin blowing agents, including hydrofluoroolefins (HFOs) and hydrochlorofluoroolefins (HCFOs), is also known, as disclosed in U.S. Patent Application Publication No. 2009 / 0305876, which has been assigned to the assignee of the present invention and is incorporated herein by reference.

[0007] Notwithstanding the disclosures in each of '876, the applicants have found that hydrofluoroolefins, specifically one or more HFOs and / or HFCOs having three or four carbon atoms, such as trans-HFO-1234ze, trans-HCFO-1233zd, and cis-1,1,1,4,4,4-hexafluorobuta-2-ene (HFO-1336mzzm(Z)), are used as a first co-foaming agent consisting of methyl formate, isobutene, and / or dimethyl ether. We have come to recognize that by using a second co-foaming agent and at least a third foaming agent consisting of carbon dioxide and / or acetone in combination, unexpected advantages can be achieved in relation to the formation of extruded thermoplastic foams, particularly extruded polystyrene foams. [Overview of the Initiative]

[0008] The present invention relates to a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) Approximately 50% to 70% by weight of one or more HFOs having three or four carbon atoms and / or HFCOs having three or four carbon atoms, (b) A first co-foaming agent consisting essentially of methyl formate, ethanol, and combinations thereof in an amount of approximately 5% to 20% by weight, (c) A second co-foaming agent consisting of approximately 20% to 40% by weight of dimethyl ether, isobutane, and combinations thereof, (d) A third co-blown agent consisting of approximately 2% to 5% by weight of carbon dioxide, provided that the sum of (a), (b), (c), and (d) constitutes at least approximately 90% by weight of the blowing agent. For convenience, the blowing agent according to this paragraph will be referred to as blowing agent 1A.

[0009] The present invention relates to a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) Approximately 50% to 70% by weight of one or more HFOs having three or four carbon atoms and / or HFCOs having three or four carbon atoms, (b) A first co-foaming agent consisting essentially of methyl formate, ethanol, and combinations thereof in an amount of approximately 5% to 20% by weight, (c) A second co-foaming agent consisting of approximately 20% to 40% by weight of dimethyl ether, isobutane, and combinations thereof, (d) A third co-blown agent consisting of approximately 2% to 5% by weight of carbon dioxide, provided that the sum of (a), (b), (c), and (d) constitutes at least approximately 95% by weight of the blowing agent. For convenience, the blowing agent according to this paragraph shall be referred to as blowing agent 1B.

[0010] The present invention relates to a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) Approximately 50% to 70% by weight of one or more HFOs having three or four carbon atoms and / or HFCOs having three or four carbon atoms, (b) A first co-foaming agent consisting essentially of methyl formate, ethanol, and combinations thereof in an amount of approximately 5% to 20% by weight, (c) A second co-foaming agent consisting of approximately 20% to 40% by weight of dimethyl ether, isobutane, and combinations thereof, (d) A third co-blown agent consisting of approximately 2% to 5% by weight of carbon dioxide, provided that the sum of (a), (b), (c), and (d) constitutes at least approximately 97% by weight of the blowing agent. For convenience, the blowing agent according to this paragraph will be referred to as blowing agent 1C.

[0011] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) HFOs and / or HFCOs having 3 or 4 carbon atoms in an amount of approximately 50% to 65% by weight, (b) A first co-foaming agent consisting essentially of methyl formate, ethanol, and combinations thereof in an amount of approximately 5% to 15% by weight, (c) A second co-foaming agent consisting of approximately 20% to 35% by weight of dimethyl ether, isobutane, and combinations thereof, (d) A blowing agent comprising a third co-blowing agent essentially consisting of less than approximately 5% by weight of carbon dioxide. For convenience, the blowing agent according to this paragraph will be referred to as blowing agent 2A in this specification.

[0012] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) HFOs and / or HFCOs having 3 or 4 carbon atoms in an amount of approximately 50% to 65% by weight, (b) A first co-foaming agent consisting essentially of methyl formate, ethanol, and combinations thereof in an amount of approximately 5% to 15% by weight, (c) A second co-foaming agent consisting of approximately 20% to 35% by weight of dimethyl ether, isobutane, and combinations thereof, (d) A blowing agent comprising a third co-blowing agent essentially consisting of less than 5% by weight of carbon dioxide. For convenience, the blowing agent according to this paragraph will be referred to as blowing agent 2B.

[0013] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) 1234 ze(E) in approximately 55% to 65% by weight, (b) Approximately 5% to 15% by weight of methyl formate, (c) Approximately 20% to 25% by weight of dimethyl ether, isobutane, and combinations thereof, (d) Contains a blowing agent comprising approximately 3% to 5% by weight of carbon dioxide. For convenience, the blowing agent described in this paragraph shall be referred to as blowing agent 3A in this specification.

[0014] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) 1234 ze(E) in approximately 55% to 65% by weight, (b) A first co-foaming agent consisting essentially of about 5% to 15% by weight of methyl formate, (c) A second co-foaming agent consisting essentially of approximately 20% to 25% by weight of dimethyl ether and combinations thereof, (d) A blowing agent comprising a third co-blowing agent essentially consisting of about 3% to about 5% by weight of carbon dioxide. For convenience, the blowing agent according to this paragraph will be referred to as blowing agent 3B in this specification.

[0015] The present invention also relates to a blowing agent for producing a thermoplastic foam having excellent heat insulation properties (preferably including a low lambda over time) and a low foam density, the blowing agent comprising (a) from about 55% to about 65% by weight of 1234ze(E), (b) a first co-blowing agent consisting essentially of from about 5% to about 15% by weight of methyl formate, (c) a second co-blowing agent consisting essentially of from about 20% to about 25% by weight of dimethyl ether and combinations thereof, (d) a third co-blowing agent consisting essentially of from about 3% to about 5% by weight of carbon dioxide, provided that the sum of (a), (b), (c) and (d) constitutes at least about 97% by weight of the blowing agent. For convenience, in this specification, the blowing agent according to this paragraph is referred to as blowing agent 3C.

[0016] The present invention also relates to a blowing agent for producing a thermoplastic foam having excellent heat insulation properties (preferably including a low lambda over time) and a low foam density, the blowing agent comprising (a) from about 45% to about 65% by weight of 1234ze(E), 1233zd(E) and combinations thereof, (b) a first co-blowing agent consisting essentially of from about 5% to about 15% by weight of methyl formate, ethanol or combinations thereof, (c) a second co-blowing agent consisting essentially of from about 25% to about 40% by weight of dimethyl ether, isobutane and combinations thereof, [[ID=答案:20]](d) a third co-blowing agent consisting essentially of from about 3% to about 5% by weight of carbon dioxide.

[0017] The present invention also relates to a blowing agent for producing a thermoplastic foam having excellent heat insulation properties (preferably including a low lambda over time) and a low foam density, the blowing agent comprising (a) from about 45% to about 65% by weight of 1234ze(E), 1233zd(E) and combinations thereof, (b) A first co-foaming agent consisting of approximately 5% to 15% by weight of methyl formate, ethanol, or a combination thereof, (c) A second co-foaming agent consisting essentially of dimethyl ether, isobutane, and combinations thereof in an amount of approximately 25% to 40% by weight, (d) A third co-blown agent consisting of approximately 3% to 5% by weight of carbon dioxide, provided that the sum of (a), (b), (c), and (d) constitutes at least approximately 97% by weight of the blowing agent. For convenience, the blowing agent according to this paragraph shall be referred to as blowing agent 4A2.

[0018] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) 1234ze(E), 1233zd(E), and combinations thereof in amounts of approximately 45% to 65% by weight, (b) A first co-foaming agent consisting essentially of about 5% to 15% by weight of methyl formate, (c) A second co-foaming agent consisting essentially of approximately 25% to 40% by weight of isobutane and combinations thereof, (d) A blowing agent comprising a third co-blowing agent essentially consisting of about 3% to about 5% by weight of carbon dioxide. For convenience, the blowing agent according to this paragraph will be referred to as blowing agent 4B in this specification.

[0019] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) 1234ze(E), 1233zd(E), and combinations thereof in amounts of approximately 45% to 65% by weight, (b) A first co-foaming agent consisting essentially of about 5% to 15% by weight of methyl formate, (c) A second co-foaming agent consisting essentially of approximately 30% to 40% by weight of isobutane and combinations thereof, (d) A blowing agent comprising a third co-blowing agent essentially consisting of about 3% to about 5% by weight of carbon dioxide. For convenience, the blowing agent according to this paragraph will be referred to as blowing agent 4C in this specification.

[0020] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) Approximately 50% to 60% by weight of 1234ze(E), 1233zd(E), and combinations thereof, (b) A first co-foaming agent consisting essentially of about 5% to 15% by weight of ethanol, (c) A second co-foaming agent consisting essentially of approximately 25% to 40% by weight of isobutane and combinations thereof, (d) A blowing agent comprising a third co-blowing agent essentially consisting of about 3% to about 5% by weight of carbon dioxide. For convenience, the blowing agent according to this paragraph will be referred to as blowing agent 4D in this specification.

[0021] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) Approximately 50% to 60% by weight of 1234ze(E), 1233zd(E), and combinations thereof, (b) A first co-foaming agent consisting essentially of about 5% to 15% by weight of ethanol, (c) A second co-foaming agent consisting essentially of approximately 25% to 35% by weight of isobutane and combinations thereof, (d) A blowing agent comprising a third co-blowing agent essentially consisting of about 3% to about 5% by weight of carbon dioxide. For convenience, the blowing agent according to this paragraph will be referred to as blowing agent 4E1 in this specification.

[0022] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) Approximately 50% to 60% by weight of 1234ze(E), 1233zd(E), and combinations thereof, (b) A first co-foaming agent consisting essentially of about 5% to 15% by weight of ethanol, (c) A second co-foaming agent consisting essentially of approximately 25% to 35% by weight of isobutane and combinations thereof, (d) A third co-blown agent consisting of approximately 3% to 5% by weight of carbon dioxide, provided that the sum of (a), (b), (c), and (d) constitutes at least approximately 97% by weight of the blowing agent. For convenience, the blowing agent according to this paragraph shall be referred to as blowing agent 4E2.

[0023] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a1) 1234 ze(E) in approximately 30% to 50% by weight, (a2) 1233zd(E) in approximately 10% to 20% by weight, (b) Approximately 5% to 20% by weight of methyl formate, ethanol, or a combination thereof, (c) Approximately 20% to 40% by weight of dimethyl ether, isobutane, and combinations thereof, (d) Contains a blowing agent comprising approximately 3% to 5% by weight of carbon dioxide. For convenience, the blowing agent described in this paragraph shall be referred to as blowing agent 4F1 in this specification.

[0024] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a1) 1234 ze(E) in approximately 30% to 50% by weight, (a2) 1233zd(E) in approximately 10% to 20% by weight, (b) Approximately 5% to 20% by weight of methyl formate, ethanol, or a combination thereof, (c) Approximately 20% to 40% by weight of dimethyl ether, isobutane, and combinations thereof, (d) A blowing agent comprising approximately 3% to 5% by weight of carbon dioxide, provided that the sum of (a), (b), (c), and (d) constitutes at least approximately 97% by weight of the blowing agent. For convenience, the blowing agent according to this paragraph shall be referred to as blowing agent 4F2 in this specification.

[0025] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a1) 1234 ze(E) in approximately 30% to 50% by weight, (a2) 1233zd(E) in approximately 10% to 20% by weight, (b) Approximately 5% to 20% by weight of methyl formate, (c) Approximately 20% to 40% by weight of isobutane, (d) Contains a blowing agent comprising approximately 3% to 5% by weight of carbon dioxide. For convenience, the blowing agent described in this paragraph shall be referred to as blowing agent 4G1.

[0026] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a1) 1234 ze(E) in approximately 30% to 50% by weight, (a2) 1233zd(E) in approximately 10% to 20% by weight, (b) Approximately 5% to 20% by weight of methyl formate, (c) Approximately 20% to 40% by weight of isobutane, (d) A blowing agent comprising approximately 3% to 5% by weight of carbon dioxide, provided that the sum of (a), (b), (c), and (d) constitutes at least approximately 97% by weight of the blowing agent. For convenience, the blowing agent according to this paragraph shall be referred to as blowing agent 4G2 in this specification.

[0027] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a1) Approximately 40% by weight of 1234ze(E), (a2) Approximately 13% by weight of 1233zd(E), (b) Approximately 10% by weight of methyl formate, (c) Approximately 33% by weight of isobutane, (d) Contains a blowing agent comprising approximately 3% to 5% by weight of carbon dioxide. For convenience, the blowing agent described in this paragraph shall be referred to as blowing agent 4H.

[0028] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a1) 1234 ze(E) in approximately 30% to 50% by weight, (a2) 1233zd(E) in approximately 10% to 20% by weight, (b) Approximately 5% to 15% by weight of ethanol, (c) Approximately 30% to 40% by weight of isobutane, (d) Contains a blowing agent comprising approximately 3% to 5% by weight of carbon dioxide. For convenience, the blowing agent according to this paragraph will be referred to as blowing agent 4I1 in this specification.

[0029] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a1) 1234 ze(E) in approximately 30% to 50% by weight, (a2) 1233zd(E) in approximately 10% to 20% by weight, (b) Approximately 5% to 15% by weight of ethanol, (c) Approximately 30% to 40% by weight of isobutane, (d) A blowing agent comprising approximately 3% to 5% by weight of carbon dioxide, provided that the sum of (a), (b), (c), and (d) constitutes at least approximately 97% by weight of the blowing agent. For convenience, the blowing agent described in this paragraph shall be referred to as blowing agent 4I2.

[0030] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a1) 1234 ze(E) in approximately 30% to 50% by weight, (a2) 1233zd(E) in approximately 10% to 20% by weight, (b) Approximately 5% to 10% by weight of ethanol, (c) Approximately 30% to 40% by weight of isobutane, (d) Contains a blowing agent containing approximately 3% to 5% by weight of carbon dioxide. For convenience, the blowing agent described in this paragraph will be referred to as blowing agent 4J1 in this specification.

[0031] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a1) 1234 ze(E) in approximately 30% to 50% by weight, (a2) 1233zd(E) in approximately 10% to 20% by weight, (b) Approximately 5% to 10% by weight of ethanol, (c) Approximately 30% to 40% by weight of isobutane, (d) A blowing agent comprising approximately 3% to 5% by weight of carbon dioxide, provided that the sum of (a), (b), (c), and (d) constitutes at least approximately 97% by weight of the blowing agent. For convenience, the blowing agent according to this paragraph shall be referred to as blowing agent 4J2 in this specification.

[0032] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a1) Approximately 41.5% by weight of 1234ze(E), (a2) Approximately 10% by weight of 1233zd(E), (b) Approximately 7% by weight of ethanol, (c) Approximately 35% by weight of isobutane, (d) Contains a blowing agent comprising approximately 3% to 5% by weight of carbon dioxide. For convenience, the blowing agent described in this paragraph shall be referred to as blowing agent 4K1.

[0033] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a1) Approximately 41.5% by weight of 1234ze(E), (a2) Approximately 10% by weight of 1233zd(E), (b) Approximately 7% by weight of ethanol, (c) Approximately 35% by weight of isobutane, (d) A blowing agent comprising approximately 3% to 5% by weight of carbon dioxide, provided that the sum of (a), (b), (c), and (d) constitutes at least approximately 97% by weight of the blowing agent. For convenience, the blowing agent described in this paragraph shall be referred to as blowing agent 4K2.

[0034] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a1) 1234 ze(E) in approximately 30% to 50% by weight, (a2) 1233zd(E) in approximately 10% to 20% by weight, (b) Approximately 7% to 15% by weight of ethanol, (c) Approximately 30% to 40% by weight of isobutane, (d) Contains a blowing agent comprising approximately 3% to 5% by weight of carbon dioxide. For convenience, the blowing agent described in this paragraph shall be referred to as blowing agent 4L1 in this specification.

[0035] The present invention also offers excellent thermal insulation properties (preferably including low lambda over time) and low foaming. A blowing agent for producing a thermoplastic foam having a body density, wherein the blowing agent is (a1) 1234 ze(E) in approximately 30% to 50% by weight, (a2) 1233zd(E) in approximately 10% to 20% by weight, (b) Approximately 7% to 15% by weight of ethanol, (c) Approximately 30% to 40% by weight of isobutane, (d) A blowing agent comprising approximately 3% to 5% by weight of carbon dioxide, provided that the sum of (a), (b), (c), and (d) constitutes at least approximately 97% by weight of the blowing agent. For convenience, the blowing agent according to this paragraph shall be referred to as blowing agent 4L2 in this specification.

[0036] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a1) Approximately 40% by weight of 1234ze(E), (a2) Approximately 13% by weight of 1233zd(E), (b) Approximately 10% by weight of ethanol, (c) Approximately 33% by weight of isobutane, (d) Contains a blowing agent comprising approximately 3% to 5% by weight of carbon dioxide. For convenience, the blowing agent described in this paragraph shall be referred to as blowing agent 4M.

[0037] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) 1233zd(E) in approximately 45% to 65% by weight, (b) Approximately 5% to 15% by weight of methyl formate, (c) Approximately 15% to 35% by weight of isobutane, (d) Contains a blowing agent comprising approximately 3% to 5% by weight of carbon dioxide. For convenience, the blowing agent described in this paragraph shall be referred to as blowing agent 5A1 in this specification.

[0038] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) 1233zd(E) in approximately 45% to 65% by weight, (b) Approximately 5% to 15% by weight of methyl formate, (c) Approximately 15% to 35% by weight of isobutane, (d) A blowing agent comprising approximately 3% to 5% by weight of carbon dioxide, provided that the sum of (a), (b), (c), and (d) constitutes at least approximately 97% by weight of the blowing agent. For convenience, the blowing agent according to this paragraph shall be referred to as blowing agent 5A2 in this specification.

[0039] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) Approximately 61.5% by weight of 1233zd(E), (b) Approximately 11.5% by weight of methyl formate, (c) Approximately 23% by weight of isobutane, (d) Contains a blowing agent comprising approximately 3% to 5% by weight of carbon dioxide. For convenience, the blowing agent according to this paragraph shall be referred to as blowing agent 5B in this specification.

[0040] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) 1234 ze(E) in approximately 45% to 65% by weight, (b) Approximately 5% to 15% by weight of methyl formate, (c) Approximately 15% to 35% by weight of isobutane, (d) Contains a blowing agent comprising approximately 3% to 5% by weight of carbon dioxide. For convenience, the blowing agent described in this paragraph shall be referred to as blowing agent 6A1 in this specification.

[0041] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) 1234 ze(E) in approximately 45% to 65% by weight, (b) Approximately 5% to 15% by weight of methyl formate, (c) Approximately 15% to 35% by weight of isobutane, (d) A blowing agent comprising approximately 3% to 5% by weight of carbon dioxide, provided that the sum of (a), (b), (c), and (d) constitutes at least approximately 97% by weight of the blowing agent. For convenience, the blowing agent according to this paragraph shall be referred to as blowing agent 6A2 in this specification.

[0042] The present invention also provides a blowing agent for producing a thermoplastic foam having excellent thermal insulation properties (preferably including low lambda over time) and low foam density, wherein the blowing agent is (a) Approximately 61.5% by weight of 1234ze(E), (b) Approximately 11.5% by weight of methyl formate, (c) Approximately 23% by weight of isobutane, (d) Contains a blowing agent comprising approximately 3% to 5% by weight of carbon dioxide. For convenience, the blowing agent described in this paragraph shall be referred to as blowing agent 6B in this specification.

[0043] The present invention also includes a method for forming a foam using the blowing agents of the present invention, which include blowing agents 1 to 6, and the present invention also includes a foam produced by a method containing and / or using the blowing agents of the present invention, which include blowing agents 1 to 6, as described in detail herein. Where used herein, a reference to a defined blowing agent or a range of defined blowing agents, such as blowing agents 1 to 6, includes all such defined blowing agents, including, for example, blowing agent 2 meaning blowing agent 2A and blowing agent 2B, and blowing agent 6 meaning blowing agent 6A1, blowing agent 6A2 and 6B, and any numbered blowing agents with suffixes. [Brief explanation of the drawing]

[0044] [Figure 1] Figure 1 is a schematic diagram of an extrusion system and process according to an embodiment of the present invention and the embodiments thereof. [Figure 2] Figure 2 is a graph showing the test results from Comparative Examples 1A and 1B. [Figure 3] Figure 3 is a graph showing the test results from Example 1. [Figure 4] Figure 4 is a graph showing the test results from Example 2. [Figure 5] Figure 5 is a graph showing the test results from Example 3. [Figure 6A] Figure 6A is a graph showing the test results from Example 6(A). [Figure 6B] Figure 6B is a graph showing the test results from Example 6(B).

[0045] definition 1234ze means 1,1,1,3-tetrafluoropropene and is not limited to isomer morphology.

[0046] Trans-1234ze and 1234ze(E) refer to trans-1,3,3,3-tetrafluoropropene, respectively.

[0047] 1234yf stands for 2,3,3,3-tetrafluoropropene.

[0048] 1233zd stands for 1-chloro-3,3,3-trifluoropropene, and is an isomer. Not limited in terms of form.

[0049] Trans-1233zd and 1233zd(E) refer to trans-1-chloro-3,3,3-trifluoropropene, respectively.

[0050] cis1224yd means cis-1-chloro-2,3,3,3-tetrafluoropropane.

[0051] cis-1336mzz and 1336mzz(Z) each refer to cis-1,1,1,4,4,4-hexafluorobutene, and are not limited to isomer morphology.

[0052] Trans-1336mzz and 1336mzz(E) refer to trans-1,1,1,4,4,4-hexafluorobutene, respectively. Methyl formate is the following compound

[0053] [ka] It means...

[0054] Methylal refers to dimethoxymethane ((CH3O)2CH2).

[0055] Dimethyl ether is the following compound

[0056] [ka] It means...

[0057] Isobutane, iC4, and isoC4 each refer to 2-methylpropane.

[0058] Ethanol and EtOH both refer to CH3CH2OH.

[0059] A closed-cell foam means that the substantial volume percentage of the bubbles in the foam, for example, about 20% or more by volume, are independent.

[0060] PS PEF homopolymer means a polymer having at least 99% by weight of an ethylene furanoate moiety.

[0061] PEF copolymer means a polymer having at least 50% by weight of ethylene furanoate and more than 1% of a polymer other than ethylene.

[0062] The styrene portion has the following structure

[0063] [ka] This refers to all compounds having and all compounds in which one or more hydrogens are substituted.

[0064] Polystyrene, polystyrene resin, and PS each mean polymers made from monomers containing a styrene portion, and include homopolymers, copolymers, and blends of polymers containing such homopolymers and / or copolymers.

[0065] XPS foam refers to polystyrene formed into a foam through an extrusion process.

[0066] The thermal conductivity over time and the lambda over time refer to the measured thermal conductivity, as described in the examples.

[0067] Density refers to the foam density, as measured in the examples. [Modes for carrying out the invention]

[0068] foaming agent The blowing agents of the present invention, each comprising blowing agents 1 to 6, may also include one or more co-blowing agents other than those specified, provided that they are of a type and quantity that does not impair the ability of the blowing agent to form a polystyrene foam having the density and thermal conductivity characteristics described herein as an embodiment of the present invention, specifically, an XPS foam. Within this parameter range, and as just one example, the blowing agents of the present invention, each comprising blowing agents 1 to 6, may also include one or more of the following in addition to the specifically specified components of the blowing agent: saturated hydrocarbons having 3 to 5 carbon atoms such as propane, n-butane, and cyclopentane; ethers such as ethyl ether, diethyl ether, and methyl ethyl ether; alkyl chlorides such as methyl chloride and ethyl chloride; alcohols such as methanol, propyl alcohol, isopropyl alcohol, butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, aryl alcohol, clotyl alcohol, and propargyl alcohol; ketones; and esters.

[0069] Other additives may also be included, insofar as they do not impair the type and amount of the blowing agent used to form polystyrene foam having the density and thermal conductivity characteristics described herein in aspects of the present invention, specifically XPS foam. Within these parameters, and as just one example, the blowing agent of the present invention, comprising each of blowing agents 1 to 6, may include one or more of the following: processing aids, flame retardants, colorants, stabilizers, surfactants, polymer modifiers, strengtheners, colorants, dyes, solubility enhancers, rheology modifiers, plasticizers, combustion inhibitors, antimicrobial agents, viscosity-reducing modifiers, fillers, vapor pressure modifiers, nucleating agents, catalysts, etc.

[0070] foam The present invention also includes a thermoplastic foam, preferably an XPS foam, which comprises a PS resin and a foaming agent of the present invention, each of which comprises one of the foaming agents 1 to 6.

[0071] The present invention relates to an XPS foam, (a) Thermoplastic polymer bubbles containing PS cell walls that form closed cells, (b) an XPS foam comprising a foaming agent 1 contained in closed cells. For convenience, the foam according to this paragraph will be referred to as foam 1 in this specification.

[0072] The present invention relates to an XPS foam, (a) Thermoplastic polymer bubbles containing PS cell walls that form closed cells, (b) an XPS foam comprising a foaming agent 2 contained in closed cells. For convenience, the foam according to this paragraph will be referred to as foam 2 in this specification.

[0073] The present invention relates to an XPS foam, (a) Thermoplastic polymer bubbles containing PS cell walls that form closed cells, (b) an XPS foam comprising a foaming agent 3 contained in closed cells. For convenience, the foam according to this paragraph will be referred to as foam 3 in this specification.

[0074] The present invention relates to an XPS foam, (a) Thermoplastic polymer bubbles containing PS cell walls that form closed cells, (b) an XPS foam comprising a foaming agent 4 contained in closed cells. For convenience, the foam according to this paragraph will be referred to as foam 4 in this specification.

[0075] The present invention relates to an XPS foam, (a) Thermoplastic polymer bubbles containing PS cell walls that form closed cells, (b) an XPS foam comprising a foaming agent 5 contained in closed cells. For convenience, the foam according to this paragraph will be referred to as foam 5 in this specification.

[0076] The present invention relates to an XPS foam, (a) Thermoplastic polymer bubbles containing PS cell walls that form closed cells, (b) an XPS foam comprising a foaming agent 6 contained in closed cells. For convenience, the foam according to this paragraph will be referred to as foam 6 in this specification.

[0077] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 36 kg / m³ or less and a thermal conductivity over time of 32 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 7A in this specification.

[0078] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 35 kg / m³ or less and a thermal conductivity over time of 32 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 7B.

[0079] The present invention comprises an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 34 kg / m³ or less and a thermal conductivity over time of 32 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 7C in this specification.

[0080] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 33 kg / m3 or less and a thermal conductivity over time of 32 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 7D in this specification.

[0081] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 32 kg / m3 or less and a thermal conductivity over time of 32 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 7E in this specification.

[0082] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 36 kg / m3 or less and a thermal conductivity over time of 31 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 8A in this specification.

[0083] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 35 kg / m³ or less and a thermal conductivity over time of 31 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 8B in this specification.

[0084] The present invention comprises an XPS foam containing each of foams 1 to 6, the foam having a density of 34 kg / m3 or less and a thermal conductivity over time of 31 mW / mk or less. For convenience, in this specification, The foam produced in this paragraph will be referred to as foam 8C.

[0085] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 33 kg / m3 or less and a thermal conductivity over time of 31 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 8D in this specification.

[0086] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 32 kg / m3 or less and a thermal conductivity over time of 31 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 8E in this specification.

[0087] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 36 kg / m3 or less and a thermal conductivity over time of 30 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 9A in this specification.

[0088] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 35 kg / m3 or less and a thermal conductivity over time of 30 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 9B in this specification.

[0089] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 34 kg / m3 or less and a thermal conductivity over time of 30 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 9C in this specification.

[0090] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 33 kg / m3 or less and a thermal conductivity over time of 30 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 9D in this specification.

[0091] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 32 kg / m³ or less and a thermal conductivity over time of 30 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 9E in this specification.

[0092] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 36 kg / m3 or less and a thermal conductivity over time of 29 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 10A in this specification.

[0093] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 35 kg / m3 or less and a thermal conductivity over time of 29 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 10B in this specification.

[0094] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 34 kg / m3 or less and a thermal conductivity over time of 29 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 10C in this specification.

[0095] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 33 kg / m3 or less and a thermal conductivity over time of 29 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 10D in this specification.

[0096] The present invention includes an XPS foam containing each of foams 1 to 6, wherein the foam has a density of 32 kg / m3 or less and a thermal conductivity over time of 29 mW / mk or less. For convenience, the foam according to this paragraph will be referred to as foam 10E in this specification.

[0097] The present invention includes an XPS foam containing each of foams 1 to 10, which are closed-cell foams. For convenience, the foam according to this paragraph will be referred to as foam 10F.

[0098] The present invention comprises an XPS foam containing each of foams 1 to 10, wherein the foam is a closed-cell foam having at least 50% by volume of closed cells. For convenience, the foam according to this paragraph will be referred to as foam 10G.

[0099] The present invention comprises an XPS foam containing each of foams 1 to 10, wherein the foam is a closed-cell foam having at least 90% by volume of closed cells. For convenience, the foam according to this paragraph will be referred to as foam 10H.

[0100] The styrene-based resin used in the present invention, which includes each of foams 1 to 10 and each of methods 1 to 11, is not particularly limited. Examples of styrene-based resins include homopolymers of styrene monomers such as styrene, methylstyrene, ethylstyrene, isopropylstyrene, dimethylstyrene, bromostyrene, chlorostyrene, vinyltoluene, and vinylxylene, or copolymers of two or more monomers obtained by copolymerizing styrene monomers with at least one or more monomers such as divinylbenzene, butadiene, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, acrylonitrile, maleic anhydride, and itaconic anhydride. Monomers copolymerized with styrene monomers such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, maleic anhydride, and itaconic anhydride can be used in a range that does not impair the compressive strength properties of the resulting extruded polystyrene foam. The styrene resin used in the present invention is not limited to homopolymers or copolymers of styrene monomers, but may be a blend of homopolymers or copolymers of other monomers, and diene-based rubber-reinforced polystyrene or acrylic-based rubber-reinforced polystyrene may be blended.

[0101] The styrene-based resin used in the present invention, which includes each of foams 1 to 10 and each of methods 1 to 11, is not particularly limited. Examples of styrene-based resins include homopolymers of styrene monomers such as styrene, methylstyrene, ethylstyrene, isopropylstyrene, dimethylstyrene, bromostyrene, chlorostyrene, vinyltoluene, and vinylxylene, or copolymers of two or more monomers obtained by copolymerizing styrene monomers with at least one or more monomers such as divinylbenzene, butadiene, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, acrylonitrile, maleic anhydride, and itaconic anhydride. Monomers copolymerized with styrene monomers such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, maleic anhydride, and itaconic anhydride can be used within a range that does not impair the physical properties of the resulting extruded polystyrene foam, such as its compressive strength. The styrene resin used in the present invention is not limited to homopolymers or copolymers of styrene monomers, but may be a blend of homopolymers or copolymers of other monomers, and may be a blend of diene-based rubber-reinforced polystyrene or acrylic-based rubber-reinforced polystyrene. The styrene resin used in the present invention may be a styrene resin having a branched structure for the purpose of adjusting the melt volume rate (hereinafter also referred to as MVR), melt viscosity and melt tension during molding, etc.

[0102] According to a preferred embodiment, the foam of the present invention, comprising each of foams 1 to 10, is preferably formed from a general-purpose styrene resin having an MVR of 0.1 to 50 g / 10 min. Such resins are preferred because they exhibit excellent moldability in extrusion foam molding and allow for the production of thermoplastic resin foams in which the extrusion rate, thickness and width of the resulting extruded polystyrene foam, apparent density, or closed-cell ratio can be adjusted to desired values. VR may contain 0.3 to 30 g / 10 min, or 0.5 to 25 g / 10. In this invention, MVR is measured according to ISO 1133.

[0103] In the present invention, among the styrene-based resins mentioned above, polystyrene-based resins are preferred from the viewpoint of economy and processability. When higher heat resistance is required for the extruded foam, it is preferable to use styrene-acrylonitrile copolymer, (meth)acrylic acid copolymer polystyrene, or maleic anhydride-modified polystyrene. When higher impact resistance is required for the extruded foam, it is preferable to use rubber-reinforced polystyrene. The styrene-based resin may be used alone, or two or more styrene-based resins with different copolymer components, molecular weight and molecular weight distribution, branched structure, MVR, etc., may be used as a mixture.

[0104] The PS used to form the foam, which includes each of foams 1 to 10, and used in accordance with the Method, which includes each of methods 1 to 11, may have properties within the broad, intermediate, and narrow ranges, respectively, as specified in the table below.

[0105] [Table 1]

[0106] method The applicants have found that by using the foaming agent of the present invention in the foam formation process, unexpected advantages can be achieved in the preparation of thermoplastic foams, each of which contains foam 1 to foam 10E.

[0107] In a particular embodiment, the present invention relates to a method for producing a thermoplastic XPS foam, (i) Providing PS, (ii) A method comprising foaming PS using any one of the foaming agents of the present invention, each comprising foaming agent 1 to foaming agent 6. For convenience, the method according to this paragraph will be referred to as Method 1.

[0108] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) To provide thermoplastic materials, (ii) Extruding thermoplastic materials, (iii) A method is provided comprising foaming a thermoplastic material using any one of the foaming agents of the present invention, each comprising foaming agent 1 to foaming agent 6. For convenience, the method according to this paragraph will be referred to as Method 2.

[0109] The present invention also relates to a method for foaming XPS, (i) To provide thermoplastic polystyrene, (ii) Extruding thermoplastic polystyrene, (iii) A method is provided comprising foaming a polystyrene foam using any one of the foaming agents of the present invention, each containing foaming agent 1 to foaming agent 6. For convenience, the method according to this paragraph will be referred to as Method 3.

[0110] The present invention also relates to a method for producing XPS foam, (i) Providing PS, (ii) A method is provided comprising foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 36 kg / m3 or less and a thermal conductivity over time of 32 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 4A in this specification.

[0111] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided for foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 35 kg / m3 or less and a thermal conductivity over time of 32 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 4B in this specification.

[0112] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided for foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 34 kg / m3 or less and a thermal conductivity over time of 32 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 4C in this specification.

[0113] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided for foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 33 kg / m3 or less and a thermal conductivity over time of 32 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 4D in this specification.

[0114] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided for foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 32 kg / m3 or less and a thermal conductivity over time of 32 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 4E in this specification.

[0115] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided for foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 31 kg / m3 or less and a thermal conductivity over time of 32 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 4F in this specification.

[0116] The present invention also relates to a method for producing XPS foam, (i) Providing PS, (ii) Foaming PS using any one of the foaming agents of the present invention, each containing foaming agent 1 to foaming agent 6, wherein the foam has a density of approximately 36 kg / m3 or less and 31 mW The present invention provides a method comprising foaming, which has a thermal conductivity over time of less than or equal to / mk. For convenience, the method according to this paragraph shall be referred to as Method 5A in this specification.

[0117] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided for foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 35 kg / m3 or less and a thermal conductivity over time of 31 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 5B in this specification.

[0118] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided for foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 34 kg / m3 or less and a thermal conductivity over time of 31 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 5C in this specification.

[0119] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided for foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 33 kg / m3 or less and a thermal conductivity over time of 31 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 5D in this specification.

[0120] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided comprising foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 32 kg / m3 or less and a thermal conductivity over time of 31 mW / mk or less. For convenience, the method according to this paragraph shall be referred to as Method 5E in this specification.

[0121] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided for foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 31 kg / m3 or less and a thermal conductivity over time of 31 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 5F in this specification.

[0122] The present invention also relates to a method for producing XPS foam, (i) Providing PS, (ii) A method is provided comprising foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 36 kg / m3 or less and a thermal conductivity over time of 30 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 6A in this specification.

[0123] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided for foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 35 kg / m3 or less and a thermal conductivity over time of 30 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 6B in this specification.

[0124] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided for foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 34 kg / m3 or less and a thermal conductivity over time of 30 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 6C in this specification.

[0125] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided for foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 33 kg / m3 or less and a thermal conductivity over time of 30 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 6D in this specification.

[0126] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided for foaming PS using any one of the foaming agents of the present invention, each of which comprises foaming agent 1 to foaming agent 6, wherein the foam has a density of about 32 kg / m3 or less and a thermal conductivity over time of 30 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 6E in this specification.

[0127] The present invention also relates to a method for forming an extruded thermoplastic foam, (i) Providing PS, (ii) Pushing out PS, (iii) A method is provided for foaming PS using any one of the foaming agents of the present invention, each of which contains foaming agent 1 to foaming agent 6, wherein the foam has a density of about 31 kg / m3 or less and a thermal conductivity over time of 30 mW / mk or less. For convenience, the method according to this paragraph will be referred to as Method 6F in this specification.

[0128] The present invention also provides a method for producing a thermoplastic foam comprising each of Methods 1 to 6, wherein the foaming agent is used in an amount of about 4 parts (hereinafter, "pph" or "pphr") to about 10 pphr per 100 parts of thermoplastic resin material. For convenience, the method according to this paragraph will be referred to as Method 7.

[0129] The present invention also provides a method for producing a thermoplastic foam comprising each of Methods 1 to 6, wherein the blowing agent is used in an amount of about 5 pphr to about 9 pphr. For convenience, the method according to this paragraph will be referred to as Method 8A.

[0130] The present invention also provides a method for producing thermoplastic foams, comprising each of Methods 1 to 6. The present invention provides a method in which the foaming agent is used in an amount of 5 pphr to 9 pphr. For convenience, the method according to this paragraph will be referred to as Method 8A.

[0131] The present invention also provides a method for producing a thermoplastic foam comprising each of Methods 1 to 6, wherein the blowing agent is used in an amount of about 6 pphr to about 8 pphr. For convenience, the method according to this paragraph will be referred to as Method 9A.

[0132] The present invention also provides a method for producing a thermoplastic foam comprising each of Methods 1 to 6, wherein the blowing agent is used in an amount of 6 pphr to 8 pphr. For convenience, the method according to this paragraph will be referred to as Method 9B.

[0133] The present invention also provides a method for producing a thermoplastic foam comprising each of Methods 1 to 6, wherein the blowing agent is used in an amount starting from about 6.5 pph. For convenience, the method according to this paragraph will be referred to as Method 10A.

[0134] The present invention also provides a method for producing a thermoplastic foam comprising each of Methods 1 to 6, wherein the blowing agent is used in an amount starting from about 7 pph. For convenience, the method according to this paragraph will be referred to as Method 10B.

[0135] The present invention also provides a method for producing a thermoplastic foam comprising each of Methods 1 to 10, wherein the step of providing the thermoplastic material or PS comprises the step of incorporating one or more optional components selected from surfactants, polymer modifiers, reinforcing agents, colorants, dyes, solubility enhancers, rheology modifiers, plasticizers, combustion inhibitors, antimicrobial agents, viscosity-reducing modifiers, fillers, vapor pressure modifiers, nucleating agents, catalysts, and the like into the thermoplastic material. For convenience, the method according to this paragraph will be referred to as Method 11.

[0136] The present invention comprises each of methods 1 to 10, which can be formed from any PS resin containing a general-purpose styrene resin having preferably an MVR of 0.1 to 50 g / 10 min, more preferably 10 to 40 g / 10 min, and more preferably 10 to 30 g / 10 min.

[0137] This method may be carried out, for example, using a general type of extruder disclosed in Figure 1, which will be described in more detail below in relation to the examples. Although Figure 1 shows only a single supply point for introducing the blowing agent into the extrusion process, it will be understood that the use of multiple supply points for introducing the blowing agent may also be used. Furthermore, it will be understood that the term “blowing agent” as used herein, including each of blowing agents 1 to 4, includes not only a defined set of components introduced into the extruder when there is a single supply point, but also a collective combination of components that can be introduced into the extruder or other blowing device at multiple points. [Examples]

[0138] The following embodiments are provided for illustrative purposes only, and are not intended to limit the scope of the present invention.

[0139] In the embodiments, substantially the extrusion apparatus shown in Figure 1 was used. Specifically, this apparatus included a raw material supply hopper 10 for holding the polystyrene feed material 15, along with any of the components (which may be added together with the polystyrene or, optionally, elsewhere in the process, depending on the specific needs of the user). In the embodiments herein, the polystyrene feed material is sold by Ineos under the trade name Styrolution 156F and is in the form of general-purpose polystyrene pellets having the following characteristics:

[0140] [Table 2]

[0141] The supplied materials also contained a flame retardant, a nucleating agent (GRANIC2281), and a processing aid (zinc stearate), which are sold under the trade name Apryos 5PB12HT. The total raw material feed stream 15 used to form the foam and introduced into the single-screw extruder 20 is based on the following component concentrations:

[0142] [Table 3]

[0143] The supply material 15, excluding the foaming agent, was loaded into a hopper and supplied to the screw extruder 10 at a nominal speed of approximately 3.3 kilograms / hour, and the screw was operated at a nominal speed of 85 rpm. The extruder 20 had thermocouples (not shown) located at three points along its length and a pressure sensor (not shown) at the discharge end 20A of the extruder. The mixer section 30 was located at the discharge end 20A of the extruder to receive the foaming agent components via one or more metering pumps 40A and 40B and mix these foaming agents into the polystyrene molten material in the mixer section. Sensors (not shown) were included to monitor the temperature and pressure of the mixer section 30. The mixer section 30 discharged the molten material containing the foaming agent into a pair of molten coolers 50 oriented in series, with temperature sensors (not shown) located in each cooler to monitor the molten material temperature. The molten material was then extruded through a die 60, which also had temperature sensors and pressure sensors (not shown) to monitor the pressure and temperature at the die. The die pressure was varied between 70 and 100 bar to minimize the density of each foaming agent, and the die temperature was maintained at 128°C. The foamed polystyrene sheets 70 were discharged from the extruder by a conveyor belt 80 and exited the die.

[0144] The apparatus shown in Figure 1 and described above was used in each of the experimental tests described in the following examples to form the foam. After the foam was formed, the density and thermal conductivity over time (also called "lambda over time") were measured. The lambda over time values ​​were measured according to ISO 11561:199 (which provides results similar to the European standard BS EN 13164:2012+A1:2015) and modified as described below.

[0145] Day 0 - Push out the foam.

[0146] Day 1 - Determine the initial thermal conductivity of the block (skin, 120 x 120 mm, thickness 15-20 mm) at 10°C ± 2°C.

[0147] Day 4 - The block is sliced ​​into 6mm thick slices (skin removed) to obtain one slice per extruded sample measuring 23mm wide and 120mm long, and then at least four slices are stacked. The thermal conductivity of the stack is measured at 10°C + / - 2°C, then the slices are separated and kept at approximately 23°C and 50% relative humidity.

[0148] Method A is used to obtain the thermal conductivity over time, which involves repeating the procedure on day 4 every 2 or 3 days until approximately day 28, plotting the lambda value against time, and then calculating the thermal conductivity over time (time λ).

[0149] Comparative Example 1: XPS foam from a blowing agent consisting of 1234ze(E) and methyl formate

[0150] As described above, extruded polystyrene foam was produced using the apparatus and materials shown in Figure 1. Approximately 6.5 pphr of the blowing agent (referred to as BA-C1A in the table below) produced foam with the density and lambda over time reported in Table C1A below.

[0151] [Table 4]

[0152] As can be seen from the results above, this combination of components produced a foam with a desirable lambda over time of less than 30, but with an undesirable density much greater than the desirable density of 32 or less. In an attempt to produce a foam with reduced density by modifying the blowing agent, a second foam extrusion was performed using the same apparatus, operating criteria, and raw materials as described above in relation to Comparative Example C1A, except that 0.75 pphr of CO2 was added to the blowing agent combination. The results for the blend components (identified as BA-C1B in the table below) and the foam are reported in Table C1B below.

[0153] [Table 5]

[0154] As can be seen from the comparative examples above, the addition of CO2 to the foaming agent blend had the expected result of reducing the density of the foam. Specifically, the foam density decreased from 43.5 to 41, which is a decrease of approximately 6 relative percent. However, this reduction was by no means sufficient to result in a concentration of approximately 32 or less. The addition of CO2 also had the expected drawback of increasing the thermal conductivity of the foam. In the particular case of this example, the lambda over time increased by approximately 3%, which is an undesirable result. In the particular case of this example, the lambda over time increased by almost 5%, which is a very undesirable result. This expected adverse effect is shown in Figure 2. Furthermore, the lambda over time is not below 30, as is the most desirable case.

[0155] Comparative Example 2 - XPS foam from a blowing agent consisting of 1233zd(E), 1234ze(E), isobutane, and methyl formate.

[0156] As described above, extruded polystyrene foam was produced using the apparatus and materials shown in Figure 1. Approximately 7.25 pphr of the blowing agent (referred to as BA-C2 in the table below) produced foam with the density and lambda over time reported in Table C2 below.

[0157] [Table 6]

[0158] As can be seen from the results above, this combination of components produced a foam with a desirable time-dependent lambda of less than 30, but with an undesirable density much higher than the desirable density of about 32 or less, although the density was substantially much lower than the density achieved with BA-C1A in Comparative Example 1.

[0159] Example 1 - XPS foam from a blowing agent consisting of 1233zd(E), 1234ze(E), isobutane, methyl formate, and CO2.

[0160] In an attempt to achieve a foam with reduced density by modifying the blowing agent used in Comparative Example C2, a second foam extrusion was performed using the same apparatus, operating criteria, and raw materials as described above in relation to Comparative Example C2, except that 0.75 pphr of CO2 was added to the blowing agent combination. The blend components and foam results are reported in Table E1 below.

[0161] [Table 7]

[0162] As can be seen from the results reported above, the addition of CO2 to the blowing agent blend had the unexpected result of reducing the density of the foam by approximately 11% (from 37.8 to 34), which is about twice the reduction achieved by using the same amount of CO2 in relation to the blowing agent blend in comparative example C1 (a reduction of 6.1%, from 43.5 to 41). This unexpected result is very significant because it is highly desirable for the foam to have a density of approximately 34 or less for various commercial applications. Furthermore, the addition of CO2 also had the unexpected benefit of significantly reducing the thermal conductivity of the foam. This, combined with the unexpectedly low lambda over time achieved without CO2, results in a very desirable unexpected outcome, which is shown in Figure 3.

[0163] Comparative Example: XPS foam from a blowing agent consisting of C3-trans-HFO-1234ZE, isobutane, and methyl formate.

[0164] As described above, extruded polystyrene foam was produced using the apparatus and materials shown in Figure 1. Approximately 6.5 pphr of the blowing agent (referred to as BA-C3 in the table below) produced a foam with the indicated density and lambda over time.

[0165] [Table 8]

[0166] As can be seen from the comparative examples above, the combination of 1234ze(E), isobutane, and methyl formate in relative amounts, while still not below 31, was able to achieve a relatively low lambda value over time. In terms of density, the foam had an undesirably high density of 38.

[0167] Comparative Example: XPS foam from a blowing agent consisting of C4-trans-HFO-1234ZE, isobutane, and acetone.

[0168] Except for using a 7 pph blowing agent consisting of the components shown in Table C4 below, a foam extrusion run was performed using the same apparatus, operating criteria, and raw materials as described above in relation to Comparative Example 3 to produce a foam having the indicated density and lambda over time.

[0169] [Table 9]

[0170] As can be seen from the comparative examples above, the combination of 1234 ze(E), isobutane, and acetone in relative amounts produced a foam with an even higher lambda value over time than comparative example C3, but with a slightly reduced density of 36.3. Therefore, the use of this blowing agent could not provide a polystyrene foam with a density of less than 35 kg / m3 and a thermal conductivity of less than 31 mW / mk at the same time.

[0171] Example 2 - XPS foam from a blowing agent consisting of trans-HFO-1234ZE, isobutane, methyl formate, and CO2

[0172] Except for using a 7 pph blowing agent consisting of the components shown in Table E2 below, foam extrusion runs were performed using the same apparatus, operating criteria, and raw materials as described above in relation to Comparative Examples C3 and C4 to produce foams with the indicated density and lambda over time.

[0173] [Table 10]

[0174] As can be seen from the above examples, surprising and highly beneficial results can be achieved using blowing agents within the scope of the present invention. Specifically, as described above in relation to comparative examples C2 and C3, neither the combination of 1234ze(E), isobutane, and methyl formate nor the combination of 1234ze(E), isobutane, and acetone could achieve a lambda value over time of less than 31 or a foam density of about 36. While the addition of CO2 as a co-blowing agent blend in comparative example C2 is expected to cause an increase in the lambda of the foam over time, the applicants have surprisingly found that the use of relatively small amounts of CO2 in combination with 1234ze(E), isobutane, and methyl formate can result not only in the expected decrease in foam density, but also, unexpectedly, in a substantial reduction in lambda over time from a value of less than 31.3 to a value of less than 30, which was not achieved by any of the comparative examples.

[0175] However, unexpectedly, the blowing agent according to the present invention, comprising 1234ze(E), isobutane, methyl formate, and CO2, was remarkably able to produce a foam density of less than 36.6 and a time-dependent lambda value of less than 30, which were not achieved by any of the comparative examples. This result is remarkable and highly beneficial, and is shown in Figure 4.

[0176] Comparative Example C5-1234ze(E) and XPS foam prepared using dimethyl ether (DME) and methyl formate.

[0177] Extruded polystyrene foam was produced using the apparatus and materials shown in Figure 1, as described above. The blowing agent (referred to as BA-C5 in the table below) was a combination of 1234ze(E), DME, and methyl formate. The blowing agent was added to the molten material at a volume of 6.25 pphr (wherein used herein, "pphr" means parts per 100 parts of polymer resin by weight). The die pressure that minimized the foam density was determined and used to produce the foam. The results are reported in C5 below.

[0178] [Table 11]

[0179] As can be seen from the comparative examples above, the combination of the indicated amounts of 1234ze(E), DME, and methyl formate produced a foam with an undesirably high density of 38.1 and a relatively low lambda value over time, but it still did not fall below the most preferable value of 31 or less.

[0180] Example 3 - XPS foam from a blowing agent consisting of trans-HFO-1234ZE, DME, methyl formate, and CO2

[0181] Except for adding 0.25g of CO2 to the blowing agent (relative to a total blowing agent volume of 6.5 pphr), the foam extrusion process was performed using the same apparatus, operating criteria, and raw materials as described above in relation to Comparative Example C5. The blowing agent (referred to as BA-E3 in the table below) produced a foam with the indicated density and lambda over time.

[0182] [Table 12]

[0183] As can be seen from the above examples, surprising and highly beneficial results can be achieved using blowing agents within the scope of the present invention. Specifically, as described above in relation to Comparative Example 5, the combination of 1234ze(E), DME, and methyl formate could not achieve a time-dependent lambda value of less than 31 or a foam density of less than 38.1. Although the addition of CO2 as a co-blowing agent is expected to cause an increase in the foam's time-dependent lambda, the applicants have surprisingly found that the use of relatively small amounts of CO2 in combination with 1234ze(E), DME, and methyl formate can produce a foam density of less than 35 and a time-dependent lambda value of less than 31, which were not achieved by any of the comparative examples, as shown in Figure 5.

[0184] XPS foam from a blowing agent consisting of trans-HFCO-1233ZD, isobutane and methyl formate in Comparative Example C6

[0185] Except for using a 6.5 pph blowing agent consisting of the components shown in Table C6 below, the same apparatus, the same operating criteria, and the same raw materials as those described above in relation to Comparative Examples C1 - C5 were used to perform a foam extrusion run to produce a foam having the indicated density and lambda over time.

[0186] [Table 13]

[0187] As can be seen from the above comparative examples, the combination of the indicated relative amounts of 1233zd(E), isobutane and methyl formate was still not less than 31, but was able to achieve a relatively low lambda value over time, although it produced a foam having an undesirably high density of approximately 35.

[0188] XPS foam from a blowing agent consisting of trans-HFCO-1233ZD, isobutane, methyl formate and CO2 in Example

[0189] Except for using a 6.5 pph blowing agent consisting of the components shown in Table E4 below, the same apparatus, the same operating criteria, and the same raw materials as those described above in relation to Comparative Example C6 were used to perform a foam extrusion run to produce a foam having the indicated density and lambda over time.

[0190] [Table 14]

[0191] As can be seen from the above examples, by using a blowing agent within the scope of the present invention, surprisingly very beneficial results are achieved. Specifically, as described above in relation to Comparative Example C6, the combination of 1233zd(E), isobutane and methyl formate was unable to achieve a foam density of less than 34. The addition of CO2 as a co-blowing agent blend in Comparative Example C6 was expected to cause a substantial increase in the lambda of the foam over time. However, the applicants have surprisingly found that the use of a relatively small amount of CO2 in combination with 1233zd(E), isobutane and methyl formate can not only result in a predicted reduction in the foam density to a value close to 32, but unexpectedly, this enhancement of the density is achieved without a substantial reduction in lambda over time. This result is surprising and very beneficial.

[0192] Comparative Example 7 - XPS foam from a blowing agent containing 1234ze(E), 1233zd(E) and isobutane

[0193] Except for using a blowing agent of 7.5 pph consisting of the components shown in Table C6 below, foam extrusion runs were performed using the same equipment, the same operating criteria, and the same raw materials as described above in relation to Comparative Examples C1 - C6 to produce foams having the indicated densities and lambda over time.

[0194]

Table 15

[0195] As can be seen from the above comparative examples, this combination of components in the indicated relative amounts produced foams with an undesirably high density above 35, although the density produced had a desirable value of 28.7.

[0196] Comparative Example 8 - XPS foam from a blowing agent consisting of 1234ze(E), 1233zd(E), isobutane, and ethanol

[0197] As shown in Table C8 below, foam extrusion was performed using the same apparatus, operating criteria, and raw materials as described above in relation to the experiment reported in Table C7 of Comparative Example 7, except that ethanol at 0.5 and 0.75 pph was added as a co-foaming agent (to produce foaming agents referred to as BA-C8A and BA-C8B) to produce foams (referred to as C8 foam 1 and C8 foam 2) having the indicated density and lambda over time.

[0198] [Table 16]

[0199] As can be seen from the comparative examples above, the addition of ethanol as a co-foaming agent in the relative amounts shown produced foam without substantially reducing the density to a value far below the highly undesirable density of about 35. However, the applicants noted that the addition of ethanol to these blends has the desirable result of substantially reducing the thermal conductivity of the foam over time.

[0200] Examples 5A and 5B: XPS foam from a blowing agent consisting of trans-HFO=1234ZE, trans-HFCO-1233ZD, isobutane, ethanol, and CO2

[0201] As reported in Table E5 below, a foam extrusion run was performed using the same apparatus, operating criteria, and raw materials as described above in relation to Comparative Example 8, except that CO2 was added as a co-foaming agent at two different concentrations (identified as BA-E5A and BA-E5B), producing two foams (identified as foam E5A and foam E5B) with the indicated densities and lambda over time.

[0202] [Table 17]

[0203] As can be seen from the above examples, surprising and highly beneficial results can be achieved using blowing agents within the scope of the present invention. Specifically, as described above in relation to Comparative Example C8, the combination of 1234ZE(e), 1233zd(E), ethanol, and isobutane could not achieve a foam density of less than 34. While the addition of CO2 as a co-blowing agent blend in Comparative Example C8 is expected to cause a substantial increase in the lambda over time of the foam, the applicants have surprisingly found that the use of relatively small amounts of CO2 in combination with 1234ZE(e), 1233zd(E), ethanol, and isobutane can not only result in the expected reduction of the foam density to a value close to or less than 32, but unexpectedly, this reduction in density is achieved without a substantial reduction in the lambda over time. This result is surprising and highly beneficial, as shown in Figures 6A and 6B.

Claims

1. A blowing agent for producing an extruded polystyrene foam having low lambda over time and low foam density, wherein the blowing agent is (a) Approximately 50% to approximately 70% by weight of one or more HFOs having three or four carbon atoms and / or HFCOs having three or four carbon atoms, (b) A first co-foaming agent consisting essentially of methyl formate, ethanol, and combinations thereof in an amount of approximately 5% to 20% by weight, (c) A second co-foaming agent consisting of approximately 20% to 40% by weight of dimethyl ether, isobutane, and combinations thereof, (d) A blowing agent comprising a third co-blowing agent essentially consisting of about 2% to 5% by weight of carbon dioxide.

2. The blowing agent according to claim 1, wherein the sum of (a), (b), (c), and (d) constitutes at least about 90% by weight of the blowing agent, and optionally the sum of (a), (b), (c), and (d) constitutes at least about 95% by weight of the blowing agent.

3. The blowing agent according to claim 2, wherein the sum of (a), (b), (c), and (d) constitutes at least about 97% by weight of the blowing agent.

4. The aforementioned foaming agent, (a) Approximately 50% to approximately 65% ​​by weight of one or more HFOs having three or four carbon atoms and / or HFCOs having three or four carbon atoms, (b) A first co-foaming agent consisting essentially of methyl formate, ethanol, and combinations thereof in an amount of approximately 5% to 15% by weight, (c) A second co-foaming agent consisting of approximately 20% to 35% by weight of dimethyl ether, isobutane, and combinations thereof, (d) The blowing agent according to claim 1, comprising a third co-blowing agent essentially consisting of less than about 5% by weight of carbon dioxide.

5. The aforementioned foaming agent, (a) 1234ze(E) in an amount of approximately 55% to 65% by weight, (b) A first co-foaming agent consisting essentially of about 5% to about 15% by weight of methyl formate, (c) A second co-foaming agent consisting of approximately 20% to 25% by weight of dimethyl ether, isobutane, and combinations thereof, (d) The blowing agent according to claim 1, comprising a third co-blowing agent essentially consisting of about 3% to about 5% by weight of carbon dioxide.

6. The aforementioned foaming agent, (a) Approximately 50% to 60% by weight of 1234ze(E), 1233zd(E), and combinations thereof, (b) A first co-foaming agent consisting essentially of about 5% to about 15% by weight of ethanol, (c) A second co-foaming agent consisting essentially of approximately 25% to 40% by weight of isobutane, (d) The blowing agent according to claim 1, comprising a third co-blowing agent essentially consisting of about 3% to about 5% by weight of carbon dioxide.

7. The aforementioned foaming agent, (a) Approximately 50% to 60% by weight of 1234ze(E), 1233zd(E), and combinations thereof, (b) A first co-foaming agent consisting essentially of about 5% to about 15% by weight of ethanol, (c) A second co-foaming agent consisting essentially of approximately 25% to 35% by weight of isobutane and combinations thereof, (d) The blowing agent according to claim 13, comprising a third co-blowing agent essentially consisting of about 3% to about 5% by weight of carbon dioxide.

8. A blowing agent for producing an extruded polystyrene foam having low lambda over time and low foam density, wherein the blowing agent is (a) A combination of 1234ze(E) and 1233zd(E) in an amount of approximately 45% to 65% by weight, (b) A first co-foaming agent consisting essentially of methyl formate, ethanol, or a combination thereof in an amount of approximately 5% to 15% by weight, (c) A second co-foaming agent consisting essentially of approximately 25% to 40% by weight of isobutane, (d) A blowing agent comprising a third co-blowing agent essentially consisting of about 3% to 5% by weight of carbon dioxide.

9. A blowing agent for producing an extruded polystyrene foam having low lambda over time and low foam density, wherein the blowing agent is (a) 1233zd(E) in an amount of approximately 45% to 65% by weight, (b) Approximately 5% to 15% by weight of methyl formate, (c) Approximately 15% to 35% by weight of isobutane, (d) A blowing agent containing approximately 3% to 5% by weight of carbon dioxide.

10. A blowing agent for producing an extruded polystyrene foam having low lambda over time and low foam density, wherein the blowing agent is (a) 1234ze(E) in an amount of approximately 45% to 65% by weight, (b) Approximately 5% to 15% by weight of methyl formate, (c) Approximately 15% to 35% by weight of isobutane, (d) A blowing agent containing approximately 3% to 5% by weight of carbon dioxide.

Images