JP2023067491A - Method for manufacturing thermoplastic resin extrusion foam plate - Google Patents

Abstract

To provide a method for manufacturing a thermoplastic resin extrusion foam plate which enables stable manufacture of a thermoplastic resin extrusion foam plate having low long-term heat conductivity, and is also excellent in moldability.SOLUTION: A method for manufacturing an extrusion foam plate extrudes and foams a foamable resin composition obtained by kneading a base material resin, a physical foaming agent and a flame retardant, and forms the foamable resin composition in a plate shape by a molding tool, wherein the base material resin contains a styrene-(meth)acrylate copolymer as a main component, a percentage content of the (meth)acrylate component in the base material resin is 25 mass% or more and 90 mass% or less, the total blending amount of the physical foaming agent is within a specific range, the physical foaming agent contains hydrofluoroolefin, and the total blending amount of the hydrofluoroolefin is within a specific range.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a method for producing an extruded thermoplastic resin foam board, and more particularly to a method for producing an extruded thermoplastic resin foam board having excellent moldability and production stability in extrusion foam molding and low long-term thermal conductivity.

Conventionally, a foam control agent is added to a polystyrene resin, heated and kneaded in an extruder, then a physical foaming agent is injected into the extruder and further kneaded, and the resulting molten mixture is transferred from a high pressure range to a low pressure range (usually in the atmosphere). A known method is to obtain a thick polystyrene-based resin extruded foam board by extruding the resin into the middle) and shaping it into a board using a shaping device connected to the die outlet of the extruder.

The extruded foam board obtained by this method has low thermal conductivity and excellent heat insulating properties, and is therefore suitable for use as a heat insulating material for walls, floors, roofs, etc. of buildings.
However, the conventional extruded foam board uses polystyrene resin as the main component of the base resin and uses a mixture of isobutane and hydrofluoroolefin (hereinafter also referred to as HFO) as the physical foaming agent. There is still room for improvement in terms of improving heat insulation by reducing the size.

That is, the thermal conductivity of the extruded foam board is affected by the thermal conductivity of the thermoplastic resin and the thermal conductivity of the residual physical foaming agent, and is particularly strongly affected by the thermal conductivity of the residual physical foaming agent. Therefore, if the thermal conductivity of the physical foaming agent itself is low, an extruded foam board with low thermal conductivity immediately after production can be obtained. However, when the permeability coefficient of the physical foaming agent to the cell membrane is large, the amount of the physical foaming agent remaining in the cells decreases over time, and at the same time, air with high thermal conductivity penetrates into the cells. thermal conductivity tends to increase.

From this point of view, isobutane has a lower thermal conductivity than air, but has a large permeability coefficient with respect to a foam membrane made of polystyrene resin, so there is room for improvement in terms of keeping the thermal conductivity low for a long period of time. There is In order to obtain an extruded foam board with excellent long-term thermal conductivity (long-term thermal conductivity), it is necessary to use a physical material that has a lower thermal conductivity than air, a small gas permeability coefficient, and a low thermal conductivity over a long period of time. It is preferred to use a blowing agent. Physical blowing agents that meet this requirement include hydrofluoroolefins (HFOs).

However, in the prior art, when a polystyrene resin is used as a base resin and a hydrofluoroolefin is used as a physical blowing agent, the foamability of the molten mixture containing the polystyrene resin and the physical blowing agent is reduced. It has been desired to be able to more stably produce good extruded foam boards.

On the other hand, attempts have been made to use a mixed resin of a polystyrene resin and a styrene-(meth)acrylic acid ester copolymer for the production of extruded foam boards (eg, Patent Document 1). Furthermore, it is known that the permeability coefficient of the physical blowing agent to the styrene-(meth)acrylic acid ester copolymer is much smaller than the permeability coefficient of the physical blowing agent to the polystyrene resin. Therefore, by using a styrene-(meth)acrylic acid ester copolymer instead of a polystyrene resin, or by using a polystyrene-based resin and a styrene-(meth)acrylic acid ester copolymer together, it is possible to maintain heat over a long period of time. It is expected that an extruded foam board with low conductivity can be obtained. The styrene-(meth)acrylic acid ester copolymer has a smaller air permeability coefficient than polystyrene resin, so it suppresses the increase in thermal conductivity caused by air entering the foamed extruded board. It is also expected that

JP 2008-133424 A

However, in the past, no attempts have been made to use a styrene-(meth)acrylic acid ester copolymer as the main component of the base resin and combine it with a hydrofluoroolefin (HFO). For example, in Patent Document 1, although a base resin made of a polystyrene resin and a styrene-(meth)acrylic acid ester copolymer is used, the physical foaming agent is a mixed foaming of isobutane and methyl chloride. Only agents are disclosed.

Furthermore, in the prior art, resins mainly composed of styrene-(meth)acrylic acid ester copolymers are inferior in foamability when physical foaming agents such as butane are used. There is room for further improvement in order to stably obtain it.

INDUSTRIAL APPLICABILITY The present invention can stably produce a thermoplastic resin extruded foam board having a small long-term thermal conductivity, is excellent in moldability (hereinafter simply referred to as moldability) at the time of extrusion foaming, and can be easily formed into a plate. It is an object of the present invention to provide a method for producing a thermoplastic resin extruded foam board that can obtain a foam of

According to the present invention, there is provided a method for producing a thermoplastic resin extruded foam board as described below.
[1] A method for producing an extruded thermoplastic resin foam board, which includes a step of extruding and foaming a foamable resin composition obtained by kneading a base resin, a physical foaming agent, and a flame retardant, and molding the foamed board into a board using a molding tool. can be,
The base resin is mainly composed of a styrene-(meth)acrylic acid ester copolymer,
The content of the (meth)acrylic acid ester component derived from the styrene-(meth)acrylic acid ester copolymer in the base resin is 25% by mass or more and 90% by mass or less,
The total amount of the physical foaming agent compounded is 0.8 mol or more and 1.3 mol or less per 1 kg of the base resin,
A thermoplastic resin extruded foam board characterized in that the physical foaming agent contains a hydrofluoroolefin, and the total amount of the hydrofluoroolefin compounded is 0.5 mol or more and 1.3 mol or less per 1 kg of the base resin. Production method.
[2] The content of the (meth)acrylic acid ester component derived from the styrene-(meth)acrylic acid ester copolymer in the base resin is 50% by mass or more and 80% by mass or less. 2. The method for producing a thermoplastic resin extruded foam board according to 1.
[3] The method for producing a thermoplastic resin foam board as described in [1] or [2] above, wherein the styrene-(meth)acrylate copolymer is a styrene-methyl methacrylate copolymer.
[4] The thermoplastic resin according to any one of [1] to [3] above, wherein the total amount of the hydrofluoroolefin compounded is 0.5 mol or more and 1.0 mol or less per 1 kg of the base resin. A method for manufacturing a foam board.
[5] the hydrofluoroolefin comprises 1-chloro-3,3,3-trifluoropropene (HFO-1233zd) and/or 1,3,3,3-tetrafluoropropene (HFO-1234ze);
The total amount of 1-chloro-3,3,3-trifluoropropene (HFO-1233zd) and/or 1,3,3,3-tetrafluoropropene (HFO-1234ze) compounded per 1 kg of the base resin 5. The method for producing a thermoplastic resin foam board according to any one of 1 to 4 above, wherein
[6] The hydrofluoroolefin contains 1,3,3,3-tetrafluoropropene (HFO-1234ze), and the content of the 1,3,3,3-tetrafluoropropene (HFO-1234ze) is 5. The method for producing a thermoplastic resin foam board according to any one of 1 to 4 above, wherein the content is 0.5 mol or more per 1 kg of the material resin.
[7] The content (X) [% by mass] of the (meth)acrylic acid ester component derived from the styrene-(meth)acrylic acid ester copolymer in the base resin, and 1,3,3,3- 6. The method for producing a thermoplastic resin foam board according to 6 above, wherein the compounding amount (Y) of tetrafluoropropene (HFO-1234ze) [mol/1 kg of base resin] satisfies the following formula (1): .
Y<0.024X−0.4 (1)

INDUSTRIAL APPLICABILITY The present invention has excellent moldability and is easy to form into a plate shape, and can easily and stably produce a thermoplastic resin extruded foam plate. It can maintain excellent heat insulating properties over a period of time.

In the method for producing an extruded thermoplastic resin foam board of the present invention, a step of extruding and foaming an expandable resin composition obtained by kneading a base resin, a physical foaming agent and a flame retardant to form a plate with a molding tool. A thermoplastic resin extruded foam board (hereinafter also referred to as an extruded foam board) is manufactured by a method including. Specifically, for example, additives such as a flame retardant and a cell control agent are added to the base resin, supplied to an extruder, heated and kneaded, and then a physical foaming agent is injected into the extruder and further kneaded. to form a foamable resin composition, the foamable resin composition is extruded from a high pressure region to a low pressure region (usually in the atmosphere) to foam, and the resulting foam is a shaper connected to the die outlet of the extruder A thermoplastic resin extruded foam board is produced by shaping into a board using a device (guider, etc.). As the shaping device, for example, a device composed of a pair of upper and lower polytetrafluoroethylene plates is used.

In the present invention, the base resin is mainly composed of a styrene-(meth)acrylic acid ester copolymer. The styrene-(meth)acrylic acid ester copolymer has a lower permeability coefficient to hydrofluoroolefin (HFO) and a lower permeability coefficient to air than polystyrene resins conventionally used for manufacturing extruded foam boards. Therefore, it is a preferable resin in that an extruded foam board having excellent long-term heat insulation properties can be obtained.

The styrene-(meth)acrylic acid ester copolymer is a copolymer of styrene and a (meth)acrylic acid lower alkyl ester. Specifically, examples thereof include styrene-methyl acrylate copolymer, styrene- Examples include ethyl acrylate copolymer, styrene-propyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-propyl methacrylate copolymer and the like. Among these copolymers, styrene-methyl acrylate copolymers and styrene-methyl methacrylate copolymers are preferred, and styrene-methyl methacrylate copolymers are more preferred. These styrene-(meth)acrylic acid ester copolymers can be used singly or in combination of two or more. In this specification, "(meth)acrylic acid" is a concept including "acrylic acid" and "methacrylic acid", and means one or both of them.

In this specification, the base resin mainly composed of a styrene-(meth)acrylic acid ester copolymer means that the content of the styrene-(meth)acrylic acid ester copolymer in the base resin is 50 mass. % or more, preferably 60 mass % or more, more preferably 70 mass % or more, still more preferably 90 mass % or more, including 100 mass %. The larger the content, the smaller the gas permeability coefficient of the physical foaming agent and air with respect to the base resin, which is preferable.

Furthermore, in the base resin, the content of the (meth)acrylic acid ester component derived from the styrene-(meth)acrylic acid ester copolymer is 25% by mass or more and 90% by mass or less. This configuration has a strong relationship with the use of a hydrofluoroolefin (HFO), which will be described later, as a physical blowing agent, and the base resin containing the (meth)acrylic acid ester component with a high content rate is combined with HFO. The present invention is characterized by the use of That is, when the HFO is used as a physical foaming agent, even when the content of the (meth)acrylic acid ester component is high, it is possible to obtain a good extruded foam board with excellent foamability and moldability. From this point of view, the content is preferably 30% by mass or more and 85% by mass or less, more preferably 40% by mass or more and 80% by mass or less, and still more preferably 50% by mass or more and 80% by mass or less.

In the present invention, as the styrene-(meth)acrylic acid ester copolymer, two or more kinds having different contents of the (meth)acrylic acid ester component can be used in combination. In that case, the total content of (meth)acrylic acid ester components contained in each styrene-(meth)acrylic acid ester copolymer is the (meth)acrylic acid ester component of the styrene-(meth)acrylic acid ester copolymer. The content rate of

If the content of the (meth)acrylic acid ester component in the base resin is too low, the heat conductivity of the extruded foam board is prevented from increasing by preventing the dissipation of the hydrofluoroolefin described later. The rate retention effect (effect of preventing deterioration of heat insulating properties) becomes smaller. In addition, the HFO is likely to separate from the foam board, gas spots occur frequently, and the appearance of the surface of the extruded foam board may deteriorate. On the other hand, if the content of the (meth)acrylic acid ester component is too high, the effect of maintaining a low thermal conductivity can be obtained, but the formability may deteriorate, making it impossible to obtain an extruded foam board. Moreover, the flame retardance deteriorates, and there is a possibility that the flame retardance standard required for building materials cannot be satisfied. However, the flame retardancy is also affected by the type and amount of flame retardant used in production, the density of the extruded foam, the type of foaming agent in the extruded foam, and the amount remaining.

The effect of maintaining low thermal conductivity by the styrene-(meth)acrylic acid ester copolymer is that the (meth)acrylic acid ester component suppresses the dissipation of HFO, which has low thermal conductivity, from the extruded foam board and has high thermal conductivity. It is expressed by simultaneously suppressing the inflow of air into the extruded foam board. Therefore, when the (meth)acrylic acid ester component in the styrene-(meth)acrylic acid ester copolymer decreases, HFO tends to dissipate from the extruded foam board, and the thermal conductivity of the extruded foam board tends to increase. . However, when an extruded foam is produced using only a styrene-(meth)acrylic acid ester copolymer having an excessively large amount of (meth)acrylic acid ester component, as described above, the moldability deteriorates, It becomes difficult to satisfy flame retardant standards.

Therefore, when using a styrene-(meth)acrylic acid ester copolymer with a large amount of (meth)acrylic acid ester, use a styrene-(meth)acrylic acid ester copolymer with a low (meth)acrylic acid ester component. It is preferable to use them together and set the content of the (meth)acrylic acid ester component in the range described above.

When a styrene-(meth)acrylic ester copolymer with a large (meth)acrylic ester component and a styrene-(meth)acrylic ester copolymer with a low (meth)acrylic ester component are used in combination, the component As the styrene-(meth)acrylic acid ester copolymer with a large amount, the component in the styrene-(meth)acrylic acid ester copolymer is preferably 50% by mass or more and 85% by mass or less, and 60% by mass or more. It is more preferably 80% by mass or less. As the styrene-(meth)acrylic acid ester copolymer with a small amount of the component, the content of the component in the styrene-(meth)acrylic acid ester copolymer is preferably 10% by mass or more and less than 50% by mass, and is 15% by mass. % or more and 30 mass % or less.

The content of the (meth)acrylic acid ester component in the styrene-(meth)acrylic acid ester copolymer can be determined by a known method such as pyrolysis gas chromatographic analysis.

Further, in the present invention, other polymers such as polystyrene resins, polyester resins, polyolefin resins, styrene elastomers and polyphenylene ether resins may be blended into the base resin within a range that does not hinder the object of the present invention. It can also be used by mixing according to the The amount of such other polymer used is preferably 30% by mass or less, more preferably 20% by mass or less, in the base resin (based on the total base resin being 100% by mass). It is more preferably 10% by mass or less, and particularly preferably 5% by mass or less. The term "polystyrene resin" as used herein refers to a polystyrene resin that does not contain a (meth)acrylic acid ester component.

Physical blowing agents used in the method of the present invention include hydrofluoroolefins (HFO). The HFOs have zero or very low ozone depletion potential, low global warming potential, and are non-flammable. Furthermore, since HFO has a low thermal conductivity in the gaseous state, it can lower the thermal conductivity of the extruded foam insulation board.

The physical blowing agent used in the method of the present invention includes hydrocarbons having 1 to 5 carbon atoms such as isobutane, aliphatic alcohols having 1 to 5 carbon atoms such as ethyl alcohol, water , a dialkyl ether having an alkyl chain of 1 to 3 carbon atoms, carbon dioxide, and the like can be used in combination.

The total amount of the physical foaming agents to be mixed is 0.8 mol or more and 1.3 mol or less per 1 kg of the base resin. If the total amount is within this range, an extruded foam board having a desired apparent density can be obtained. If the total amount is too small, an extruded foam board having a desired apparent density cannot be obtained. If the total amount is too large, the foaming agent tends to separate from the foaming plate, and gas spots may occur frequently. For this reason, the total amount is preferably 0.9 mol or more and 1.2 mol or less.

The total amount of the HFO compounded is 0.5 mol or more and 1.3 mol or less per 1 kg of the base resin. If the total amount is too small, it may not be possible to obtain an extruded foam board with low thermal conductivity over a desired long period of time. For this reason, the total compounding amount is preferably 0.7 mol or more, more preferably 0.8 mol or more, and still more preferably 0.9 mol or more. If the total amount is too large, the HFO is likely to separate from the foam board, which may result in frequent occurrence of gas spots and deterioration in production stability. For this reason, the total amount is preferably 1.2 mol or less, more preferably 1.1 mol or less, and even more preferably 1 mol or less.

Specific examples of the HFO include 1-chloro-3,3,3-trifluoropropene (hereinafter also referred to as HFO-1233zd), 1,3,3,3-tetrafluoropropene (hereinafter referred to as HFO-1234ze ), 1-chloro-2,3,3,3-terorafluoropropene (hereinafter also referred to as HFO-1224yd), 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,1, 1,4,4,4-hexafluoro-2-butene (HFO-1336mzz) and the like. These foaming agents can be used alone or in combination of two or more.

Among these hydrofluoroolefins (HFO), 1-chloro-3,3,3-trifluoropropene ( HFO-1233zd) and/or 1,3,3,3-tetrafluoropropene (HFO-1234ze) are preferably included in the physical blowing agent.

Furthermore, 1,3,3,3-tetrafluoropropene (HFO-1234ze) has a styrene-(meth)acrylic ester Since the coefficient of permeability to the copolymer is small, the thermal conductivity of the extruded foam board can be kept low for a long period of time. On the other hand, 1-chloro-3,3,3-trifluoropropene (HFO-1233zd) is superior in foamability and moldability to 1,3,3,3-tetrafluoropropene (HFO-1234ze). Therefore, the extruded foam board can be stably produced, and the heat conductivity of the extruded foam board immediately after production can be reduced because of its low thermal conductivity.

The total amount of 1-chloro-3,3,3-trifluoropropene (HFO-1233zd) and/or 1,3,3,3-tetrafluoropropene (HFO-1234ze) is per 1 kg of the base resin. is preferably 0.5 mol or more. When the total compounding amount satisfies the above range, the amount of the foaming agent remaining in the extruded foam board after extrusion foaming increases, resulting in an extruded foam board having more excellent long-term heat insulation properties. From this point of view, the total amount of 1-chloro-3,3,3-trifluoropropene (HFO-1233zd) and/or 1,3,3,3-tetrafluoropropene (HFO-1234ze) is It is more preferably 0.7 mol or more per 1 kg of resin, and even more preferably 0.8 mol or more. On the other hand, from the viewpoint of production stability and moldability, 1-chloro-3,3,3-trifluoropropene (HFO-1233zd) and/or 1,3,3,3-tetrafluoropropene (HFO-1234ze) is preferably 1.3 mol, more preferably 1.2 mol, still more preferably 1.1 mol, and particularly preferably 1 mol per 1 kg of the base resin.

Furthermore, when HFO-1234ze and HFO-1233zd are used as the HFO, the molar ratio between HFO1234ze and HFO-1233zd (HFO-1234ze:HFO-1233zd) is 30:70 from the viewpoint of excellent production stability. 90:10 is preferred, 40:60 to 80:20 is more preferred, and 50:50 to 70:30 is even more preferred.

As described above, 1,3,3,3-tetrafluoropropene (HFO-1234ze) has a small gas permeability coefficient, so that the extruded foam board can keep the thermal conductivity low for a long period of time. Therefore, the hydrofluoroolefin (HFO) preferably contains 1,3,3,3-tetrafluoropropene (HFO-1234ze), and the amount thereof is 0.5 mol or more per 1 kg of the base resin. It is preferably 0.7 mol or more, more preferably 0.8 mol or more. When the blending amount of 1,3,3,3-tetrafluoropropene (HFO-1234ze) satisfies the above range, an extruded foam board having excellent long-term heat insulation properties can be obtained. From the viewpoint of production stability and moldability, the upper limit of the amount to be added is preferably 1.3 mol, more preferably 1.2 mol, and still more preferably 1.1 mol per 1 kg of the base resin. Particularly preferably, it is 1 mol.

Furthermore, the content of the (meth)acrylic acid ester component (X) [% by mass] and the amount of 1,3,3,3-tetrafluoropropene (HFO-1234ze) (Y) [mol/base resin 1 kg] preferably satisfies the following formula (2). When the compounding amount (Y) of HFO-1234ze satisfies the range defined by the formula (2), separation of HFO-1234ze from the molten resin is suppressed, gas spots are not generated, and moldability is excellent, and extrusion is possible. It becomes easy to obtain an extruded foam board having a good appearance on the surface of the foam board. For this reason, it is more preferable to satisfy the following formula (1).
Y<0.024X−0.2 (2)
Y<0.024X−0.4 (1)

As described above, the method of the present invention is characterized by the use of a base resin containing a specific range of (meth)acrylic acid ester as a main component, and the hydrofluoroolefin (HFO) as a physical foaming agent. It is to combine with using as a component.

In the past, polystyrene resin was used as the base resin for forming the extruded foam board, and a mixed foaming agent of isobutane and HFO as the main components was used as the physical foaming agent. HFO is used because it is nonflammable, and has a low thermal conductivity among physical blowing agents. However, among physical blowing agents, HFO has low solubility in polystyrene resins and poor foaming properties. Therefore, combined use of isobutane, which has high solubility in polystyrene resins and excellent foaming properties, together with HFO has been studied.

On the other hand, it is known that the gas permeability coefficient of styrene-(meth)acrylic acid ester copolymer is much smaller than that of polystyrene resin. Therefore, if HFO is used as a physical foaming agent, the main component of the base resin is styrene-(meth)acrylic acid ester copolymer, and the blending ratio of polystyrene resin can be reduced, the thermal conductivity can be kept low for a long time. It may be possible to obtain extruded foam boards that sag. However, the foamability of styrene-(meth)acrylic acid ester copolymers is inferior to that of polystyrene resins. For this reason, studies have been conducted on materials having a low content of (meth)acrylic acid ester component derived mainly from styrene-(meth)acrylic acid ester copolymer in the base resin.

Furthermore, conventionally, when a polystyrene resin is used as the base resin and HFO is used as the physical foaming agent, the foamability of the polystyrene resin decreases, making it difficult to obtain a good extruded foam board. Therefore, conventionally, isobutane, which has excellent foamability with respect to polystyrene resin, has been used together with HFO. As a result, since isobutane has a higher thermal conductivity than HFO, the higher the isobutane content, the higher the thermal conductivity. There was room for

This low thermal conductivity retention effect may be improved by using a styrene-(meth)acrylic acid ester copolymer instead of polystyrene resin. This is because HFO, particularly HFO-1234ze, has a very low gas permeability with respect to a styrene-(meth)acrylic acid ester copolymer, so that HFO can be retained for a long period of time and low thermal conductivity can be maintained. However, resins containing styrene-(meth)acrylic acid ester copolymer as a main component have a problem of poor foamability. Therefore, conventionally, in the case of a base resin containing a styrene-(meth)acrylic acid ester copolymer as a main component, the higher the ratio of the (meth)acrylic acid ester component in the base resin, the better the foamability. It was thought that foamability would be reduced due to the lower content of styrene components.

The inventors of the present invention used a base resin containing a styrene-(meth)acrylic acid ester copolymer as a main component, and when they tried extrusion foaming using the HFO, unexpectedly, (meth)acrylic acid The inventors have found that the higher the content of the ester component, the better the moldability and the better the extruded foam board can be obtained, and arrived at the present invention. If the content of the (meth)acrylic acid ester component derived from the styrene-(meth)acrylic acid ester copolymer in the base resin is too low, the HFO tends to separate from the foamed plate, resulting in frequent gas spots. As a result, the appearance of the surface of the extruded foam plate tends to deteriorate. On the other hand, if the content is too high, the moldability tends to deteriorate, making it impossible to obtain an extruded foam board.

When HFO is used as a physical blowing agent, the base resin having a high ratio of (meth)acrylic acid ester component has excellent foamability because HFO is a (meth)acrylic acid ester in the base resin. It is believed that the effect of plasticizing the component is greater than the effect of plasticizing the polystyrene resin.

A brominated flame retardant can be preferably used as the flame retardant. Brominated flame retardants include tetrabromobisphenol A, tetrabromobisphenol-A-bis(2,3-dibromopropyl ether), tetrabromobisphenol-A-bis(2-bromoethyl ether), tetrabromobisphenol-A- Bis(allyl ether), tetrabromobisphenol-A-bis(2,3-dibromo-2-methylpropyl ether), tetrabromobisphenol S, tetrabromobisphenol-S-bis(2,3-dibromopropyl ether), hexa Bromocyclododecane, tetrabromocyclooctane, tris(2,3-dibromopropyl)isocyanurate, tribromophenol, decabromodiphenyloxide, tris(tribromoneopentyl)phosphate, brominated polystyrene, styrene-butadiene copolymer bromides, and the like. These compounds can be used singly or in combination of two or more. Among these brominated flame retardants, from the viewpoint of high thermal stability and high flame retardancy, in particular, tetrabromobisphenol-A-bis(2,3-dibromopropyl ether), tetrabromobisphenol-A-bis(2, 3-dibromo-2-methylpropyl ether), tris(2,3-dibromopropyl) isocyanurate, brominated styrene-butadiene copolymer are preferably used. These compounds can be used alone or in combination of two or more.

The blending amount of the flame retardant is high flame retardancy such as the flammability standard for extruded polystyrene foam insulation described in "Test Method A" specified in the flammability test method of JIS A9521: 2017. is preferably 1 part by mass, more preferably 3 parts by mass, with respect to 100 parts by mass of the base resin. In addition, in order to minimize the deterioration of the foamability during extrusion and the deterioration of the mechanical properties of the thermoplastic resin foam board, the upper limit of the amount of the flame retardant compounded is 10 parts by weight per 100 parts by weight of the base resin. Preferably, 7 parts by mass is more preferable.

Furthermore, in the present invention, for the purpose of further improving the flame retardancy of the extruded foam board, a flame retardant aid can be used in combination with the flame retardant. The flame retardant auxiliary includes 2,3-dimethyl-2,3-diphenylbutane, 2,3-diethyl-2,3-diphenylbutane, 3,4-dimethyl-3,4-diphenylhexane, 3,4 - diphenylalkanes and diphenylalkenes such as diethyl-3,4-diphenylhexane, 2,4-diphenyl-4-methyl-1-pentene, 2,4-diphenyl-4-ethyl-1-pentene, triphenylphosphate, cresyldi Nitrogen-containing cyclic compounds such as 2,6-xylenyl phosphate, antimony trioxide, diantimony pentoxide, ammonium sulfate, zinc stannate, cyanuric acid, isocyanuric acid, triallyl isocyanurate, melamine cyanurate, melamine, melam, and melem , silicone compounds, inorganic compounds such as boron oxide, zinc borate and zinc sulfide, and phosphorus compounds such as red phosphorus, ammonium polyphosphate and phosphazene. These compounds can be used alone or in combination of two or more.

As a method for blending the flame retardant with the thermoplastic resin, a predetermined proportion of the flame retardant is supplied to the raw material supply unit provided on the upstream side of the extruder together with the thermoplastic resin, and the thermoplastic resin is added in the extruder. A method of kneading with a resin can be mentioned. Alternatively, the flame retardant may be supplied into the thermoplastic resin melt from a flame retardant supply section provided in the extruder. When supplying the flame retardant to the extruder, a method of supplying a dry blend of the flame retardant and the thermoplastic resin to the extruder, a method of supplying a liquid flame retardant that has been heated and melted in advance into the extruder, A method of preparing a masterbatch containing a flame retardant and a thermoplastic resin as a base resin and supplying the masterbatch to an extruder can be employed. In particular, in order to improve dispersibility, it is preferable to adopt a method of preparing a masterbatch containing a flame retardant and supplying it to an extruder. The method of blending the auxiliary flame retardant is the same as the method of supplying the flame retardant.

In the method of the present invention, the base resin may be blended with a radiation inhibitor to further improve the heat insulating properties. Examples of the radiation inhibitor include metal oxides such as titanium oxide, metals such as aluminum, fine powders such as ceramics, carbon black and graphite, infrared shielding pigments, and hydrotalcite. These can use 1 type(s) or 2 or more types. The amount of the radiation suppressor compounded is generally 0.5 to 10 parts by weight, preferably 1 to 8 parts by weight, per 100 parts by weight of the base resin. The compounded amount of the radiation inhibitor means the total amount when two or more of them are used.

In addition, in the present invention, various additives such as cell control agents, coloring agents such as pigments and dyes, heat stabilizers, and fillers can be appropriately blended with the base resin, if necessary.

Examples of the foam control agent include inorganic powders such as talc, kaolin, mica, silica, calcium carbonate, barium sulfate, aluminum oxide, clay, bentonite, and diatomaceous earth, and conventionally known chemical foaming agents such as azodicarbodiamide. can be used. Among them, talc is preferable because it does not impair the flame retardancy and the cell diameter can be easily adjusted. In particular, it is preferable to use talc having a particle size of 0.1 to 20 μm, more preferably 0.5 to 15 μm, as defined in JIS Z8901:2006. The amount of the cell control agent to be added varies depending on the type of the cell control agent, the target cell diameter, etc., but is generally 0.01 to 8 parts by mass, further 0.01 to 5 parts by mass, per 100 parts by mass of the base resin. Parts by weight, especially 0.05 to 3 parts by weight are preferred.

The lower limit of the apparent density of the extruded foam board is preferably 20 kg/m ³ , more preferably 25 kg/m ³ , since the production stability and mechanical strength of the extruded foam board are improved. More preferably 30 kg/m ³ . Further, the upper limit of the apparent density is preferably 50 kg/m ³ , more preferably 45 kg/m ³ , and more preferably 40 kg/m ³ in order to improve heat insulation and ensure lightness. More preferred.

The thickness of the extruded foam board is appropriately set according to the purpose of use, and is not particularly limited, but from the viewpoint of use as a heat insulating material, it is preferably 25 mm or more, and 35 mm or more. is more preferable, and 45 mm or more is even more preferable. The upper limit of thickness is approximately 150 mm.

The cross-sectional area of the extruded foam board perpendicular to the extrusion direction and parallel to the thickness direction is preferably 100 cm ² or more, more preferably 300 cm ² or more, and still more preferably 400 cm ² or more.

Since the method of the present invention is excellent in production stability, it is possible to easily transfer the results of an experimental machine consisting of a small extruder to an actual production machine consisting of a large extruder. Therefore, an extruded foam board having a large cross-sectional area can be easily manufactured. On the other hand, if the manufacturing stability is lacking, the results of the small-scale experimental machine cannot be transferred to the large-scale actual manufacturing machine, and there is a possibility that an extruded foam board with a desired large cross-sectional area cannot be manufactured.

The closed cell ratio of the extruded foam board is preferably 85% or more, more preferably 90% or more, further preferably 92% or more, further preferably 95% or more, because the long-term heat insulation property is improved. is particularly preferred.

The closed cell rate of the extruded foam board is determined by cutting out cut samples from a total of five randomly selected locations on the extruded foam board and using them as measurement samples. Adopt the arithmetic mean. The cut sample is a sample without skin that is cut from the extruded foam plate to a size of 45 mm long x 20 mm wide x 25 mm thick. , Two samples (cut samples) cut into a size of 45 mm long×20 mm wide×12.5 mm thick are stacked and measured. In addition, the closed cell ratio S (%) is measured using an air comparison type hydrometer (for example, Toshiba Beckman Co., Ltd., air comparison type hydrometer, model: 930 type) according to procedure C of ASTM-D2856-70. It is calculated by the following formula (3) using the true volume Vx of the thermoplastic resin foam measured by.

S (%) = (Vx-W/ρ) x 100/(VA-W/ρ) (3)
Vx: true volume of the cut sample obtained by measurement with an air-comparative hydrometer (cm ³ ) (the sum of the volume of the resin constituting the cut sample of the foam and the total volume of the closed cells in the cut sample) equivalent to
VA: Apparent volume of the cut sample calculated from the outer dimensions of the cut sample used for measurement (cm ³ )
W: total weight of cut sample used for measurement (g)
ρ: Density of the base resin constituting the thermoplastic resin foam (g/cm ³ )

The thermal conductivity of the extruded foam board of the present invention one day after production is preferably 0.024 W/(m·K) or less, more preferably 0.023 W/(m·K) or less. , is more preferably 0.022 W/(m·K) or less, and particularly preferably 0.021 W/(m·K) or less.

In addition, the extruded foam of the present invention preferably has a thermal conductivity of 0.027 W/(m K) or less, more preferably 0.026 W/(m K) or less, after 1500 days from production. It is more preferably 0.025 W/(m·K) or less. In order for the extruded foam board to exhibit stable long-term heat insulation properties, it is preferable that the difference between the thermal conductivity after 1500 days from production and the thermal conductivity after 1 day from production is as small as possible.

In addition, the thermal conductivity is measured by cutting out a test piece having no skin of any length 200 mm × width 200 mm × thickness from the extruded foam plate immediately after production, and storing the test piece in an atmosphere of 23 ° C. and 50% humidity. JIS A1412-2: Measured based on the flat plate heat flow meter method (two heat flow meters, high temperature side 38°C, low temperature side 8°C, average temperature 23°C) described in JIS A1412-2:1999.

Note that the thermal conductivity after 1500 days from the production is measured in accordance with JIS A1486:2014 using a sample subjected to an accelerated test. According to this method, for example, a sample obtained by slicing an extruded foam board with a thickness of 50 mm to a thickness of 10 mm, the thermal conductivity measured 60 days after production is the same as that after about 1500 days after production of the extruded foam board. Corresponds to thermal conductivity.

EXAMPLES The present invention will be described in more detail below based on examples, but the present invention is not limited by the examples.

In Examples and Comparative Examples, extruded foam boards were produced using the following equipment and raw materials.

[Extruder]
A first extruder with an inner diameter of 180 mm and a second extruder with an inner diameter of 225 mm are connected in series, a physical foaming agent injection port is provided near the end of the first extruder, and a gap of 2.5 mm x width is provided at the outlet of the second extruder. A manufacturing apparatus was used in which a flat die having a rectangular resin outlet (die lip) with a cross section of 400 mm was connected.
A shaping device (guider) comprising a pair of upper and lower polytetrafluoroethylene resin plates was attached to the resin outlet of the flat die so that the upper and lower resin plates were parallel.

(Thermoplastic resin)
Styrene-(meth)acrylic acid ester copolymer (1) Abbreviated name “MS1”: Styrene-methyl methacrylate copolymer: “MS750” manufactured by Toyo Styrene Co., Ltd. (M component-75% by mass, styrene component-25% by mass %, melt viscosity (200° C., 100 sec ⁻¹ ) 2440 Pa s,)
(2) Abbreviated name “MS2”: Styrene-methyl methacrylate copolymer: “MS200” manufactured by Toyo Styrene Co., Ltd. (M component - 20% by mass, styrene component - 80% by mass, melt viscosity (200 ° C., 100 sec ^-1 ) 1980 Pa s)
(3) Abbreviated name “MS3”: Styrene-methyl methacrylate copolymer: Recycled raw material of Example 1 (M component-75% by mass, styrene component-25% by mass, melt viscosity (200 ° C., 100 sec ^-1 ) 2190 Pa・s)
(4) Abbreviated name "PMMA": Polymethyl methacrylate resin: "TF9" manufactured by Mitsubishi Chemical Corporation (M component - 100% by mass, styrene component - 0% by mass, melt viscosity (200 ° C., 100 sec ^-1 ) 3290 Pa · s)

The M component means a methacrylic acid ester component derived from a styrene-methacrylic acid ester copolymer.
For MS3, the extruded foam plate obtained in Example 1 was pulverized with a pulverizer, then supplied to a single-screw extruder with an inner diameter of 90 mm and L/D = 50, and kneaded at a maximum temperature of 220°C. The molten resin was extruded at a discharge rate of 250 kg/hour and pelletized to obtain a styrene-methyl methacrylate copolymer (MS3) in the form of pellets.

Table 1 summarizes the types, manufacturer/product names, and melt viscosities of the above resins.

The melt viscosity of the thermoplastic resin was measured by the following method using Capilograph 1D manufactured by Toyo Seiki Seisakusho Co., Ltd. A capillary with a hole diameter of 1.0 mm and a length of 10.0 mm was attached to the tip of a cylinder with a cylinder diameter of 9.55 mm and a length of 350 mm. ) was filled and sufficiently melted by preheating for 4 minutes, and the melt viscosity of the resin was measured under the condition of a shear rate of 100 sec ^-1 .

(physical blowing agent)
(1) Hydrofluoroolefin (HFO): 1,3,3,3-tetrafluoropropene (HFO-1234ze)
(2) Hydrofluoroolefin (HFO): 1-chloro-3,3,3-trifluoropropene (HFO-1233zd)
(3) isobutane (iB)
(4) Ethanol (EtOH)
(5) Water

(Flame retardants)
As a flame retardant, brominated butadiene-styrene block copolymer: "Emerald innovation 3000" manufactured by Lanxess Corporation was used.

(Air bubble control agent)
Talc: "High Filler #12" manufactured by Matsumura Sangyo Co., Ltd. was used as a cell control agent.

(Radiation inhibitor)
(1) Graphite: Nippon Graphite Industry Co., Ltd. “CP-N” (flaky graphite), primary particle size (d50) = 10 μm
(2) Titanium oxide: “JR-405” manufactured by Tayca Co., Ltd., primary particle size (d50) = 0.2 μm

Examples 1-11, Comparative Examples 1-5
Thermoplastic resins, flame retardants, talc, and radiation inhibitors of the types and blending ratios shown in Tables 2 and 3 (where the total blending amount of each resin is 100% by mass) are supplied to the first extruder. It is heated and kneaded to form a molten resin composition, a physical blowing agent is supplied thereto from the physical blowing agent injection port, and the molten resin composition further melt-kneaded in the first extruder is transferred to the subsequent second extruder to obtain a resin. After adjusting the temperature to 119 ° C., which is suitable for foaming, the material is extruded from the die lip into a guider at a discharge rate of 700 kg / hour and a die pressure of 6 to 8 MPa, and is formed into a plate by passing through the guider while foaming. Then, a master plate having a thickness of 55 mm was obtained. Thereafter, the surface layer skins on both sides of the original plate were evenly shaved to obtain a plate-shaped extruded foam plate (width 910 mm×length 2000 mm×thickness 50 mm).

Tables 4 and 5 show the results of measuring and evaluating various physical properties of the produced extruded foam board.

In Tables 4 and 5, the apparent density, closed cell content, cell diameter, and thermal conductivity were measured by the following methods, and moldability and production stability were evaluated according to the following criteria.

<Apparent density>
The apparent density was measured according to JIS K6767 (1999). A rectangular parallelepiped sample of 50 mm long × 50 mm wide × 50 mm thick was cut out from a total of three locations near the width direction center and width direction both ends of each extruded foam board, and the apparent density of each sample was measured. Arithmetic mean value of was taken as apparent density.

<Closed cell rate>
Cut samples are cut out from a total of three locations near the center in the width direction and near both ends in the width direction of the extruded foam board to be used as measurement samples. The value was taken as the closed cell fraction. The cut sample used was obtained by cutting an extruded foam plate into a size of 25 mm long×25 mm wide×25 mm thick.
The closed cell ratio of the sample is measured using an air comparison type hydrometer (manufactured by Toshiba Beckman Co., Ltd., model: 930) according to procedure C of ASTM-D2856-70, and obtained from the above formula (3). The arithmetic mean value of was taken as the closed cell ratio.

<Bubble diameter>
The cell diameter is the central part (thickness of the foam board 5 mm above and below in the width direction from the center centered on the line that bisects the direction), the magnification is in the range of about 50 to 200 times so that the number of cells in the photograph is about 200 to 500 On each photograph, using the image processing software NS2K-pro manufactured by Nanosystem Co., Ltd., the diameter of each bubble in the thickness direction was obtained, and the arithmetic average value was taken as the diameter of the bubble.

<Thermal conductivity>
From the extruded foam plate immediately after production, a test piece with no skin of 200 mm long × 200 mm wide × 50 mm thick was cut out, and the test piece was stored for 1 day in an atmosphere of 23 ° C. and 50% humidity. It was measured based on A1412-2 (1999) plate heat flow meter method (two heat flow meters method, high temperature side 38°C, low temperature side 8°C, average temperature 23°C).

In addition, the thermal conductivity after 1500 days of manufacture is based on JIS A1486 (2014), and is obtained by measuring the thermal conductivity of a test piece that has been subjected to the test method A of the long-term change acceleration test of thermal resistance. value. Specifically, in the central part of the extruded foam plate with a thickness of 50 mm immediately after production, a test piece of 200 mm × 200 mm × 10 mm without a molded skin was cut out evenly from both sides, and a constant temperature of 23 ° C. and a relative humidity of 50% Stored in a constant humidity room, using a test piece 60 days after production (equivalent to 1500 days after production of an extruded foam plate with a thickness of 50 mm), a flat plate heat flow meter method (two heat flow meters method) described in JIS A1412-2 (1999) , hot side 38° C., cold side 8° C., average temperature 23° C.).

<Moldability>
Evaluation of moldability was performed according to the following criteria.
⊚: The foamed state was good, and a plate-like base plate with an extremely good appearance, free from roughness and gas spots on the surface, was stably obtained.
◯: The foaming state was relatively good, and although roughness and gas spots rarely occurred on the surface, a generally good plate-like substrate was obtained.
x: Many rough surfaces and gas spots were observed on the surface of the foamed plate, and a good plate-like original plate and extruded foamed plate could not be obtained.

<Manufacturing stability>
Production stability was evaluated according to the following criteria.
◯: When the molten resin composition was foamed and molded into a plate shape with a molding tool, a base plate could be stably produced without any problems.
x: When the molten resin composition was foamed and molded into a plate with a molding tool, the original plate was frequently broken.

Example 1 is an example in which a styrene-(meth)methyl acrylate copolymer having a (meth)acrylic acid ester component content of 75% by mass is used as the base resin, and HFO-1234ze is used as the physical blowing agent. be. The extruded foam board was excellent in moldability and manufacturing stability, and the obtained extruded foam board had a small long-term thermal conductivity.
In Example 2, a styrene-(meth)methyl acrylate copolymer having a (meth)acrylic acid ester component content of 62.5% by mass was used as the base resin, and HFO-1234ze was used as the physical blowing agent. Except for this, this is an example of producing an extruded foam board in the same manner as in Example 1. The extruded foam board was excellent in moldability and manufacturing stability, and the obtained extruded foam board had a small long-term thermal conductivity.
In Example 3, a styrene-methyl (meth)acrylate copolymer having a (meth)acrylic acid ester component content of 62.5% by mass was used as the base resin, and HFO-1234ze (0.5% by mass) was used as the physical blowing agent. 7 mol %) and HFO-1233zd (0.3 mol %), except for using a mixed foaming agent. The extruded foam board was excellent in moldability and manufacturing stability, and the obtained extruded foam board had a small long-term thermal conductivity.
In Example 4, a styrene-(meth)methyl acrylate copolymer having a (meth)acrylic acid ester component content of 50% by mass was used as the base resin, and HFO-1234ze (0.8 mol%) was used as the physical blowing agent. ) and HFO-1233zd (0.2 mol %) in the same manner as in Example 3 except that a mixed foaming agent was used. The extruded foam board was excellent in moldability and manufacturing stability, and the obtained extruded foam board had a small long-term thermal conductivity.
In Example 5, an extruded foam board was produced in the same manner as in Example 3, except that a styrene-methyl (meth)acrylate copolymer having a (meth)acrylic acid ester component content of 50% by mass was used as the base resin. This is a manufactured example. The extruded foam board was excellent in moldability and manufacturing stability, and the obtained extruded foam board had a small long-term thermal conductivity.
In Example 6, an extruded foam board was produced in the same manner as in Example 1, except that a mixed foaming agent of HFO-1234ze (0.4 mol%) and HFO-1233zd (0.6 mol%) was used as the physical foaming agent. For example. The extruded foam board was excellent in formability and production stability, and the obtained extruded foam board had low long-term thermal conductivity.
Example 7 is an example of producing an extruded foam board in the same manner as in Example 1, except that a mixed foaming agent of HFO-1234ze (0.5 mol%) and isobutane (0.5 mol%) was used as a physical foaming agent. be. The extruded foam board was excellent in moldability and manufacturing stability, and the obtained extruded foam board had a small long-term thermal conductivity.
Example 8 is an example of producing an extruded foam board in the same manner as in Example 1, except that the amount of talc added was reduced and a radiation suppressor (graphite/titanium oxide) was added. The extruded foam board was excellent in formability and manufacturing stability, and the obtained extruded foam board had a small long-term thermal conductivity.
Example 9 is an example of producing an extruded foam board in the same manner as in Example 1, except that a mixed resin containing the recovered resin of the extruded foam board obtained in Example 1 was used as the base resin. The extruded foam board was excellent in formability and manufacturing stability, and the obtained extruded foam board had a small long-term thermal conductivity.
In Example 10, extrusion foaming was performed in the same manner as in Example 7, except that a styrene-methyl (meth)acrylate copolymer having a (meth)acrylic acid ester component content of 32.9% by mass was used as the base resin. This is an example of manufacturing a plate. The extruded foam board was excellent in formability and manufacturing stability, and the obtained extruded foam board had a small long-term thermal conductivity.
In Example 11, extrusion foaming was performed in the same manner as in Example 7, except that a styrene-methyl (meth)acrylate copolymer having a (meth)acrylic acid ester component content of 27.6% by mass was used as the base resin. This is an example of manufacturing a plate. The extruded foam board was excellent in formability and manufacturing stability, and the obtained extruded foam board had a small long-term thermal conductivity.

Comparative Example 1 uses a styrene-(meth)methyl acrylate copolymer having a (meth)acrylic acid ester component content of 20% by mass, and uses HFO-1234ze (0.8 mol%) and HFO as physical blowing agents. This is an example of producing an extruded foam board in the same manner as in Example 1, except that a mixed foaming agent with -1233zd (0.2 mol %) was used. Since the content of the (meth)acrylic acid ester component in the base resin was low, many gas spots occurred, and the resulting extruded foam board had poor moldability.
Comparative Example 2 is an example in which an extruded foam board was produced in the same manner as in Example 1, except that a styrene-methyl (meth)acrylate copolymer having a (meth)acrylic acid ester component content of 20% by mass was used. be. Gas spots occurred more frequently than in Comparative Example 1, and an extruded foam board could not be obtained.
Comparative Example 3 is an example of producing an extruded foam board in the same manner as in Example 3, except that polymethyl methacrylate resin (PMMA) was used as the base resin. Shrinkage immediately after production was large, and an extruded foam board could not be obtained.
Comparative Example 4 is an example of producing an extruded foam board in the same manner as in Example 1, except that a polymethyl methacrylate resin (PMMA) was used as the base resin. Shrinkage immediately after production was large, and an extruded foam board could not be obtained.
In Comparative Example 5, a styrene-methyl (meth)acrylate copolymer having a (meth)acrylic acid ester component content of 62.5% by mass was used as the base resin, and HFO-1234ze (0.5%) was used as the physical blowing agent. 2 mol %) and isobutane (0.8 mol %). Production stability was poor, and breakage occurred frequently in the forming device (guider).

Claims (7)

A method for producing an extruded thermoplastic resin foam plate, which includes a step of extruding and foaming a foamable resin composition obtained by kneading a base resin, a physical foaming agent, and a flame retardant, and molding the composition into a plate using a molding tool,
The base resin contains a styrene-(meth)acrylic acid ester copolymer as a main component, and contains a (meth)acrylic acid ester component derived from the styrene-(meth)acrylic acid ester copolymer in the base resin. is 25% by mass or more and 90% by mass or less, the total amount of the physical blowing agent is 0.8 mol or more and 1.3 mol or less per 1 kg of the base resin, and the physical blowing agent contains a hydrofluoroolefin. and a total amount of the hydrofluoroolefin compounded is 0.5 mol or more and 1.3 mol or less per 1 kg of the base resin.
2. The method according to claim 1, wherein the content of the (meth)acrylic acid ester component derived from the styrene-(meth)acrylic acid ester copolymer in the base resin is 50% by mass or more and 80% by mass or less. A method for producing the thermoplastic extruded foam board described.
3. The method for producing a thermoplastic resin foam board according to claim 1, wherein the styrene-(meth)acrylate copolymer is a styrene-methyl methacrylate copolymer.
The thermoplastic resin foam plate according to any one of claims 1 to 3, wherein the total amount of the hydrofluoroolefin compounded is 0.5 mol or more and 1.0 mol or less per 1 kg of the base resin. manufacturing method.
the hydrofluoroolefin comprises 1-chloro-3,3,3-trifluoropropene (HFO-1233zd) and/or 1,3,3,3-tetrafluoropropene (HFO-1234ze);
The total amount of 1-chloro-3,3,3-trifluoropropene (HFO-1233zd) and/or 1,3,3,3-tetrafluoropropene (HFO-1234ze) compounded per 1 kg of the base resin 5. The method for producing a thermoplastic resin foam board according to any one of claims 1 to 4, wherein the total amount is 0.5 mol or more.
The hydrofluoroolefin contains 1,3,3,3-tetrafluoropropene (HFO-1234ze), and the amount of 1,3,3,3-tetrafluoropropene (HFO-1234ze) is added to 1 kg of the base resin. 5. The method for producing a thermoplastic resin foam board according to any one of claims 1 to 4, wherein the content is 0.5 mol or more.
The content (X) [% by mass] of the (meth)acrylate component derived from the styrene-(meth)acrylate copolymer in the base resin, and 1,3,3,3-tetrafluoropropene 7. The method for producing a thermoplastic resin foam board according to claim 6, wherein the compounding amount (Y) [mol/1 kg of base resin] of (HFO-1234ze) satisfies the following formula (1).

Y<0.024X−0.4 (1)