JP6842324B2 - Method for manufacturing styrene resin extruded foam - Google Patents

Description

The present invention relates to a method for producing a styrene resin extruded foam obtained by extrusion foaming using a styrene resin and a foaming agent.

A styrene-based resin extruded foam is generally obtained by heating and melting a styrene-based resin composition using an extruder or the like, then adding a foaming agent under high-pressure conditions, cooling to a predetermined resin temperature, and then applying the styrene-based resin composition to a low pressure. Manufactured continuously by extruding into the region.

The styrene-based resin extruded foam is used, for example, as a heat insulating material for structures because of its good workability and heat insulating properties. In recent years, there has been an increasing demand for energy saving in houses and buildings, and technological development of higher heat insulating foam than before is desired.

As a method for producing a highly heat-insulating foam, a method of controlling the bubble diameter of the extruded foam within a predetermined range, a method of adding a heat ray radiation inhibitor, and a method of using a foaming agent having low thermal conductivity are proposed. Has been done.

For example, Patent Document 1 proposes a manufacturing method in which the average cell diameter in the thickness direction of an extruded foam is set to be fine cells of 0.05 to 0.18 mm, and the bubble deformation rate of the extruded foam is controlled.

Further, Patent Document 2 proposes a production method in which graphite or titanium oxide is added in a predetermined range as a heat ray radiation inhibitor.

Further, a method for producing a styrene resin extruded foam using an environment-friendly fluorinated olefin (hydrofluoroolefin, also referred to as HFO) having an ozone depletion potential of 0 (zero) and a small global warming potential. Have been proposed (see, for example, Patent Documents 3 to 6).

On the other hand, there is an example in which polyethylene glycol is added to a styrene resin as in the present invention. For example, Patent Documents 7 to 8 propose a method of adding polyethylene glycol or the like to foamable styrene resin particles for the purpose of preventing abnormal noise and antistatic.

JP-A-2004-59595 JP 2013-221110 Special table 2008-546892 JP 2013-194101 Special table 2010-522808 WO15 / 093195 JP 2015-11418 JP 2013-209637

However, the techniques described in Patent Documents 1 to 8 have an excellent heat insulating property, and are aimed at obtaining a styrene resin extruded foam having a beautiful appearance and a sufficient thickness suitable for use. It wasn't enough.

An object of the present invention is to easily produce an extruded styrene resin foam having excellent heat insulating properties, a beautiful appearance, and a sufficient thickness suitable for use.

As a result of diligent studies to solve the above problems, the present inventors used polyethylene glycol as a moldability improving agent in the production of styrene resin extruded foam, and further used polyethylene glycol and a styrene resin as a base material. The present invention has been completed by adding the resin in the form of a masterbatch.

That is, the present invention has the following configuration.

[1] The present invention comprises a step of adding a masterbatch having a styrene resin content of 50% by weight or more and 99% by weight or less and a polyethylene glycol content of 1% by weight or more and 50% by weight or less. , A method for producing a styrene resin extruded foam.

[2] The step of adding the masterbatch to the styrene resin so that the content of polyethylene glycol is 0.05 parts by weight or more and 5.0 parts by weight or less with respect to 100 parts by weight of the styrene resin is included. The method for producing a styrene-based resin extruded foam according to [1], which is characteristic.

[3] The method according to [1] or [2], wherein the amount of the hydrofluoroolefin added is 3.0 parts by weight or more and 14.0 parts by weight or less with respect to 100 parts by weight of the styrene resin. A method for producing an extruded styrene resin foam.

[4] The styrene according to any one of [1] to [3], which contains 1.0 part by weight or more and 5.0 parts by weight or less of graphite with respect to 100 parts by weight of the styrene resin. A method for producing an extruded resin foam.

[5] In any one of [1] to [4], the brominated flame retardant is contained in an amount of 0.5 parts by weight or more and 5.0 parts by weight or less with respect to 100 parts by weight of the styrene resin. The method for producing an extruded styrene resin foam according to the above method.

[6] The method for producing a styrene-based resin extruded foam according to any one of [1] to [5], wherein the polyethylene glycol has an average molecular weight of 1000 or more and 25,000 or less.

[7] The method for producing a styrene-based resin extruded foam according to any one of [3] to [6], wherein the hydrofluoroolefin is tetrafluoropropene.

[8] The method for producing a styrene-based resin extruded foam according to any one of [1] to [7], wherein the thickness of the styrene-based resin extruded foam is 10 mm or more and 150 mm or less.

[9] The styrene-based resin extruded foam has an apparent density of 20 kg / m ³ or more and 60 kg / m ³ or less, and a closed cell ratio of 80% or more. The method for producing an extruded styrene resin foam according to any one of the following items.

According to the present invention, it is possible to easily produce a styrene-based resin extruded foam having excellent heat insulating properties, having a beautiful appearance, and having a sufficient thickness suitable for use.

An embodiment of the present invention will be described below, but the present invention is not limited thereto. The present invention is not limited to the configurations described below, and various modifications can be made within the scope of the claims. The technical scope of the present invention also includes embodiments and / or examples obtained by appropriately combining the technical means disclosed in different embodiments and / or examples. In addition, all the academic documents and patent documents described in the present specification are incorporated as references in the present specification. Further, unless otherwise specified in the present specification, "A to B" representing a numerical range is intended to be "A or more (including A and larger than A) and B or less (including B and smaller than B)".

As a result of diligent studies by the present inventors, it has been found that the above-mentioned Patent Documents 1 to 8 have the following problems. Specifically, first, in the technique described in Patent Document 1, when the average cell diameter is set to a fine range, the distance between the cell walls of the foam is shortened, so that the cells are extruded and foamed to give a shape. There is a problem that the movable range of the extruded foam is narrow, it is difficult to deform, it is difficult to give a beautiful surface to the extruded foam, and it is not easy to increase the thickness of the extruded foam.

Next, in the technique described in Patent Document 2, when a large amount of solid additive is used, the bubbles in the foam become finer due to the increase in nucleation points, which causes the same problem as the technique described in Patent Document 1. there were. In addition, there is a problem that the elongation of the resin itself deteriorates, and it becomes more difficult to impart a beautiful surface to the extruded foam and to increase the thickness of the extruded foam.

Further, in the techniques described in Patent Documents 3 to 6, the hydrofluoroolefins used in these conventional techniques have low solubility in a styrene-based resin and are quickly separated from the styrene-based resin during extrusion foaming. The separated hydrofluoroolefin becomes a nucleation point and the cell diameter becomes finer, and the resin is cooled and solidified (resin elongation deteriorates) due to the latent heat of vaporization of the hydrofluoroolefin, which is the same as the technique described in Patent Document 1. There was a problem.

As described above, all of the prior arts for producing a highly heat-insulating foam inhibit the deformation of bubbles in the foam when the extruded foam is extruded and molded, and / or the resin itself. There was a problem in deteriorating the elongation of the extruded foam, imparting a beautiful surface to the extruded foam, and increasing the thickness of the extruded foam. Therefore, the prior art for producing a highly heat-insulating foam has led to easily obtaining a styrene-based resin extruded foam having excellent heat-insulating properties, a beautiful appearance, and / or a sufficient thickness. It was not, and still had problems.

The techniques described in Patent Documents 7 to 8 are for solving the above-mentioned problems peculiar to foamable resin particles such as noise prevention and antistatic, and are examples in which polyethylene glycol is added to the extruded foam. Not yet.

The present inventor has completed the present invention in order to solve such a problem. An embodiment of the present invention will be described below.

[1. Styrene-based resin extruded foam]
The styrene resin extruded foam according to one embodiment of the present invention was added in the form of a masterbatch composed of 50% by weight or more and 99% by weight or less of the styrene resin and 1% by weight or more and 50% by weight or less of polyethylene glycol. Contains polyethylene glycol. Further, a styrene-based resin composition containing an appropriate amount of other additives, if necessary, is heated and melted using an extruder or the like to obtain a resin melt. Next, a foaming agent is added to the obtained resin composition under high pressure conditions and cooled to a predetermined resin temperature. Then, by extruding the resin melt containing the foaming agent into the low pressure region, the styrene-based resin extruded foam can be stably and continuously produced.

In one embodiment of the present invention, polyethylene glycol is used as a moldability improver to impart a beautiful surface to the extruded foam and / or to increase the thickness of the extruded foam (that is, extruded foam). (Improving the formability of the body) becomes possible. The effect of improving the moldability of polyethylene glycol is presumed as follows. That is, when the styrene-based resin extruded foam contains polyethylene glycol, the dispersibility and solubility of the foaming agent (for example, i-butane and / or hydrofluoroolefin) in the resin melt are improved. When the dispersibility and solubility of the foaming agent in the resin melt are improved, the vaporization amount or the vaporization rate of the foaming agent immediately after foaming of the extruded foam is suppressed. As a result, at the subsequent molding timing, the plasticizing effect of the resin melt by the foaming agent remaining in the resin melt can be maintained, and the cooling and solidification of the resin melt due to the latent heat of vaporization of the foaming agent can be suppressed. In addition, it is considered that the extruded foam and / or the resin melt has sufficient plasticity for imparting the shape of the extruded foam and the resin melt.

The content of the polyethylene glycol in the styrene resin extruded foam is 0.05 parts by weight or more and 5.0 parts by weight or less with respect to 100 parts by weight of the styrene resin, but 0.1 parts by weight or more and 3.0 parts by weight. It is preferably 0.2 parts by weight or more, and 1.0 part by weight or less is particularly preferable. If the content of polyethylene glycol is less than 0.05 parts by weight, the effect of imparting surface properties and the effect of thickening tend to be insufficient. On the other hand, when the content of polyethylene glycol exceeds 5.0 parts by weight, the content of polyethylene glycol is excessive, which impairs extrudability, foamability, and molding stability during production, heat resistance of the extruded foam, and the like. There is a risk of deteriorating various characteristics of.

In order to make polyethylene glycol the content in one embodiment of the present invention, the amount of polyethylene glycol added to the styrene resin composition is 0.05 parts by weight or more with respect to 100 parts by weight of the styrene resin. It may be 5.0 parts by weight or less.

The average molecular weight of the polyethylene glycol used in one embodiment of the present invention is not particularly limited, but is preferably 1000 or more and 25,000 or less, more preferably 1500 or more and 20000 or less, and particularly preferably 3000 or more and 15000 or less. These polyethylene glycols having different average molecular weights may be used alone or in combination of two or more. When the average molecular weight of polyethylene glycol is less than 1000, the freezing point of polyethylene glycol is low and the polyethylene glycol is in a liquid state at room temperature. Therefore, depending on the amount used, for example, the handleability in the dry blending step during the production of extruded foam is inferior. In addition, there is a risk of affecting various properties of the extruded foam, such as surface slime due to bleeding out of polyethylene glycol from the inside to the surface of the extruded foam. On the other hand, when the molecular weight of polyethylene glycol is 1000 or more and 25,000 or less, the freezing point is higher than normal temperature, the handling property is excellent, bleed-out does not occur, the freezing point is lower than the extrusion foam molding temperature, and the styrene type at the time of extrusion foam molding. Since the plasticizing effect can also be imparted to the resin, it is possible to exert a sufficient surface property imparting effect on the styrene resin extruded foam and a sufficient thicknessing effect. When the molecular weight of polyethylene glycol exceeds 25,000, it exists as a solid at the extrusion foaming temperature, the plasticizing effect cannot be imparted to the styrene resin at the time of extrusion foam molding, and the effect of imparting sufficient surface properties to the styrene resin extruded foam. , And there is a risk that sufficient thicknessing effect cannot be exhibited.

In one embodiment of the present invention, polyethylene glycol is added in the form of a masterbatch using a styrene resin as a base resin, so that even when a styrene resin extruded foam is produced using polyethylene glycol, it takes a long time. It is possible to maintain a desired discharge amount over the entire period and perform stable production. As described above, polyethylene glycol is considered to improve the dispersibility and solubility of the foaming agent in the resin melt, and has the effect of improving the moldability of the styrene resin extruded foam, but on the other hand. The compatibility between the styrene resin and polyethylene glycol itself is not good. Therefore, when polyethylene glycol is added without making it a masterbatch, after a long time has passed since the start of production using polyethylene glycol, polyethylene glycol that could not be completely mixed with the styrene resin near the resin mixture supply part of the extruder Due to the accumulation, the screw does not carry the resin mixture, so-called slippage reduces the discharge amount. By adding polyethylene glycol as a masterbatch as in the present invention, it is possible to prevent the polyethylene glycol from being completely mixed with the styrene resin.

In one embodiment of the present invention, the styrene resin content in the polyethylene glycol masterbatch is 50% by weight or more and 99% by weight or less, preferably 60% by weight or more and 99% by weight or less, and 70% by weight or more and 99% by weight or less. The following is more preferable. Further, the polyethylene glycol content in the polyethylene glycol masterbatch is 1% by weight or more and 50% by weight or less, preferably 1% by weight or more and 40% by weight or less, and more preferably 1% by weight or more and 30% by weight or less. If the polyethylene glycol content is less than 1% by weight, it is added at the time of manufacturing the styrene resin extruded foam, and a large amount of masterbatch is required to exert a sufficient moldability improving effect, so that the manufacturing cost is high. It gets higher. On the other hand, when the polyethylene glycol content exceeds 50%, the polyethylene glycol content is too high, so that the dispersion of polyethylene glycol in the masterbatch becomes non-uniform, and the shape when cut and pelletized becomes non-uniform. Or, polyethylene glycol partially bleeds out to the surface of the masterbatch, which makes it difficult to manufacture the polyethylene glycol masterbatch.

In one embodiment of the present invention, the amount of the polyethylene glycol masterbatch added is preferably 1.0 part by weight or more and 60 parts by weight or less with respect to 100 parts by weight of the styrene resin (excluding the polystyrene resin in the masterbatch). , 2.0 parts by weight or more and 50 parts by weight or less is more preferable, and 3.0 parts by weight or more and 40 parts by weight or less is particularly preferable. If the addition amount of the polyethylene glycol masterbatch is less than 1.0 part by weight, the amount of the masterbatch to be added is too small, and depending on the addition equipment selected, the influence of uneven distribution during mixing with the styrene resin becomes large, and the moldability is improved. There is a risk that the effect will not be exhibited stably. On the other hand, if the amount of the polyethylene glycol masterbatch added exceeds 60 parts by weight, the amount of the masterbatch used is too large, and the production cost increases.

The polyethylene glycol masterbatch according to the embodiment of the present invention can be produced by, for example, an extruder, a kneader, a Banbury mixer, a roll or the like. Although not particularly limited, as an example of a specific manufacturing method, various additives such as styrene resin, polyethylene glycol, and if necessary, a stabilizer are added to a heated and melted portion of a screw type extruder or the like. Supply to. A mixture of styrene resin, polyethylene glycol, and various additives is melt-kneaded to form a fluidized gel, and a strand-shaped resin extruded through a die with small holes attached to the tip of the extruder is passed through a water tank. After being cooled and solidified, it is cut to obtain a master batch in the form of pellets or particles. As a method of adding polyethylene glycol and various additives to the styrene resin, polyethylene glycol, a method of mixing various additives and the styrene resin by dry blend, or polyethylene glycol by a supply facility different from the styrene resin. , A method of supplying various additives to the extruder, or a method of supplying styrene resin to the extruder and heating and melting it, and then supplying polyethylene glycol and various additives from the middle of the extruder by another supply facility, etc. Can be mentioned. Further, as a method of supplying polyethylene glycol and various additives from the middle of the extruder by another supply facility, depending on the nature of the additive used, the method of adding the polyethylene glycol as it is or the method of adding it in a liquid state by heating. The method etc. can be mentioned. The heating temperature in the heat-melting portion may be at least the temperature at which the styrene-based resin used melts, and is preferably at least a temperature at which molecular deterioration of the resin is suppressed as much as possible, for example, about 150 ° C. to 260 ° C. The melt-kneading time in the heat-melting section is uniquely defined because it differs depending on the extrusion amount of the styrene resin per unit time and / or the type of extruder used as the heat-melting section and used as the melt-kneading section. This is not possible, and the time required for the styrene resin, polyethylene glycol, and various additives to be uniformly dispersed and mixed is appropriately set.

The styrene-based resin used in one embodiment of the present invention is not particularly limited, and (i) styrene such as styrene, methylstyrene, ethylstyrene, isopropylstyrene, dimethylstyrene, bromostyrene, chlorostyrene, vinyltoluene, vinylxylene and the like. A copolymer of a homopolymer of a system monomer or a copolymer composed of a combination of two or more kinds of monomers, or (ii) the styrene-based monomer and divinylbenzene, butadiene, acrylic acid, methacrylic acid, methyl acrylate. , A copolymer obtained by copolymerizing one or more of monomers such as methyl methacrylate, acrylonitrile, maleic anhydride, and itaconic anhydride. Acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, maleic anhydride, itaconic anhydride and the like to be copolymerized with the styrene-based monomer can be used as the compressive strength of the produced styrene-based resin extruded foam. An amount that does not deteriorate the physical properties of the above can be used. Further, the styrene-based resin used in one embodiment of the present invention is not limited to the homopolymer or copolymer of the styrene-based monomer, but the homopolymer or copolymer of the styrene-based monomer and the above-mentioned. It may be a homopolymer of other monomers or a blend with a copolymer. For example, the styrene-based resin used in one embodiment of the present invention may be a blend of a homopolymer or copolymer of the styrene-based monomer and diene-based rubber-reinforced polystyrene or acrylic-based rubber-reinforced polystyrene. Good. Further, the styrene resin used in one embodiment of the present invention is a styrene resin having a branched structure for the purpose of adjusting the melt flow rate (hereinafter referred to as MFR), the melt viscosity during molding, the melt tension, and the like. There may be.

As the styrene resin in one embodiment of the present invention, using a styrene resin having an MFR of 0.1 to 50 g / 10 minutes is excellent in (i) molding processability during extrusion foam molding, and (ii) molding. It is easy to adjust the discharge amount during processing, the thickness, width, apparent density, and closed cell ratio of the obtained styrene resin extruded foam to desired values, and (iii) foamability (thickness, width of foam, It is easy to adjust the apparent density, closed cell ratio, surface properties, etc. to the desired situation), (iv) a styrene resin extruded foam with excellent appearance can be obtained, and (v) characteristics. It is preferable from the viewpoint that a styrene resin extruded foam having a good balance (for example, mechanical strength such as compressive strength, bending strength or bending amount, toughness, etc.) can be obtained. Further, the MFR of the styrene resin is more preferably 0.3 to 30 g / 10 minutes, preferably 0.5 to 25 g / 10 minutes, from the viewpoint of the balance between molding processability and foamability, mechanical strength and toughness. Especially preferable. In one embodiment of the present invention, the MFR is measured by the method A of JIS K7210 (1999) and the test condition H.

In one embodiment of the present invention, among the above-mentioned styrene-based resins, polystyrene resin is particularly preferable from the viewpoint of economy and processability. When higher heat resistance is required for the extruded foam, it is preferable to use a styrene-acrylonitrile copolymer, (meth) acrylic acid copolymer polystyrene, and maleic anhydride-modified polystyrene. Further, when the extruded foam is required to have higher impact resistance, it is preferable to use rubber-reinforced polystyrene. These styrene resins may be used alone, or two or more different styrene resins having different copolymerization components, molecular weights, molecular weight distributions, branched structures, and / or MFRs may be mixed and used. ..

As the foaming agent used in one embodiment of the present invention, saturated hydrocarbons having 3 to 5 carbon atoms or hydrofluoroolefins can be used. These foaming agents may be used alone or in combination of two or more.

Examples of saturated hydrocarbons having 3 to 5 carbon atoms used in one embodiment of the present invention include propane, n-butane, i-butane, n-pentane, i-pentane, and neopentane. Among these saturated hydrocarbons having 3 to 5 carbon atoms, propane, n-butane, i-butane, or a mixture thereof is preferable from the viewpoint of foamability. Further, from the viewpoint of heat insulating performance of the foam, n-butane, i-butane (hereinafter, also referred to as "isobutane"), or a mixture thereof is preferable, and i-butane is particularly preferable.

The hydrofluoroolefin used in one embodiment of the present invention is not particularly limited, but tetrafluoropropene is preferable from the viewpoint of low thermal conductivity and safety of the gas. Specifically, trans-1,3,3,3-tetrafluoropropene (trans-HFO-1234ze), cis-1,3,3,3-tetrafluoropropene (cis-HFO-1234ze), 2,3. Examples thereof include 3,3-tetrafluoropropene (trans-HFO-1234yf). Further, the hydrofluoroolefin used in the present invention may be a chlorinated hydrochlorofluoroolefin. The hydrochlorofluoroolefin is not particularly limited, but hydrochlorotrifluoropropene is preferable from the viewpoint of low thermal conductivity and safety of the gas. Specific examples thereof include trans-1-chloro-3,3,3-trifluoropropene (trans-HCFO-1233zd). These hydrofluoroolefins may be used alone or in combination of two or more.

The amount of the hydrofluoroolefin added according to the embodiment of the present invention is preferably 3.0 parts by weight or more and 14.0 parts by weight or less with respect to 100 parts by weight of the styrene resin, and 4.0 parts by weight or more and 13.0 parts by weight. More preferably, it is 4.5 parts by weight or more and 12.0 parts by weight or less. When the amount of the hydrofluoroolefin added is less than 3.0 parts by weight with respect to 100 parts by weight of the styrene resin, the effect of improving the heat insulating property by the hydrofluoroolefin cannot be expected so much. On the other hand, when the amount of hydrofluoroolefin added exceeds 14.0 parts by weight with respect to 100 parts by weight of the styrene resin, the hydrofluoroolefin is separated from the resin melt during extrusion foaming and is applied to the surface of the extrusion foam. There is a risk that spot pores (traces of local lumps of hydrofluoroolefin penetrating the surface of the extruded foam and being released to the outside air) may be generated, or the closed cell ratio may decrease and the heat insulating property may be impaired.

Hydrofluoroolefins are environmentally friendly foaming agents with zero or extremely low ozone depletion potentials and very low global warming potentials. Moreover, since hydrofluoroolefins have low thermal conductivity in a gaseous state and are flame-retardant, they have excellent heat insulating properties in styrene resin extruded foams when used as a foaming agent for styrene resin extruded foams. , And flame retardancy can be imparted.

On the other hand, when a hydrofluoroolefin having low solubility in a styrene resin such as the above-mentioned tetrafluoropropene is used, the hydrofluoroolefin is separated from the resin melt and / or vaporized as the amount of addition is increased. By doing so, the hydrofluoroolefin becomes a nucleation point, (i) the bubbles of the foam are made finer, and (ii) the foaming agent remaining in the resin is reduced, and the plasticizing effect on the resin melt is reduced. (Iii) Cooling and solidification of the resin melt due to the latent heat of vaporization of the foaming agent, resulting in giving the extruded foam a beautiful surface and of the extruded foam molded product. It tends to be difficult to increase the thickness. In particular, when the amount of hydrofluoroolefin added exceeds 14.0 parts by weight with respect to 100 parts by weight of the styrene resin as described above, the moldability deteriorates with the occurrence of spot holes on the surface of the extruded foam. Becomes more prominent.

Depending on the desired foaming ratio, flame retardancy, and other characteristics of the foam, the amount of the saturated hydrocarbon having 3 to 5 carbon atoms and / or the hydrofluoroolefin added may be limited. If the addition amount is out of the desired range, the extrusion foam moldability may not be sufficient.

In one embodiment of the present invention, by further using another foaming agent, a plasticizing effect and / or a co-foaming effect at the time of foam production can be obtained, the extrusion pressure is reduced, and the foam can be stably produced. Is possible.

Other effervescent agents include, for example, ethers such as dimethyl ether, diethyl ether, methyl ethyl ether, isopropyl ether, n-butyl ether, diisopropyl ether, furan, furfural, 2-methylfuran, tetrahydrofuran, tetrahydropyran; dimethylketone, methylethylketone. , Diethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, methyl-i-butyl ketone, methyl-n-amyl ketone, methyl-n-hexyl ketone, ethyl-n-propyl ketone, ethyl-n-butyl ketone, etc. Ketones; saturated alcohols with 1 to 4 carbon atoms such as methanol, ethanol, propyl alcohol, i-propyl alcohol, butyl alcohol, i-butyl alcohol, t-butyl alcohol; methyl formic acid ester, ethyl formic acid ester, propyl formic acid ester , Carborates such as butyl formic acid, amyl ester of formic acid, methyl propionate, ethyl propionate; organic foaming agents such as alkyl halides such as methyl chloride and ethyl chloride, inorganic foaming agents such as water and carbon dioxide. , Azo compounds, chemical foaming agents such as tetrazole and the like can be used. These other foaming agents may be used alone or in combination of two or more.

Among other foaming agents, saturated alcohols having 1 to 4 carbon atoms, dimethyl ether, diethyl ether, methyl ethyl ether, methyl chloride, ethyl chloride and the like are preferable from the viewpoint of foamability and foam moldability, and foaming is preferable. Water and carbon dioxide are preferable from the viewpoints of flammability of the agent, flame retardancy of the foam, heat insulating property described later, and the like. Among these, dimethyl ether is particularly preferable from the viewpoint of plasticizing effect, and water is particularly preferable from the viewpoint of cost and the effect of improving heat insulating property by controlling the bubble diameter.

The amount of the foaming agent added in one embodiment of the present invention is preferably 2 to 20 parts by weight, more preferably 2 to 15 parts by weight, based on 100 parts by weight of the styrene resin as a whole. If the amount of the foaming agent added is less than 2 parts by weight, the foaming ratio is low, and it may be difficult to exhibit characteristics such as lightness and heat insulating properties as a resin foam. If it is more than 20 parts by weight, excessive foaming may occur. Due to the amount of the agent, defects such as voids may occur in the foam.

In one embodiment of the present invention, when water and / or alcohols are used as other foaming agents, it is preferable to add a water-absorbent substance in order to stably perform extrusion foam molding. Specific examples of the water-absorbent substance used in one embodiment of the present invention include a polyacrylate-based polymer, a starch-acrylic acid graft copolymer, a polyvinyl alcohol-based polymer, and a vinyl alcohol-acrylate-based copolymer. Water-absorbent polymers such as coalesced, ethylene-vinyl alcohol-based copolymers, acrylonitrile-methyl methacrylate-butadiene-based copolymers, polyethylene oxide-based copolymers and derivatives thereof, as well as anhydrous silica having a silanol group on the surface. (Silicon oxide) [For example, AEROSIL manufactured by Nippon Aerodil Co., Ltd. is commercially available], which is a fine powder having a hydroxyl group on the surface and having a particle diameter of 1000 nm or less; Examples thereof include swellable layered silicates and organically treated products thereof; porous substances such as zeolite, activated carbon, alumina, silica gel, porous glass, activated white clay, diatomaceous soil, and bentonite. The amount of the water-absorbent substance added is appropriately adjusted depending on the amount of water and / or alcohol added, but is preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the styrene resin. 0.1 to 3 parts by weight is more preferable.

In the method for producing a styrene resin extruded foam according to an embodiment of the present invention, the pressure at which the foaming agent is added or injected is not particularly limited, and may be higher than the internal pressure of an extruder or the like. Just do it.

In one embodiment of the present invention, a styrene resin obtained by containing 0.5 parts by weight or more and 5.0 parts by weight or less of a flame retardant with respect to 100 parts by weight of the styrene resin in the styrene resin extruded foam. Flame retardancy can be imparted to the extruded foam. If the content of the flame retardant is less than 0.5 parts by weight, it tends to be difficult to obtain good properties as a foam such as flame retardancy, while if it exceeds 5.0 parts by weight, foam production It may impair the stability and surface properties of the product. However, the content of the flame retardant is determined by the type of foaming agent, the apparent density of the foam, the type of additive having a flame retardant synergistic effect, etc. so that the flame retardancy specified in JIS A9521 measurement method A can be obtained. It is more preferable to adjust appropriately according to the content and the like.

As the flame retardant, a brominated flame retardant is preferably used. Specific examples of the brominated flame retardant in one embodiment of the present invention include hexabromocyclododecane, tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether, and tetrabromobisphenol A-bis. Examples include aliphatic bromine-containing polymers such as (2,3-dibromopropyl) ether, tris (2,3-dibromopropyl) isocyanurate, and brominated styrene-butadiene block copolymers. These may be used alone or in combination of two or more.

Of these, a mixed brominated flame retardant composed of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether and tetrabromobisphenol A-bis (2,3-dibromopropyl) ether, brominated. The styrene-butadiene block copolymer and hexabromocyclododecane are preferably used because they have good extrusion operation and do not adversely affect the heat resistance of the foam. These substances may be used alone or as a mixture.

The content of the bromine-based flame retardant in the styrene-based resin extruded foam according to one embodiment of the present invention is preferably 0.5 parts by weight or more and 5.0 parts by weight or less with respect to 100 parts by weight of the styrene-based resin, and styrene. More preferably 1.0 part by weight or more and 5.0 parts by weight or less, and further preferably 1.5 parts by weight or more and 5.0 parts by weight or less with respect to 100 parts by weight of the based resin. If the content of the brominated flame retardant is less than 0.5 parts by weight, it tends to be difficult to obtain good properties as a foam such as flame retardancy, while if it exceeds 5.0 parts by weight, foaming tends to occur. It may impair the stability and surface properties of the body during manufacturing.

In one embodiment of the present invention, a radical generator can be used in combination for the purpose of improving the flame retardant performance of the styrene resin extruded foam. Specifically, the radical generator is 2,3-dimethyl-2,3-diphenylbutane, poly-1,4-diisopropylbenzene, 2,3-diethyl-2,3-diphenylbutane, 3,4-. Dimethyl-3,4-diphenylhexane, 3,4-diphenyl-3,4-diphenylhexane, 2,4-diphenyl-4-methyl-1-pentene, 2,4-diphenyl-4-ethyl-1-pentene, etc. Can be mentioned. Peroxides such as dicumyl peroxide are also used. Among them, those which are stable under the resin processing temperature conditions are preferable, and specifically, 2,3-dimethyl-2,3-diphenylbutane and poly-1,4-diisopropylbenzene are preferable, and the radical generator of the radical generator. The preferable amount to be added is 0.05 to 0.5 parts by weight with respect to 100 parts by weight of the styrene resin.

Further, for the purpose of improving the flame retardant performance, in other words, as a flame retardant aid, a phosphorus-based flame retardant such as a phosphoric acid ester and a phosphine oxide can be used in combination as long as the thermal stability performance is not impaired. Phosphate esters include triphenyl phosphate, tris (tributylbromoneopentyl) phosphate, tricresyl phosphate, trixylyleneyl phosphate, cresildiphenyl phosphate, 2-ethylhexyldiphenyl phosphate, trimethyl phosphate, triethyl phosphate, tributyl phosphate, Examples thereof include tris (2-ethylhexyl) phosphate, tris (butoxyethyl) phosphate, condensed phosphate ester and the like, and triphenyl phosphate or tris (tributylbromoneopentyl) phosphate is particularly preferable. Further, as the phosphine oxide type phosphorus flame retardant, triphenylphosphine oxide is preferable. These phosphate esters and phosphine oxides may be used alone or in combination of two or more. The preferable amount of the phosphorus-based flame retardant added is 0.1 to 2 parts by weight with respect to 100 parts by weight of the styrene-based resin.

In one embodiment of the present invention, a resin and / or a flame retardant stabilizer can be used, if necessary. Specific examples of the stabilizer include, but are not limited to, (i) bisphenol A diglycidyl ether type epoxy resin, cresol novolac type epoxy resin, and epoxy compounds such as phenol novolac type epoxy resin, ( ii) A reaction product of a polyhydric alcohol such as pentaerythritol, dipentaerythritol or tripentaerythritol with a monovalent carboxylic acid such as acetic acid or propionic acid or a divalent carboxylic acid such as adipic acid or glutamate. A polyhydric alcohol ester, (iii) triethylene glycol-bis-3-, which is an ester, which is a mixture of esters having one or more hydroxyl groups in its molecule and may contain a small amount of the raw material polyhydric alcohol. (3-tert-Butyl-4-hydroxy-5-methylphenyl) propionate, pentaerythritol tetrakis [3- (3', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate], and octadecyl 3- Phenolic stabilizers such as (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, (iv) 3,9-bis (2,4-di-tert-butylphenoxy) -2,4 8,10-Tetraoxa-3,9-diphosphaspiro [5.5] undecane, 3,9-bis (2,6-di-tert-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa- Phosphite-based stabilizers, such as 3,9-diphosphaspiro [5.5] undecane, and tetrakis (2,4-di-tert-butyl-5-methylphenyl) -4,4'-biphenylenediphosphonite). Etc. are preferably used because they do not deteriorate the flame retardant performance of the foam and improve the thermal stability of the foam.

The styrene resin extruded foam according to the embodiment of the present invention may contain graphite as a heat ray radiation inhibitor in order to improve heat insulating properties. Examples of graphite used in one embodiment of the present invention include scale (piece) graphite, earth-like graphite, spheroidal graphite, and artificial graphite. Among these, it is preferable to use scaly graphite as the main component because it has a high effect of suppressing heat ray radiation. Graphite preferably has a fixed carbon content of 80% or more, and more preferably 85% or more. By setting the fixed carbon content in the above range, a foam having high heat insulating properties can be obtained.

The average particle size of graphite is preferably 15 μm or less, more preferably 10 μm or less. By setting the average particle size in the above range, the specific surface area of graphite is increased and the probability of collision with heat ray radiation is increased, so that the effect of suppressing heat ray radiation is enhanced. The average particle size is the particle size when the particle size distribution is measured and analyzed by the laser diffraction scattering method based on the Mie theory based on ISO13320: 2009 and JIS Z8825: 2013, and the cumulative volume with respect to the volume of all particles becomes 50%. It means (volume average particle size by laser diffraction scattering method).

The graphite content in one embodiment of the present invention is preferably 1.0 part by weight or more and 5.0 parts by weight or less, and 1.5 parts by weight or more and 3.0 parts by weight or less with respect to 100 parts by weight of the styrene resin. More preferred. If the content is less than 1.0 part by weight, a sufficient effect of suppressing heat ray radiation cannot be obtained. If the content exceeds 5.0 parts by weight, the effect of suppressing heat ray radiation corresponding to the content cannot be obtained, and there is no cost merit.

The heat ray radiation inhibitor refers to a substance having a property of reflecting, scattering, and absorbing light in the near infrared or infrared region. By containing a heat ray radiation inhibitor, a foam having high heat insulating properties can be obtained. As the heat ray radiation inhibitor that can be used in one embodiment of the present invention, white particles such as titanium oxide, barium sulfate, zinc oxide, aluminum oxide, and antimony oxide can be used in combination with graphite. These may be used alone or in combination of two or more. Among these, titanium oxide or barium sulfate is preferable, and titanium oxide is more preferable, because the effect of suppressing radiation radiation is large. The average particle size of the white particles is not particularly limited, but considering the effective reflection of infrared rays and the color-developing property of the resin, for example, for titanium oxide, 0.1 μm to 10 μm is preferable. , 0.15 μm to 5 μm is more preferable.

The content of the white particles in one embodiment of the present invention is preferably 1.0 part by weight or more and 3.0 parts by weight or less, and 1.5 parts by weight or more and 2.5 parts by weight, based on 100 parts by weight of the styrene resin. More preferably, it is by weight or less. The white particles have a smaller heat ray radiation suppressing effect than graphite, and when the content of the white particles is less than 1.0 part by weight, there is almost no heat ray radiation suppressing effect even if the white particles are contained. When the content of the white particles exceeds 3.0 parts by weight, the heat ray radiation suppressing effect corresponding to the content cannot be obtained, while the flame retardancy of the foam tends to deteriorate.

The total content of the heat ray radiation inhibitor in one embodiment of the present invention is preferably 1.0 part by weight or more and 6.0 parts by weight or less, and 2.0 parts by weight or more and 5. More preferably, it is 0 parts by weight or less. If the total content of the heat ray radiation inhibitor is less than 1.0 part by weight, it is difficult to obtain heat insulating properties. On the other hand, as the content of the solid additive such as the heat ray radiation inhibitor increases, the number of nucleation points increases. In addition, it tends to be difficult to give the extruded foam a beautiful surface and to increase the thickness of the extruded foam because the bubbles in the foam become finer and the elongation of the resin itself deteriorates. When the total content of the heat ray radiation inhibitor exceeds 6.0 parts by weight, it tends to be inferior, in particular, to impart a beautiful surface to the extruded foam and to increase the thickness of the extruded foam. It tends to impair extrusion stability and flame retardancy.

In one embodiment of the present invention, if necessary, for example, silica, calcium silicate, wallastnite, kaolin, clay, mica, carbonic acid, as long as the effects according to the embodiment of the present invention are not impaired. Inorganic compounds such as calcium, sodium stearate, calcium stearate, magnesium stearate, barium stearate, liquid paraffin, olefin wax, processing aids such as stearylamide compounds, phenolic antioxidants, phosphorus stabilizers, nitrogen Additives such as system stabilizers, sulfur stabilizers, light-resistant stabilizers such as benzotriazoles and hindered amines, bubble size adjusters such as talc, flame retardants other than the above, antistatic agents, and colorants such as pigments It may be contained in a styrene resin.

The method and procedure for blending various additives with the styrene resin include, for example, a method of adding various additives to the styrene resin and mixing them by dry blending, and melting from a supply section provided in the middle of the extruder. A method of adding various additives to a styrene resin, using an extruder, kneader, Banbury mixer, roll, etc. in advance to prepare a masterbatch containing various additives at a high concentration in the styrene resin, and using the masterbatch Examples thereof include a method of mixing the styrene resin with a dry blend, and a method of supplying various additives to the extruder by a supply facility different from the styrene resin. For example, there is a procedure in which various additives are added to a styrene resin and mixed, then supplied to an extruder, heated and melted, and then a foaming agent is added and mixed. Various additives or foaming agents The timing and kneading time of adding the styrene resin to the styrene resin are not particularly limited.

The thermal conductivity of the styrene-based resin extruded foam according to one embodiment of the present invention is not particularly limited, but it is considered that it functions as, for example, a heat insulating material for construction or a heat insulating material for a cold storage or a cold storage vehicle. From the viewpoint of heat insulating properties, the thermal conductivity one week after production measured at an average temperature of 23 ° C. is preferably 0.0284 W / mK or less, more preferably 0.0244 W / mK or less, and 0.0224 W. It is particularly preferable that it is / mK or less.

The apparent density of the styrene-based resin extruded foam according to one embodiment of the present invention is, for example, heat insulating and lightweight in consideration of functioning as a heat insulating material for a building or a heat insulating material for a cold storage or a cold storage vehicle. From the viewpoint, ^{it is preferably 20 kg / m 3} or more and 60 kg / m ³ or less, and more preferably 25 kg / m ³ or more and 45 kg / m ³ or less.

The closed cell ratio of the styrene resin extruded foam according to one embodiment of the present invention is preferably 80% or more, more preferably 90% or more. If the closed cell ratio is less than 80%, the foaming agent is dissipated from the extruded foam at an early stage, and the heat insulating property is lowered.

The average cell diameter in the thickness direction of the styrene resin extruded foam according to the embodiment of the present invention is preferably 0.05 mm or more and 0.5 mm or less, more preferably 0.05 mm or more and 0.4 mm or less, and more preferably 0.05 mm or more. 0.3 mm or less is particularly preferable. In general, the smaller the average cell diameter, the shorter the distance between the cell walls of the foam, so the range of motion of the bubbles in the extruded foam when giving shape to the extruded foam during extrusion foaming is narrow, and deformation is difficult. Therefore, it tends to be difficult to impart a beautiful surface to the extruded foam and to increase the thickness of the extruded foam. When the average cell diameter in the thickness direction of the styrene resin extruded foam is smaller than 0.05 mm, it tends to be particularly difficult to impart a beautiful surface to the extruded foam and to obtain the thickness of the extruded foam. It becomes a thing. On the other hand, if the average cell diameter in the thickness direction of the styrene resin extruded foam exceeds 0.5 mm, sufficient heat insulating properties may not be obtained.

The average cell diameter of the styrene resin extruded foam according to one embodiment of the present invention was evaluated using a microscope [DIGITAL MICROSCOPE VHX-900, manufactured by KEYENCE Co., Ltd.] as described below.

Width direction vertical cross section of the obtained styrene resin extruded foam at a total of three locations, one at the center in the width direction and 150 mm from one end in the width direction to the opposite end (the same location at both ends in the width direction). Was observed with the microscope from the extrusion direction and the width direction, and a 100-fold magnified photograph was taken. Arbitrarily draw three 2 mm straight lines in the thickness direction of the enlarged photograph (three at each observation point and each observation direction), measure the number of bubbles a in contact with the straight lines, and measure the number of bubbles a from the measured number of bubbles a. The average bubble diameter A in the thickness direction for each observation point was obtained by the following equation (1). The average value of the three locations (two directions at each location) was defined as the average cell diameter A (average value) in the thickness direction of the styrene resin extruded foam.

Average bubble diameter A (mm) in the thickness direction for each observation point = 2 × 3 / number of bubbles a
... (1)
Extruded vertical cross section of the obtained styrene-based resin extruded foam at a total of three locations, one at the center in the width direction and 150 mm from one end in the width direction to the opposite end (the same location at both ends in the width direction). Was observed from the width direction with the microscope, and a 100-fold magnified photograph was taken. Arbitrarily draw three 2 mm straight lines in the extrusion direction of the enlarged photograph (three for each observation point), measure the number b of bubbles in contact with the straight lines, and from the measured number of bubbles b, the following equation (2) ) Was used to determine the average cell diameter B in the extrusion direction for each observation location. The average value of the three locations was taken as the average cell diameter B (average value) in the extrusion direction of the styrene resin extruded foam.

Average bubble diameter B (mm) in extrusion direction for each observation point = 2 × 3 / number of bubbles b
... (2)
Width vertical cross section of the obtained styrene resin extruded foam at a total of three locations, one at the center in the width direction and 150 mm from one end in the width direction to the opposite end (the same location at both ends in the width direction). Was observed with the microscope from the extrusion direction, and a 100-fold magnified photograph was taken. Arbitrarily draw three 2 mm straight lines in the width direction of the enlarged photograph (three for each observation point), measure the number c of bubbles in contact with the straight lines, and obtain the following equation (3) from the measured number of bubbles c. ) Was used to determine the average bubble diameter C in the width direction for each observation location. The average value of the three locations was defined as the average cell diameter C (average value) in the width direction of the styrene resin extruded foam.

Average bubble diameter C (mm) in the width direction for each observation point = 2 × 3 / number of bubbles c
... (3)
The bubble deformation rate of the styrene resin extruded foam according to one embodiment of the present invention is preferably 0.7 or more and 2.0 or less, more preferably 0.8 or more and 1.5 or less, and 0.8 or more and 1.2. The following is more preferable. If the bubble deformation rate is smaller than 0.7, the compressive strength becomes low, and there is a risk that the strength suitable for the application cannot be secured in the extruded foam. Further, since the bubbles tend to return to a spherical shape, the size (shape) maintainability of the extruded foam tends to be inferior. On the other hand, when the bubble deformation rate exceeds 2.0, the number of bubbles in the thickness direction of the extruded foam is reduced, so that the effect of improving the heat insulating property due to the bubble shape is reduced.

The bubble deformation rate of the styrene resin extruded foam according to the embodiment of the present invention can be obtained from the above-mentioned average cell diameter by the following formula (4).

Bubble deformation rate (no unit) = A (average value) / {[B (average value) + C (average value)] / 2} ... (4)
The thickness of the styrene resin extruded foam according to the embodiment of the present invention is heat insulating property, bending strength and compressive strength in consideration of functioning as, for example, a heat insulating material for construction or a heat insulating material for a cold storage or a cold storage vehicle. From the above viewpoint, it is preferably 10 mm or more and 150 mm or less, more preferably 20 mm or more and 130 mm or less, and particularly preferably 30 mm or more and 120 mm or less.

In the styrene resin extruded foam, as described in Examples and Comparative Examples of the present invention, after extruding and foam molding to give a shape, both surfaces of a plane perpendicular to the thickness direction are unilaterally sided in the thickness direction. The product may be cut to a depth of about 5 mm to obtain the product thickness, but unless otherwise specified, the thickness of the styrene resin extruded foam according to one embodiment of the present invention is extruded and foamed to give a shape. It is the uncut thickness as it is.

The shape of the styrene resin extruded foam according to one embodiment of the present invention is the extrusion direction, the width direction, and the thickness so as to be suitably used as, for example, a heat insulating material for construction or a heat insulating material for a cold storage or a cold storage vehicle. It must be plate-shaped with no waviness in any direction. As described above, for example, when a hydrofluoroolefin is used, when a heat ray radiation inhibitor is used, or when the average cell system becomes finer as a styrene-based extruded foam, the elongation of the resin itself deteriorates. Or, when the extruded foam is extruded and foamed to give a shape, the movable range of the bubbles of the extruded foam is narrow and it is difficult to deform. However, the extruded foam may not be plate-shaped because it is wavy in any one or more of the extrusion direction, the width direction, and the thickness direction.

The surface property of the styrene resin extruded foam according to the embodiment of the present invention is used as a product in order to ensure stability during production and when both surfaces of a plane perpendicular to the thickness direction are left. Since it is particularly important, it must be clean with no flow marks, cracks, or lumps. As described above, for example, when a hydrofluoroolefin is used, when a heat ray radiation inhibitor is used, or when the average cell system becomes finer as a styrene-based extruded foam, the elongation of the resin itself deteriorates. Or, when the extruded foam is extruded to give a shape, the movable range of the bubbles of the extruded foam is narrow and it is difficult to deform, so that flow marks, cracks, swelling, etc. occur on the surface of the extruded foam. The surface property may be impaired. The flow mark is a flow mark of the molten resin, and is generated on both surfaces of a plane perpendicular to the thickness direction when the resin itself is hard and does not stretch well. Cracks are cracks that occur when an excessive force is applied to the extruded foam, and are particularly likely to occur when the extruded foam is forcibly molded to increase its thickness while it is difficult to obtain the thickness. .. It may occur on both surfaces of a plane perpendicular to the thickness direction, or it may occur at the edge (side) in the width direction. In severe cases, cracks may be the starting point and the continuously produced extruded foam may be torn. In addition, worming is when a part of the foamed molten resin is over-solidified and is caught in the molding die and rolled up, so that both surfaces of the plane perpendicular to the thickness direction and / or the edge in the width direction are formed. It may occur locally or globally (on the side).

In the present specification, the styrene resin extruded foam may be referred to as moldability including thickness-adding property, shape-imparting property, and surface property at the time of foam molding.

Thus, according to one embodiment of the present invention, it is possible to easily obtain a styrene-based resin extruded foam having excellent heat insulating properties, a beautiful appearance, and a sufficient thickness suitable for use.

[2. Method for manufacturing styrene resin extruded foam]
The method for producing the styrene resin extruded foam according to the embodiment of the present invention is described in [1. Styrene-based resin extruded foam] is a production method used for producing the styrene-based resin extruded foam. Among the configurations used in the method for producing a styrene resin extruded foam according to an embodiment of the present invention, [1. The configuration already described in [Styrene-based resin extruded foam] will be omitted here.

As a method for producing the styrene resin extruded foam according to the embodiment of the present invention, a styrene resin, a polyethylene glycol masterbatch, and, if necessary, a flame retardant, a stabilizer, a heat ray radiation inhibitor, or other Additives and the like are supplied to the heating and melting part of the extruder and the like. At this time, the foaming agent can be added to the styrene resin under high pressure conditions at any stage. Then, a mixture of a styrene resin, a polyethylene glycol masterbatch, a foaming agent, and other additives is formed as a fluidized gel, cooled to a temperature suitable for extrusion foaming, and then the fluidized gel is extruded and foamed into a low pressure region through a die. , Form foam.

The heating temperature in the heating and melting section may be higher than the temperature at which the styrene-based resin used melts, but the temperature at which molecular deterioration of the resin due to the influence of additives or the like is suppressed as much as possible, for example, 150 ° C. to 260 ° C. Degree is preferred. The melt-kneading time in the heat-melting section is uniquely defined because it differs depending on the extrusion amount of the styrene resin per unit time and / or the type of extruder used as the heat-melting section and used as the melt-kneading section. This is not possible, and the time required for the styrene resin, the foaming agent, and the additive to be uniformly dispersed and mixed is appropriately set.

Examples of the melt-kneaded portion include a screw type extruder, but the melt-kneaded portion is not particularly limited as long as it is used for ordinary extrusion foaming.

The foam molding method according to an embodiment of the present invention is, for example, an extruded foam obtained by opening from a high pressure region to a low pressure region through a slit die having a straight slit shape at an opening used for extrusion molding. A method of molding a plate-shaped foam having a large cross-sectional area using a molding die installed in close contact with or in contact with a slit die, a molding roll installed adjacent to the downstream side of the molding die, or the like. Is used. By adjusting the flow surface shape of the molding die and adjusting the temperature of the die, the desired cross-sectional shape of the foam, the surface property of the foam, and the quality of the foam can be obtained.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

Hereinafter, examples of the present invention will be described. Needless to say, the present invention is not limited to the following examples.

The raw materials used in Examples and Comparative Examples are as follows.

○ Base resin / Styrene resin [PS Japan Corporation, G9401; MFR 2.2 g / 10 minutes]
○ Heat ray radiation inhibitor ・ Graphite [M-885 manufactured by Marutoyo Casting Co., Ltd.; Scale (piece) graphite, average particle size 5.5 μm, fixed carbon content 89%]
-Titanium oxide [manufactured by Sakai Chemical Industry Co., Ltd., R-7E; average particle size 0.23 μm]
○ Flame retardant ・ Mixed brominated flame retardant of tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether and tetrabromobisphenol A-bis (2,3-dibromopropyl) ether [Daiichi Kogyo Made by Pharmaceutical Co., Ltd., GR-125P]
○ Flame-retardant aid / triphenylphosphine oxide [Sumitomo Shoji Chemical]
○ Stabilizer ・ Bisphenol-A-glycidyl ether [manufactured by ADEKA Corporation, EP-13]
・ Dipentaerythritol-adipic acid reaction mixture [Ajinomoto Fine-Techno Co., Ltd., Plenizer ST210]
-Triethylene glycol-bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate [Songwon Japan Co., Ltd., Sonnox 2450FF]
○ Other additives ・ Talc [Talc powder PK-Z manufactured by Hayashi Kasei Co., Ltd.]
・ Calcium stearate [Sakai Chemical Industry Co., Ltd., SCP]
・ Bentonite [Made by Hojun Co., Ltd., Wenger Bright 11K]
・ Silica [Carplex BS-304F, manufactured by Evonik Degussa Japan Co., Ltd.]
-Ethylene bisstearic acid amide [manufactured by NOF CORPORATION, Alflo H-50S]
○ Moldability improver ・ PEG 6000 [manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., PEG 6000; average molecular weight 7400 to 9000, freezing point 56 to 61 ° C]
○ Foaming agent, HFO-1234ze [Manufactured by Honeywell Japan Co., Ltd.]
・ HCFO-1233zd [Manufactured by Honeywell Japan Co., Ltd.]
・ Dimethyl ether [manufactured by Iwatani Corporation]
・ Isobutane [manufactured by Mitsui Chemicals, Inc.]
・ Water [Tap water in Settsu City, Osaka Prefecture].

The production stability of the production conditions of Examples and Comparative Examples was evaluated according to the following viewpoints.

(1) Retention rate of discharge amount The retention rate of the discharge amount after a lapse of a predetermined time from the start of supply of the predetermined resin mixture to the extruder (hereinafter, also referred to as "at the start of supply") is calculated as follows. It was calculated by the formula (5) and judged by the following evaluation criteria.

Discharge rate retention rate (%) = Q (kg / h) / Q ₀ (kg / h) x 100 ... (5)
Here, Q (kg / h) is the discharge amount after a lapse of a predetermined time, and Q ₀ (kg / h) is the discharge amount at the start of supply.
◯: The retention rate of the discharge amount after 12 hours or more from the start of supply is 70% or more.
X: The retention rate of the discharge amount after 12 hours or more from the start of supply is less than 70%.

Further, regarding the physical properties of the extruded foams according to Examples and Comparative Examples, the thickness (before cutting), apparent density, closed cell ratio, average cell diameter, bubble deformation rate, and thermal conductivity of the styrene resin extruded foam according to the following method. The rate, JIS flammability, and foam appearance were evaluated.

(2) Thickness of styrene resin extruded foam (before cutting)
Using a caliper [Mitutoyo Co., Ltd., M-type standard caliper N30], the thickness at the center in the width direction and 150 mm from one end in the width direction to the opposite end (the same place at both ends in the width direction), a total of 3 points Was measured. The average value of the three points was taken as the thickness of the styrene resin extruded foam.

(3) Apparent density (kg / m ³ )
The weight of the obtained styrene-based resin extruded foam was measured, and the length, width, and thickness were measured.

From the measured weight and each dimension, the foam density was obtained based on the following formula (6), and the unit was converted to ^{kg / m 3.}
Apparent density (g / cm ³ ) = foam weight (g) / foam volume (cm ³ ) ... (6)
(4) Closed cell ratio The thickness of the obtained styrene resin extruded foam is 40 mm from a total of three locations, 150 mm in the width direction from one end to the opposite end (the same location for both ends in the width direction). Using a test piece cut out to have a length (extrusion direction) of 25 mm and a width of 25 mm, measurement was performed according to procedure C of ASTM-D2856-70, and the closed cell ratio of each test piece was calculated by the following formula (7). The average value of the three locations was taken as the closed cell ratio of the styrene resin extruded foam.
Closed cell ratio (%) = (V1-W / ρ) × 100 / (V2-W / ρ) ... (7)
Here, V1 (cm ³ ) is the true volume of the test piece (volume of the non-closed cell portion) measured using an air comparison hydrometer [Tokyo Science Co., Ltd., air comparison hydrometer, model 1000]. Is excluded.). V2 (cm ³ ) is an apparent volume calculated from the outer dimensions of the test piece measured using a caliper [Mitutoyo Co., Ltd., M-type standard caliper N30]. W (g) is the total weight of the test piece. Further, ρ (g / cm ³ ) is the density of the styrene-based resin constituting the extruded foam, and was set to 1.05 (g / cm ³ ).

(5) Average cell diameter and bubble deformation rate in the thickness direction The obtained styrene-based resin extruded foam was evaluated as described above.

(6) Thermal conductivity According to JIS A 9521, using a test piece cut out to a thickness of product thickness x length (extrusion direction) 300 mm x width 300 mm, a thermal conductivity measuring device [Eiko Seiki Co., Ltd., HC- 074] measured the thermal conductivity at an average temperature of 23 ° C. For the measurement, after the styrene resin extruded foam is manufactured, it is cut into a test piece of the above dimensions, and the standard temperature state 3 (23 ° C ± 5 ° C) and the standard humidity 3 (50 ° C) specified in JIS K 7100 are measured. ^+20, -. ^10% R.H) was allowed to stand under the conditions of, was performed from the production after 1 week.

(7) JIS flammability According to JIS A 9521, a test piece having a thickness of 10 mm × a length of 200 mm × a width of 25 mm was used and evaluated according to the following criteria. For the measurement, after the styrene resin extruded foam is manufactured, it is cut into a test piece of the above dimensions, and the standard temperature state 3 (23 ° C ± 5 ° C) and the standard humidity 3 (50 ° C) specified in JIS K 7100 are measured. ^It was allowed to stand under the conditions of +20, ^-10 % RH), and was carried out one week after the production.
◯: Satisfies the criteria that the flame is extinguished within 3 seconds, there is no residue, and the combustion does not exceed the combustion limit indicator line.
X: Does not meet the above criteria.

(8) Appearance of foam From the evaluation results of shape and surface properties described in (8) -1 and (8) -2 below, the determination was made according to the following evaluation criteria.
Passed: Both the shape and surface quality evaluation results are ○.
Fail: At least one of the evaluation results of shape and surface property is Δ or ×.

(8) -1. Shape The extruded foam after the molding roll and before cutting was visually inspected and evaluated according to the following evaluation criteria.
◯: The extruded foam has a plate shape without waviness in any of the extrusion direction, the width direction, and the thickness direction.
X: The extruded foam is wavy in one or more of the extrusion direction, the width direction, and the thickness direction, and is not plate-shaped.

(8) -2. The extruded foam before and after the surface cut was visually inspected and evaluated according to the following evaluation criteria. The surface refers to a surface perpendicular to the thickness direction, and after cutting, both surfaces are cut at a depth of 5 mm on one side in the thickness direction based on the thickness of the styrene resin extruded foam (mean value at 3 points). Refers to the state.
◯: The surface is beautiful with no surface abnormalities such as flow marks, cracks, and lumps.
Δ: There are surface abnormalities such as flow marks, cracks, and burrs, but these marks do not remain on the surface after cutting.
X: There are surface abnormalities such as flow marks, cracks, and burrs, and these marks remain on the surface after cutting.

For Examples and Comparative Examples, graphite, titanium oxide and polyethylene glycol were added by a masterbatch prepared according to the following procedure.

[Making a graphite masterbatch]
In a Banbury mixer, 100 parts by weight of styrene resin [PS Japan Co., Ltd., G9401], which is a base resin, and 100 parts by weight of styrene resin, graphite [manufactured by Marutoyo Casting Co., Ltd., M-885] 102 parts by weight and ethylene bisstearic acid amide [manufactured by Nichiyu Co., Ltd., Alflo H-50S] 2.0 parts by weight are added and heated and cooled under a load of ^{5 kgf / cm 2.} Was melt-kneaded for 20 minutes without performing. At this time, the resin temperature was measured and found to be 190 ° C. A strand-shaped resin supplied to a ruder and extruded at a discharge rate of 250 kg / hr through a die having a small hole attached to the tip was cooled and solidified in a water tank at 30 ° C., and then cut to obtain a masterbatch.

[Making a titanium oxide masterbatch]
In the Banbury mixer, 100 parts by weight of styrene resin [PS Japan Corporation, G9401], which is the base resin, and 100 parts by weight of styrene resin, titanium oxide [manufactured by Sakai Chemical Industry Co., Ltd., R. -7E] 154 parts by weight and ethylene bisstearic acid amide [manufactured by Nichiyu Co., Ltd., Alflo H-50S] 2.6 parts by weight were added and heated and cooled under a load of ^{5 kgf / cm 2.} The mixture was melt-kneaded for 20 minutes without any action. At this time, the resin temperature was measured and found to be 190 ° C. A strand-shaped resin supplied to a ruder and extruded at a discharge rate of 250 kg / hr through a die having a small hole attached to the tip was cooled and solidified in a water tank at 30 ° C., and then cut to obtain a masterbatch.

[Preparation of polyethylene glycol masterbatch A]
Using separate supply feeders for a biaxial extruder with a diameter of 37 mm in the same direction, 100 parts by weight of styrene resin [PS Japan Co., Ltd., G9401] and 100 parts by weight of styrene resin, which are the base resin. 2.56 parts by weight of polyethylene glycol [made by Daiichi Kogyo Seiyaku Co., Ltd., PEG6000] was supplied so that the total amount of the styrene resin and polyethylene glycol was 50 kg / hr.

The mixture of styrene resin and polyethylene glycol supplied to the twin-screw extruder is heated to 200 ° C., melted and kneaded at a screw rotation speed of 200 rpm, and discharged through a die having a small hole attached to the tip of the twin-screw extruder. The strand-shaped resin extruded at an amount of 50 kg / hr was cooled and solidified in a water tank at 30 ° C., and then cut to obtain a masterbatch. The resin temperature measured in the die portion was 220 ° C.

[Preparation of polyethylene glycol masterbatch B]
Using separate supply feeders for a biaxial extruder with a diameter of 37 mm in the same direction, 100 parts by weight of styrene resin [PS Japan Co., Ltd., G9401] and 100 parts by weight of styrene resin, which are the base resin. 25 parts by weight of polyethylene glycol [made by Daiichi Kogyo Seiyaku Co., Ltd., PEG6000] was supplied so that the total amount of the styrene resin and polyethylene glycol was 50 kg / hr.

A mixture of styrene resin and polyethylene glycol supplied to a twin-screw extruder with a diameter of 37 mm is heated to 200 ° C., melted and kneaded at a screw rotation speed of 200 rpm, and a small hole attached to the tip of the twin-screw extruder. A strand-shaped resin extruded at a discharge rate of 50 kg / hr was cooled and solidified in a water tank at 30 ° C., and then cut to obtain a masterbatch. The resin temperature measured in the die portion was 218 ° C.

[Preparation of polyethylene glycol masterbatch C]
A liquid that can be heated after supplying 100 parts by weight of a styrene resin [PS Japan Corporation, G9401], which is a base resin, to a same-direction twin-screw extruder having a diameter of 37 mm and heating it to 200 ° C. to melt it. 11.1 parts by weight of polyethylene glycol [made by Dai-ichi Kogyo Seiyaku Co., Ltd., PEG6000], which was heated to 100 ° C. in an addition facility to make it liquid, was added from the middle of the extruder. At this time, the total amount of the styrene resin and the polyethylene glycol was supplied so as to be 50 kg / hr. After that, the mixture of styrene resin and polyethylene glycol is heated to 200 ° C. in a twin-screw extruder, melted and kneaded at a screw rotation speed of 200 rpm, and discharged at a discharge rate of 50 kg / hr through a die having a small hole attached to the tip. The extruded strand-shaped resin was cooled and solidified in a water tank at 30 ° C., and then cut to obtain a masterbatch. The resin temperature measured in the die portion was 217 ° C.

[Preparation of polyethylene glycol masterbatch D]
A liquid that can be heated after supplying 100 parts by weight of a styrene resin [PS Japan Corporation, G9401], which is a base resin, to a same-direction twin-screw extruder having a diameter of 37 mm and heating it to 200 ° C. to melt it. 25.0 parts by weight of polyethylene glycol [made by Daiichi Kogyo Seiyaku Co., Ltd., PEG6000], which was heated to 100 ° C. in an addition facility and liquefied, was added from the middle of the extruder. At this time, the total amount of the styrene resin and the polyethylene glycol was supplied so as to be 50 kg / hr. After that, the mixture of styrene resin and polyethylene glycol is heated to 200 ° C. in a twin-screw extruder, melted and kneaded at a screw rotation speed of 200 rpm, and discharged at a discharge rate of 50 kg / hr through a die having a small hole attached to the tip. The extruded strand-shaped resin was cooled and solidified in a water tank at 30 ° C., and then cut to obtain a masterbatch. The resin temperature measured in the die portion was 215 ° C.

(Example 1)
[Preparation of resin mixture]
92.8 parts by weight of styrene resin [PS Japan Co., Ltd., G9401] which is a base resin, 5.0 parts by weight of graphite master batch as a heat ray radiation inhibitor, and 2.5 parts by weight of titanium oxide master batch. , Tetrabromobisphenol A-bis (2,3-dibromo-2-methylpropyl) ether as a flame retardant and tetrabromobisphenol A-bis (2,3-dibromopropyl) ether mixed brominated flame retardant [1st Industrial Pharmaceutical Co., Ltd., GR-125P] 3.0 parts by weight, triphenylphosphin oxide as a flame retardant auxiliary agent [Sumitomo Shoji Chemical] 1.0 part by weight, talc [Hayashi Kasei Co., Ltd.] , Talcan powder PK-Z] 0.5 parts by weight, bisphenol-A-glycidyl ether as a stabilizer [manufactured by ADEKA Co., Ltd., EP-13] 0.20 parts by weight, triethylene glycol-bis-3- (3-) t-Butyl-4-hydroxy-5-methylphenyl) propionate [Songwon Japan Co., Ltd., Sonnox 2450FF] 0.20 parts by weight, dipentaerythritol-adipic acid reaction mixture [Ajinomoto Fine Techno, Plenizer ST210] 0.10 parts by weight, calcium stearate [manufactured by Sakai Chemical Industry Co., Ltd., SC-P] 0.20 parts by weight as a lubricant, bentonite [manufactured by Hojun Co., Ltd., Bengel Bright 11K] 0.40 parts by weight as a water absorption medium, 0.40 parts by weight of silica [Carplex BS-304F manufactured by Ebonic Degusa Japan Co., Ltd.] and 4.0 parts by weight of Polyethylene Glycol Master Batch B as a moldability improver were dry blended. As described above, graphite, titanium oxide, and polyethylene glycol were added in advance as a masterbatch of styrene-based resin at the time of preparation of the resin mixture. When the masterbatch was used, the base resin was 100 parts by weight in total with the base resin contained in the masterbatch.

[Preparation of extruded foam]
The obtained resin mixture is transferred to an extruder having a diameter of 150 mm (first extruder), a single screw extruder having a diameter of 200 mm (second extruder), and a cooler connected in series at 950 kg / hr. Supplied in. The screw rotation speed of the first extruder was adjusted so that the discharge amount was 950 kg / hr at the start of supply of the resin mixture, and was kept constant without being adjusted even after a predetermined time had elapsed.

The resin mixture supplied to the first extruder is heated to a resin temperature of 240 ° C. to melt, plasticize, and knead, and a foaming agent (3.5 parts by weight of isobutane and dimethyl ether with respect to 100 parts by weight of the base resin). 5 parts by weight and 0.7 parts by weight of water (tap water)) were press-fitted into the resin near the tip of the first extruder.

After that, the resin temperature was cooled to 120 ° C. in the second extruder and the cooler connected to the first extruder, and a base (slit die) having a rectangular cross section with a thickness of 6 mm and a width of 400 mm was provided at the tip of the cooler. ), After extruding and foaming into the atmosphere at a foaming pressure of 3.0 MPa, a molding die installed in close contact with the mouthpiece and a molding roll installed on the downstream side thereof have a cross-sectional shape of 60 mm in thickness and 1000 mm in width. An extruded foam plate was obtained and cut into a thickness of 50 mm, a width of 910 mm and a length of 1820 mm with a cutter. Table 1 shows the discharge amount of the obtained foam and the evaluation results.

(Examples 2 to 8)
As shown in Table 1, an extruded foam was obtained by the same operation as in Example 1 except that the types of various formulations, the amount of addition, and / or the production conditions were changed. Table 1 shows the physical characteristics of the obtained extruded foam.

(Comparative Examples 1 to 7)
As shown in Table 2, an extruded foam was obtained by the same operation as in Example 1 except that the types of various formulations, the amount of addition, and / or the production conditions were changed. Table 2 shows the physical characteristics of the obtained extruded foam.

As can be seen from Examples 1 to 8, the appearance is beautiful and suitable for use by including the step of adding the masterbatch in which the content of the styrene resin and the content of polyethylene glycol are within the range of the present patent. A styrene-based extruded foam having a sufficient thickness and a thermal conductivity of 0.022 to 0.024 W / mK, which has excellent heat insulating properties, has a retention rate of a discharge amount 12 hours after the start of supply. It can be continuously and stably produced at 97 to 101%.

As can be seen by comparing Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 7 and Comparative Example 3, in each Comparative Example to which polyethylene glycol is not added, 12 hours have passed since the start of supply. The retention rate of the discharge amount is 98 to 100%, which is not a problem, but the appearance of the obtained styrene-based resin extruded foam is inferior. On the other hand, in each example to which polyethylene glycol was added, a styrene resin extruded foam having an excellent foam appearance can be obtained.

As can be seen by comparing Example 1 and Comparative Example 4, Examples 2 and 3 and Comparative Examples 5 to 6, and Example 7 and Comparative Example 7, polyethylene glycol was not used as a masterbatch regardless of the blending of the foaming agent. In each of the comparative examples added as they were, the retention rate of the discharge amount 12 hours after the start of supply was as low as 35 to 37%, and when the discharge amount was low, the thermal conductivity of the obtained styrene resin extruded foam was low. Since the rate and the appearance of the foam deteriorate, it is not possible to continuously and stably produce the styrene resin extruded foam. On the other hand, in each example in which polyethylene glycol was added as a masterbatch with a styrene resin, the retention rate of the discharge amount 12 hours after the start of supply was as high as 97 to 100%, and the foam had a sufficient thickness of 60 mm. A styrene-based extruded foam having an excellent appearance and a thermal conductivity of 0.022 to 0.024 W / mK and excellent heat insulating properties can be continuously and stably produced.

As can be seen from Examples 3 and 6, by using a masterbatch in which the content of the styrene resin and the content of polyethylene glycol are within the scope of the present patent, 12 hours have passed since the start of supply. A styrene-based extruded foam having a high retention rate of 98 to 100% and a sufficient thickness of 60 mm and an excellent appearance of the foam can be continuously and stably produced.

As can be seen from Examples 2 and 3, by setting the amount of polyethylene glycol added within the scope of the present patent, it is possible to obtain a styrene-based extruded foam having a sufficient thickness of 60 mm and an excellent foam appearance.

As can be seen from Examples 3 to 5, by using polyethylene glycol having an average molecular weight within the range of the present patent, a styrene-based extruded foam having a sufficient thickness of 60 mm and an excellent foam appearance can be obtained.

As a whole, from Examples 1 to 8, it has excellent heat insulating properties by including the step of adding the masterbatch in which the content of the styrene resin and the content of polyethylene glycol are within the range of the present patent. Further, it can be seen that a styrene-based resin extruded foam having a beautiful surface and a sufficient thickness suitable for use can be easily and continuously and stably produced.

According to the present invention, a styrene-based resin extruded foam having excellent heat insulating properties, a beautiful appearance, and a sufficient thickness suitable for use can be easily and continuously and stably produced. The styrene resin extruded foam can be suitably used as a heat insulating material for a house or a structure.

Claims (9)

A styrene-based resin comprising a step of adding a masterbatch having a styrene-based resin content of 50% by weight or more and 99% by weight or less and a polyethylene glycol content of 1% by weight or more and 50% by weight or less. A method for producing a resin extruded foam. It is characterized by including a step of adding the masterbatch to the styrene resin so that the content of polyethylene glycol is 0.05 parts by weight or more and 5.0 parts by weight or less with respect to 100 parts by weight of the styrene resin. The method for producing an extruded styrene resin foam according to claim 1. The styrene-based product according to claim 1 or 2, wherein the amount of hydrofluoroolefin added as a foaming agent to 100 parts by weight of the styrene-based resin is 3.0 parts by weight or more and 14.0 parts by weight or less. A method for producing a resin extruded foam. The styrene resin extruded foam according to any one of claims 1 to 3, wherein graphite is contained in an amount of 1.0 part by weight or more and 5.0 parts by weight or less with respect to 100 parts by weight of the styrene resin. Manufacturing method. The styrene-based resin according to any one of claims 1 to 4, which contains 0.5 parts by weight or more and 5.0 parts by weight or less of a bromine-based flame retardant with respect to 100 parts by weight of the styrene-based resin. A method for producing an extruded foam. The method for producing a styrene-based resin extruded foam according to any one of claims 1 to 5, wherein the polyethylene glycol has an average molecular weight of 1000 or more and 25,000 or less. The method for producing an extruded styrene resin foam according to any one of claims 3 to 6, wherein the hydrofluoroolefin is tetrafluoropropene. The method for producing a styrene-based resin extruded foam according to any one of claims 1 to 7, wherein the thickness of the styrene-based resin extruded foam is 10 mm or more and 150 mm or less. The item according to any one of claims 1 to 8, wherein the styrene resin extruded foam has an apparent density of 20 kg / m ³ or more and 60 kg / m ³ or less, and a closed cell ratio of 80% or more. The method for producing an extruded styrene resin foam according to the above method.