JP2007153964A - Method for manufacturing styrenic resin extruded foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for stably manufacturing a lightweight styrenic resin extruded foam which excels in heat-insulation performance and has a strength and a flame retardance suited for its application as a construction material, by using environmentally compatible water and carbon dioxide as main foaming agents. <P>SOLUTION: In the method for manufacturing the styrenic resin extruded foam, water and carbon dioxide are mainly used as foaming agents, and a styrenic resin having a melt flow rate (MFR) or 2-15g/10 min is used. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plate-like styrene resin extruded foam used for a heat insulating material for buildings and the like and a method for producing the same. More specifically, the present invention relates to a method for producing a styrene resin extruded foam having excellent environmental compatibility and good heat insulation performance, strength properties, and flame retardancy.

Conventionally, styrene resin extruded foam has been widely used as a heat insulating material for buildings because of its workability and suitability for heat insulation. In order to obtain these styrene resin extruded foams, the styrene resin is heated and melted in an extruder, and during the course, a foaming agent is added and kneaded, the fluid gel is cooled to a temperature suitable for foaming, and pressure is applied to the low pressure region through a die. A general method is to open, foam, and at the same time form a plate to obtain a foam.
Here, chlorofluorocarbons and saturated hydrocarbons are used as foaming agents in order to obtain excellent heat insulation properties, and styrene-based materials are used in order to obtain good mechanical properties, foam dimensional stability and productivity. A technique using a halogenated hydrocarbon typified by methyl chloride and ethyl chloride, which are easily permeable gases, is widely used in the industry.

  However, in recent years, environmental issues such as ozone layer destruction, global warming, and the effects of chemical substances on the atmosphere and water quality have been highlighted. For example, chlorofluorocarbons are regulated substances as ozone depleting substances and global warming substances, and are difficult to use. In addition, notification is required for methyl chloride and ethyl chloride as Class 1 Designated Substances under the PRTR Law, and the amount of emissions is controlled. Therefore, it is desired to use a foaming agent that is kind to the environment.

  Based on these backgrounds, studies have been made to make full use of foaming agents suitable for environments such as water and carbon dioxide.

  In Patent Document 1, water and carbon dioxide are used as a foaming agent, and further, a C1-6 alcohol is contained as a foaming agent, and in order to reduce the thermal conductivity, a technique of containing carbon black, Technical content of a foam having relatively large primary bubbles with an average bubble size ranging from 0.05 mm to 1.2 mm and relatively small secondary bubbles with a bubble size ranging from 5 to 50 percent of the average bubble size of the primary bubbles is disclosed Has been. However, when water and carbon dioxide are used as the main foaming agent to obtain a lightweight foam more stably, further improvement in terms of production technology is necessary.

Patent Document 2 discloses a technical content in which bentonite is added as a water dispersion medium, water is effectively used as a foaming agent, and a foam having a large and small cell structure is obtained more advantageously. However, when it is desired to more easily and stably obtain a lightweight foam having a foam density of 20 to 50 kg / m ³ without using a blowing agent of chlorofluorocarbons and halogenated hydrocarbons, further improvement is possible. Was necessary.

  Patent Document 3 discloses a technical content that uses water as a foaming agent and contains zeolite having an average particle diameter of 15 μm or less. However, in order to obtain a lightweight foam more stably, further improvement is required in terms of production technology.

As described above, water and carbon dioxide are used as foaming agents that are compatible with the environment, and the manufacturing method for lightweight styrene resin extruded foam with excellent heat insulation performance, strength properties, and flame resistance is further improved. Is awaited.
JP 7-507592A Japanese Patent Laid-Open No. 2001-200087 JP 2004-182784 A

  The present invention has been made in view of the above prior art, and does not use a foaming agent of chlorofluorocarbons and halogenated hydrocarbons, which have an environmental impact such as ozone layer destruction and global warming, and has excellent heat insulation performance, An object of the present invention is to provide a lightweight styrene resin extruded foam having both strength properties and flame retardancy.

  Water is a clean substance, but when used as a foaming agent for styrene resin extruded foam, there is almost no compatibility with styrene resin, so there is a limit to the amount of addition, and if the amount is too large However, there is a problem that the resin cannot be uniformly dispersed in the resin and cannot be stably extruded and foamed or voids are generated in the foam. Therefore, an effective water-absorbing substance such as found in the examples of bentonite and zeolite has been added, and water has been uniformly dispersed in the resin in the extruder, and it has been found that water can be effectively used as a blowing agent. As a result, to some extent, it has succeeded in developing a foam having excellent heat insulation performance while realizing the use as a foaming agent of water and using an environmentally friendly foaming agent.

  However, in order to produce a foam more economically and to obtain a good foam by increasing the foam, it is necessary to step up the technology.

  Carbon dioxide, on the other hand, is a material that is superior in terms of safety and environmental compatibility compared to blowing agents of chlorofluorocarbons, saturated hydrocarbons, and halogenated hydrocarbons. When used as a foaming agent, a gas is ejected from the die and a good foam cannot be obtained, or voids that lead to poor appearance due to poor gas dispersion are very likely to occur. Further, since the gas escape from the foam is extremely fast, particularly when the foam is highly foamed, the obtained foam is severely contracted immediately after extrusion, and there is a problem that the dimensional stability of the foam is lacking. Furthermore, since it has poor compatibility with polystyrene resins and has a very low boiling point, it has a large nucleation function and has a feature that makes the foam cell diameter extremely small. In this case, there is a problem that the bubble film is easily broken and a good plate-like foam cannot be formed, and a plate-like foam having a particularly large thickness is very difficult to obtain. Although it is possible to add a small amount of carbon dioxide as a nucleating agent or a foaming aid, a more improved production technique is required to stably produce a foam as the main foaming agent.

  Using these water and carbon dioxide as a main foaming agent is very effective and expected in terms of environmental compatibility. However, as described above, it can be said that how to overcome many problems mainly of compatibility with polystyrene resin is a problem for stable production.

  In order to solve the above problems, the present inventors use a polystyrene resin having a specific resin flow characteristic when water and / or carbon dioxide is used as a main foaming agent, and further use a polystyrene resin having a different resin flow characteristic. By combining resins, it is more effective for production stability. Furthermore, it has been found that these techniques make it easy to obtain a foam having a special cell structure in which large and small cells are mixed, and are extremely effective in improving the quality of the foam insulation.

That is, the present invention
(1) A method for producing a styrene resin extruded foam in which a styrene resin is heated and melted, a foaming agent is added to the styrene resin, and extruded through a die, and water and carbon dioxide are used as the foaming agent. And the manufacturing method of the styrene-type resin extrusion foam characterized by using a styrene-type resin whose melt flow rate (MFR) is 2-15 g / 10min as a styrene-type resin to be used.
(2) The styrenic resin as described in (1) above, wherein a styrenic resin having an MFR of 2 to 5 g / 10 min and a styrenic resin having an MFR of 7 to 15 g / 10 min are mixed and used as the resin to be used. Method for producing extruded foam.
(3) The styrene-based resin extruded foam according to (1) or (2) above, wherein the amount of water and carbon dioxide used as the foaming agent is 40 to 100% by weight based on the total amount of the foaming agent. Body manufacturing method.
(4) The foaming agent comprising at least one of ether and a saturated hydrocarbon having 3 to 5 carbon atoms is used as the foaming agent other than water and carbon dioxide (1) to (3) The manufacturing method of the styrene resin extrusion foam of any one of these.
(5) The bubbles constituting the foam are composed of bubbles having a bubble diameter of 0.25 mm or less and bubbles having a bubble diameter of 0.3 to 1 mm, and bubbles having a bubble diameter of 0.25 mm or less are 10 to 90% per foam cross-sectional area. The method for producing a styrene resin extruded foam according to any one of (1) to (4), wherein a foam having an occupied area ratio of 1 is obtained.
(6) The method for producing an extruded foam of styrene resin according to any one of (1) to (5), wherein the styrene resin contains bentonite and / or zeolite.
It is about.

  According to the present invention, a lightweight styrene resin extruded foam having excellent heat insulation, strength suitable for building material use, and flame retardancy can be obtained with a clean foaming agent suitable for the environment.

The present inventors have studied a technique for effectively using water and carbon dioxide as a foaming agent. As a result of investigating the resin flow characteristics of the styrenic resin used in the process, it is surprising that polystyrene resins with specific resin flow characteristics are used, and polystyrene resins with different resin flow characteristics are used. It was found that extrusion foaming was stabilized by combining resins, and it was effective for production stability. In particular, it has been found that these technologies are easy to obtain a foam having a special cell structure in which large and small cells are mixed, and are very effective in improving the quality of the foam insulation.
The present inventors have studied from the viewpoint of the resin flow characteristics of styrene resin. As an evaluation index, a measurement method of melt flow rate (MFR), 200 ° C., and 5 kg load was adopted. Using various styrene resins with different MFRs, and conducting an actual test using an extruder, the use of styrene resins having an MFR of 2 to 15 g / 10 min indicates that water and carbon dioxide are used in the extruder. Good results were obtained by uniformly dispersing carbon in the resin, and an effect on production stability was obtained. In addition, as a styrenic resin to be used, the result that the use of a styrene resin having an MFR of 2 to 5 g / 10 min and a styrene resin having an MFR of 7 to 15 g / 10 min is most excellent in production stability was obtained. . The styrene resin used may be a commercially available resin or a resin recycled by a regenerative extruder or the like.
When the MFR is out of the above range, the function of dispersing and absorbing water and carbon dioxide is reduced, pressure fluctuations are observed in the extrusion system, and the cross-sectional profile of the resulting foam is not constant and fluctuates. However, there is a tendency that a good foam cannot be stably obtained, for example, gas is ejected from the die or voids are generated in the foam.

  The present invention is characterized by using water and carbon dioxide as a blowing agent. In particular, the total number of moles of water and carbon dioxide is 40 to 100% with respect to the total number of moles of the foaming agent, and these clean foaming agents are the main components.

  From the viewpoint of obtaining a foam having a good quality such as stable foam production and appearance, the amount of water added is preferably 0.2 to 5 parts by weight with respect to 100 parts by weight of the styrene resin. Preferably it is 0.5-4 weight part. If the amount of water added is less than the above range, high foaming tends to be difficult. When the amount of water added exceeds the above range, the dispersion and absorption in the styrene resin exceed the allowable range, and gas ejection from the die and the like tend to occur and a good foam cannot be obtained.

  The amount of carbon dioxide added is preferably 0.2 to 7 parts by weight with respect to 100 parts by weight of the styrene resin. Preferably it is 0.5-6 weight part. If the amount of carbon dioxide added is less than the above range, high foaming tends to be difficult. When the amount of carbon dioxide added exceeds the above range, the dispersion and absorption into the styrene resin exceed the allowable range, gas ejection from the die, and the like tend to be difficult to obtain.

  As the foaming agent other than water and carbon dioxide, it is possible to use a foaming agent composed of at least one of ether and a saturated hydrocarbon having 3 to 5 carbon atoms. These non-halogen foaming agents can be more stably reduced in weight and are effective in further improving the foam quality of heat insulation and dimensional stability.

  Examples of the ether include dimethyl ether, diethyl ether, methyl ethyl ether and the like, and dimethyl ether is preferable from the viewpoint of foamability, foam moldability, and stability.

  Examples of the saturated hydrocarbon having 3 to 5 carbon atoms include propane, n-butane, i-butane, n-pentane, i-pentane, neopentane and the like.

  In the case of saturated hydrocarbons having 3 to 5 carbon atoms, n-butane, i-butane, and a mixture of n-butane and i-butane are preferable from the viewpoint of foamability and thermal insulation performance of the foam, and particularly preferably n-butane and i-butane. -A mixture of butanes.

The amount of water, carbon dioxide, and other foaming agents to be used may be changed as appropriate according to the setting value of the foaming ratio, but a lightweight foam having a foam density of 20 to 50 kg / m ³ will be obtained. In this case, the total amount of the foaming agent is preferably 4 to 10 parts by weight, more preferably 6 to 9 parts by weight with respect to 100 parts by weight of the styrene resin. When the total amount of the foaming agent is less than 4 parts by weight, the foaming ratio is low, and the characteristics such as light weight and heat insulation as the resin foam may be difficult to be exhibited. Therefore, it tends to cause defects such as voids in the foam.

  In addition to the foaming agent used in the present invention, a small amount of the following foaming agent can also be used. For example, ketones such as dimethyl ketone, methyl ethyl ketone, 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 Alcohols such as methanol, ethanol, propyl alcohol, i-propyl alcohol, butyl alcohol, i-butyl alcohol, t-butyl alcohol, formic acid methyl ester, formic acid ethyl ester, formic acid propyl ester, formic acid butyl ester, formic acid amyl ester Carboxylic acid esters such as propionic acid methyl ester and propionic acid ethyl ester, inorganic foaming agents such as nitrogen, chemical foaming agents such as azo compounds, and the like can be used.

  The pressure when adding or injecting the foaming agent is not particularly limited as long as it is higher than the internal pressure of an extruder or the like.

  In the present invention, in a specific range where the amount of water added is 0.5 to 3.0 parts, mainly small bubbles having a bubble diameter of 0.25 mm or less and large bubbles having a bubble diameter of 0.3 to 1 mm are passed through the cell membrane. Thus, a foam having a characteristic cell structure dispersed in a sea-island shape is obtained.

  A foam having such a large and small cell structure is excellent in heat insulation performance and mechanical strength. The heat insulation performance of the foam having the large and small cell structure is excellent because the heat flow moving through the uniform cell structure in the conventional foam having the uniform cell structure is less than the cell diameter 0 in the present foam. It is presumed that this is because it is divided by small bubbles having a fine bubble diameter of 0.25 mm or less existing around large bubbles of 3 to 1 mm. In addition, regarding the bending strength and bending deflection, the stress applied to the cell membrane is dispersed by, for example, fine bubbles having a bubble diameter of 0.25 mm or less present in the shape of sea islands, so that it is estimated that suitable bending characteristics are exhibited. .

  In the present invention, when a foam having a bubble structure composed of large and small bubbles is aimed, small bubbles having a bubble diameter of 0.25 mm or less have an occupied area ratio of 10 to 90% per foam cross-sectional area. The occupied area ratio of the small bubbles is preferably 20 to 90%, more preferably 30 to 90%, and most preferably 40 to 90% per cross-sectional area of the foam. As described above, it is preferable that the small bubble occupation area ratio is large because the heat insulation performance is improved.

Moreover, bentonite and zeolite can be used as the adsorbent and dispersant for water and carbon dioxide used in the present invention.
Examples of bentonite include natural bentonite, purified bentonite, and organic bentonite, and examples of zeolite include natural zeolite and synthetic zeolite.

  The styrene resin used in the present invention is not particularly limited, and is obtained from a styrene homopolymer obtained only from a styrene monomer, a monomer copolymerizable with styrene monomer and styrene, or a derivative thereof. Examples thereof include random, block or graft copolymers, post-brominated polystyrene, modified polystyrene such as rubber-reinforced polystyrene, and the like. These can be used alone or in admixture of two or more.

Examples of monomers copolymerizable with styrene include methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, bromostyrene, dibromostyrene, tribromostyrene, chlorostyrene, dichlorostyrene, and trichlorostyrene. Polyfunctional vinyl compounds such as divinylbenzene, (meth) acrylic compounds such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, acrylonitrile, diene compounds such as budadiene or the like Derivatives, unsaturated carboxylic acid anhydrides such as maleic anhydride, itaconic anhydride and the like. These can be used alone or in admixture of two or more.
The styrene resin having an MFR in the above range is approximately 20 × 10 ^{4 to} 35 × 10 ⁴ in terms of the weight average molecular weight Mw.

  In the styrene resin, a styrene homopolymer is preferable from the viewpoint of processability.

  In the present invention, it is preferable to use a flame retardant in the styrene-based resin foam in order to meet the demands in the application. As the flame retardant, it is more preferable to use at least one selected from halogen-based flame retardants. Further, a phosphate ester compound and a nitrogen-containing compound may coexist. Examples of the halogen-based flame retardant used in the present invention include, as brominated flame retardants, hexabromocyclododecane, tetrabromocyclooctane, dibromoneopentyl glycol, tribromoneopentyl alcohol, tris (tribromoneopentyl) phosphate. , Bromides of aliphatic or alicyclic hydrocarbons such as tris (2,3-dibromopropyl) isocyanurate, tetrabromoethane, hexabromobenzene, ethylenebispentabromodiphenyl, decabromodiphenylethane, decabromodiphenyl ether, octa Brominated aromatic compounds such as bromodiphenyl ether and 2,3-dibromopropylpentabromophenyl ether, tetrabromobisphenol A, tetrabromobisphenol A bis (2,3-dibromo Propyl ether), tetrabromobisphenol A (2-bromoethyl ether), tetrabromobisphenol A diglycidyl ether, tetrabromobisphenol A bis (allyl ether), adducts of tetrabromobisphenol A diglycidyl ether and tribromophenol, etc. Brominated bisphenols and their derivatives, tetrabromobisphenol A polycarbonate oligomers, brominated bisphenol derivatives oligomers such as tetrabromobisphenol A diglycidyl ether and brominated bisphenol adduct epoxy oligomers, ethylene bistetrabromophthalimide, bis ( 2,4,6-tribromophenoxy) ethane brominated aromatic compounds, brominated acrylic resins, ethylenebisdibromonor Such Luna Nji dicarboximide and the like. Examples of the chlorine-based flame retardant that is a halogen-based flame retardant include chlorinated aliphatic compounds such as chlorinated paraffin, chlorinated naphthalene, and perchloropentadecane, chlorinated aromatic compounds, and chlorinated alicyclic compounds. Among these, brominated flame retardants are preferable from the viewpoint of flame retardancy, and hexabromocyclododecane, tetrabromocyclooctane, tris (2,3-dibromopropyl) isocyanurate, dibromo are particularly preferable from the viewpoint of compatibility with styrene resins. Neopentyl glycol and tetrabromobisphenol A bis (2,3-dibromopropyl ether) are preferred, and the amount to be added is 0.1 to 6.0 parts by weight. If the content of the halogen-based flame retardant is less than the above, flame retardancy tends to be difficult to obtain. On the other hand, if the content exceeds the above range, the glass transition temperature of the foam tends to decrease and heat resistance tends to decrease.

  Specific examples of phosphoric acid ester compounds include trialkyl phosphates such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri (2-ethylhexyl) phosphate (preferably those having 1 to 12 carbon atoms as the alkyl group), tri Trialkoxyalkyl phosphates such as butoxyethyl phosphate (alkoxyalkyl groups preferably having 2 to 12 carbon atoms), dialkyl phosphates (alkyl groups preferably having 1 to 12 carbon atoms), monoisodecyl phosphate, etc. Fatty substances such as monoalkyl phosphates (alkyl groups having 1 to 12 carbon atoms are preferred), 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate Phosphates, triphenyl phosphate, tricresyl phosphate, trixyl phosphate, tris (isopropylphenyl) phosphate, tris (phenylphenyl) phosphate, trinaphthyl phosphate, cresyl diphenyl phosphate, xylyl diphenyl phosphate, di (isopropyl Triaryl phosphates such as phenyl) phenyl phosphate (the rule group may be substituted with an alkyl group, a phenyl group, etc.), diphenyl (2-ethylhexyl) phosphate, diphenyl (2-acryloyloxyethyl) phosphate, diphenyl (2- Methacryloyloxyethyl) phosphates such as diarylalkyl phosphates (aryl groups, alkyl groups may be substituted) Such group based phosphate esters.

  The content of the phosphoric ester compound is preferably 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the styrene resin in terms of obtaining a flame retardant synergistic effect with the halogen flame retardant and / or the nitrogen-containing compound. .

  Specific examples of the nitrogen-containing compound include monoalkyl cyanurates such as cyanuric acid and methyl cyanurate, dialkyl cyanurates such as diethyl cyanurate, trialkyl cyanurates such as trimethyl cyanurate and triethyl cyanurate, phenyl cyanurate, and diphenyl. Dialkyl phenyl cyanurates such as cyanurate, triphenyl cyanurate, dimethylphenyl cyanurate, monoalkyl isocyanurates such as isocyanuric acid and methyl isocyanurate, dialkyl isocyanurates such as diethyl isocyanurate, trimethyl isocyanurate, triethyl isocyanurate, etc. Trialkyl isocyanurate, phenyl isocyanurate, diphenyl isocyanurate, triphenyl isocyanurate, Dialkylphenyl isocyanurates such as methylphenyl isocyanurate, mono (aminoalkyl) isocyanurates such as mono (2-aminoethyl) isocyanurate, di (aminoalkyl) isocyanurates such as di (2-aminoethyl) isocyanurate, tri Tri (aminoalkyl) isocyanurate such as (2-aminoethyl) isocyanurate, tri (hydroxymethyl) isocyanurate, tri (2-hydroxyethyl) isocyanurate, tri (2-hydroxypropyl) isocyanurate Bis (carboxyl) such as di (hydroxyalkyl) isocyanurate such as alkyl) isocyanurate, di (hydroxymethyl) isocyanurate, and bis (2-carboxyethyl) isocyanurate Kill) isocyanurate, 1,3,5-tris (2-carboxyethyl) isocyanurate and the like 1,3,5-tris (carboxyalkyl) isocyanurate, tris (2,3-epoxypropyl) isocyanurate and the like It is done.

  The content of the nitrogen-containing compound is preferably 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the styrene-based resin in terms of obtaining a flame retardant synergistic effect with the halogen-based flame retardant and / or the phosphate ester compound. .

  Examples of the processing aid used in the present invention include a nucleating agent for adjusting the foam cell diameter, a lubricant for imparting extrusion stability, and the like, such as silica, talc, calcium silicate, wollastonite, kaolin, clay, Inorganic compounds such as mica, zinc oxide, titanium oxide and calcium carbonate, and compounds such as sodium stearate, magnesium stearate, barium stearate, liquid paraffin, olefin wax and stearyl amide compound are used.

  As the stabilizer used in the present invention, light-resistant stabilizers such as phenolic antioxidants, phosphorus stabilizers, benzotriazoles, hindered amines and the like are used.

  In the method for producing a styrene resin foam of the present invention, an additive is mixed with a styrene resin, and then supplied to an extruder and melted by heating. Further, in the extruder, water and carbon dioxide that are press-fitted are contained. Mix and knead together with a foaming agent under high temperature and high pressure to obtain a styrene resin melt composition, then cool to a resin temperature suitable for extrusion foaming with a cooler or the like, and extrude and foam the fluid gel into a low pressure region through a slit die. It is manufactured by forming a foam and foam-molding it into a plate shape.

  There are no particular restrictions on the heating temperature, melt kneading time, and melt kneading means when heating and kneading the styrene resin and additives such as a foaming agent. Although the heating temperature should just be more than the temperature which the styrene resin to be used melt | dissolves, the temperature which suppresses the molecular degradation of resin by the influence of a flame retardant etc. as much as possible, for example, about 150-220 degreeC is preferable. The melt-kneading time varies depending on the amount of extrusion per unit time, the melt-kneading means, etc., and thus cannot be determined unconditionally. However, the time required for uniformly dispersing and mixing the styrenic resin and the foaming agent is appropriately selected. Examples of the melt-kneading means include a screw-type extruder, but there is no particular limitation as long as it is used for ordinary extrusion foaming.

  With regard to the foam molding method, for example, a molding die in which a foam obtained by releasing pressure from a slit die having a linear slit shape used for extrusion molding is placed in close contact with or in contact with the slit die. And the method of shape | molding a plate-shaped foam with a big cross-sectional area using the shaping | molding roll etc. which were installed adjacent to the downstream of this shaping | molding die is used. Furthermore, a method of obtaining a desired foam cross-sectional shape, foam surface property, and foam quality by adjusting the flow surface shape of the molding die and the die temperature is used.

  The average cell diameter in the styrenic resin foam obtained in the present invention is preferably 0.1 to 1.0 mm, more preferably 0.15 to 0.3 mm, from the viewpoint of possessing excellent heat insulation and appropriate strength. 6 mm.

The thickness of the foam of the present invention is not particularly limited and is appropriately selected depending on the application. For example, in the case of a heat insulating material used for a building material or the like, in order to give a preferable heat insulating property, bending strength and compressive strength, the thickness is not as thin as a sheet but as a normal plate. Is preferable, usually 20 to 120 mm, preferably 20 to 100 mm.
Further, the density of the foam of the present invention is preferably lightweight and excellent heat insulating properties and bending strength, in order to allowed to impart compressive strength is 20 to 50 kg / ^{m 3,} in 25~40kg / ^{m 3} More preferably.

  Next, although the styrene resin extrusion foam of this invention and its manufacturing method are demonstrated in detail based on an Example, this invention is not limited only to this Example. Unless otherwise specified, “parts” represents parts by weight, and “%” represents% by weight.

  As the characteristics of the foams obtained in Examples 1 to 7 and Comparative Examples 1 to 3 shown below, the foam molding state, the foam cross-sectional profile, the small cell occupation area ratio, the foam density, the foam thermal conductivity, The foam compressive strength and foam combustibility were determined according to the following methods.

1) Foam molding state It evaluated by the following content.
○: The foam does not have cracks, cracks, dents or voids, and a good foam is stably obtained. The resulting foam has a constant cross-sectional profile.
(Triangle | delta): The pressure fluctuation in an extrusion system is seen, and the cross-sectional profile of the foam obtained is fluctuate | varied not constant.
X: Gas is ejected from the die. The pressure fluctuation in the extrusion system is severe, and a foam cannot be obtained stably. The foam has cracks, cracks, dents, voids, etc., and only a poor foam can be obtained.

2) Foam cross-sectional profile The thickness direction dimension and the width direction dimension of the obtained foam cross section were measured. The thickness direction dimension was determined by an average value of three points at both ends in the width direction and at the center in the width direction.

3) Small bubble occupation area ratio As an indicator of the characteristic foam cell structure in which large and small bubbles are mixed, the small bubble area ratio (ratio of the area occupied by bubbles having a bubble diameter of 0.25 mm or less per cross-sectional area of the foam) is as follows: I asked for it. Here, a bubble having a bubble diameter of 0.25 mm or less is a bubble having a circle-equivalent diameter of 0.25 mm or less.
a) Longitudinal cross section of foam by a scanning electron microscope (manufactured by Hitachi, Ltd., product number: S-450), and the longitudinal direction of the foam (in the direction perpendicular to the extrusion direction and the thickness direction) A photograph taken of a cross-section cut in the same manner.
b) An OHP sheet is placed on the photograph taken, and a portion corresponding to a bubble having a diameter in the thickness direction larger than 7.5 mm (corresponding to a bubble having an actual dimension larger than 0.25 mm) is black ink. Fill in and copy (primary processing).
c) The primary processed image is taken into an image processing apparatus (Pierce Co., Ltd., product number: PIAS-II), and a dark color portion and a light color portion, that is, a portion painted with black ink are identified.
d) Of the dark portion, a portion corresponding to the area of a circle having a diameter of 7.5 mm or less, that is, a portion having a long diameter in the thickness direction but only an area of a circle having a diameter of 7.5 mm or less. Is lightened to correct the dark portion.
e) Using “FRACTAREA (area ratio)” in the image analysis calculation function, the area ratio of the bubble diameter of 7.5 mm or less (light color portion divided by shading) in the entire image is obtained by the following equation.
Occupied area ratio of small bubbles (%) = (1−area of dark portion / area of entire image) × 100
4) Foam density (kg / m ³ )
The foam density was determined based on the following formula, and the unit was shown in terms of kg / m ³ .
Foam density (g / cm ³ ) = foam weight (g) / foam volume (cm ³ )
In this measurement, measurement was performed by sampling with a sample size of product thickness × width 100 mm × length 300 mm at the position in the center of the width direction of the foam (thickness: 20-50 mm, width: 150-200 mm). It calculated | required by the average value of 3 points | pieces.

5) Thermal conductivity of foam (W / mK)
Measured according to JIS A 9511 extrusion method polystyrene foam heat insulating plate. The measurement was performed on a foam that had passed 30 days after production.

6) Foam compressive strength (N / cm ² )
Measured according to JIS A 9511 extrusion method polystyrene foam heat insulating plate. The measurement was performed on a foam that had passed 7 days after production.

7) Foam combustibility Measured according to JIS A 9511. The measurement was performed on a foam that had passed 7 days after production. If the flame is extinguished within 3 seconds and there is no residue and it does not burn beyond the burn-up limit indicator line, it will be ○ (pass), and if this standard is not reached, × (fail) It was.

Example 1
PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 was used as the polystyrene resin, 0.5 parts by weight of bentonite and 0. 5 parts by weight, together with 3 parts by weight of hexabromocyclododecane (hereinafter abbreviated as HBCD) as a halogen flame retardant, 0.1 parts by weight of talc as a nucleating agent, and 0.25 parts by weight of barium stearate as a lubricant Were dry blended and these resin mixtures were fed to a tandem extruder.

  The resin mixture supplied to the first extruder is melted and kneaded by heating to about 200 ° C., and 1 part by weight of water and 4 parts by weight of carbon dioxide are added to 100 parts by weight of polystyrene resin as a foaming agent. Press-fitted into the resin near the tip. Then, it cools, knead | mixing with the 2nd extruder connected with the 1st extruder, and also a cooler, and the foaming resin temperature is about 110-140 degreeC in air | atmosphere from the slit die provided in the front-end | tip of a cooler. After extrusion foaming, an extruded foam plate having a cross-sectional shape having a thickness of 30 mm and a width of 150 mm was obtained by a molding die placed in close contact with the slit die and a molding roll placed downstream thereof.

The obtained foam had a characteristic cell structure in which large and small bubbles were mixed, and was a good foam having a small bubble occupation area ratio of 25% and a foam density of 39.2 kg / m ³ . The obtained foam had a thermal conductivity of 0.037 W / mK, a compressive strength of 47.5 N / cm ² , and flammability met JIS A 9511 standards.

(Example 2)
As the polystyrene resin, the polystyrene resin once processed into a foamed product or the like is finely pulverized, and again using a polystyrene resin, MFR = 5, which is heat-melted and pelletized using an extruder, polystyrene resin 100 As an adsorbent with respect to parts by weight, 0.5 parts by weight of bentonite, 0.5 parts by weight of zeolite, 3 parts by weight of HBCD as a halogen-based flame retardant, 0.1 parts by weight of talc as a nucleating agent, As a lubricant, 0.25 parts by weight of barium stearate was dry blended, and these resin mixtures were supplied to a tandem extruder.

  The resin mixture supplied to the first extruder is melted and kneaded by heating to about 200 ° C., and 1 part by weight of water and 4 parts by weight of carbon dioxide are added to 100 parts by weight of polystyrene resin as a foaming agent. Press-fitted into the resin near the tip. Then, it cools, knead | mixing with the 2nd extruder connected with the 1st extruder, and also a cooler, and the foaming resin temperature is about 110-140 degreeC in air | atmosphere from the slit die provided in the front-end | tip of a cooler. After extrusion foaming, an extruded foam plate having a cross-sectional shape having a thickness of 30 mm and a width of 150 mm was obtained by a molding die placed in close contact with the slit die and a molding roll placed downstream thereof.

The obtained foam had a characteristic cell structure in which large and small bubbles were mixed, and was a good foam having a small bubble occupation area ratio of 20% and a foam density of 38.3 kg / m ³ . The obtained foam had a thermal conductivity of 0.038 W / mK, a compressive strength of 46.6 N / cm ² , and flammability met JIS A 9511 standards.

(Example 3)
As the polystyrene resin, a polystyrene resin once processed into a foamed product or the like is finely pulverized, and again is melted and pelletized by using an extruder, MFR = 15. As an adsorbent with respect to parts by weight, 0.5 parts by weight of bentonite, 0.5 parts by weight of zeolite, 3 parts by weight of HBCD as a halogen-based flame retardant, 0.1 parts by weight of talc as a nucleating agent, As a lubricant, 0.25 parts by weight of barium stearate was dry blended, and these resin mixtures were supplied to a tandem extruder.

  The resin mixture supplied to the first extruder is melted and kneaded by heating to about 200 ° C., and 1.5 parts by weight of water and 3 parts by weight of carbon dioxide are first extruded as 100 parts by weight of polystyrene resin as a foaming agent. It was press-fitted into the resin near the tip of the machine. Then, it cools, knead | mixing with the 2nd extruder connected with the 1st extruder, and also a cooler, and the foaming resin temperature is about 110-140 degreeC in air | atmosphere from the slit die provided in the front-end | tip of a cooler. After extrusion foaming, an extruded foam plate having a cross-sectional shape having a thickness of 40 mm and a width of 160 mm was obtained using a molding die placed in close contact with the slit die and a molding roll placed downstream thereof.

The obtained foam had a characteristic cell structure in which large and small bubbles were mixed, and was a good foam having a small bubble occupation area ratio of 15% and a foam density of 37.4 kg / m ³ . The obtained foam had a thermal conductivity of 0.038 W / mK, a compressive strength of 45.5 N / cm ² , and flammability met the standards of JIS A 9511.

Example 4
As polystyrene resin, PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 and 50 parts by weight of polystyrene resin once processed into foamed product, etc. are finely crushed, and again using an extruder 50 parts by weight of polystyrene resin, MFR = 5, which has been melted and pelletized by heating, and 0.5 parts by weight of bentonite and 0.5 parts by weight of zeolite as an adsorbent with respect to 100 parts by weight of total polystyrene resin In addition, 3 parts by weight of HBCD as a halogen-based flame retardant, 0.1 part by weight of talc as a nucleating agent, and 0.25 part by weight of barium stearate as a lubricant are dry blended, and these resin mixtures are tandem type extruders Supplied.

  The resin mixture supplied to the first extruder is melted and kneaded by heating to about 200 ° C., and 1.5 parts by weight of water and 3 parts by weight of carbon dioxide are first extruded as 100 parts by weight of polystyrene resin as a foaming agent. It was press-fitted into the resin near the tip of the machine. Then, it cools, knead | mixing with the 2nd extruder connected with the 1st extruder, and also a cooler, and the foaming resin temperature is about 110-140 degreeC in air | atmosphere from the slit die provided in the front-end | tip of a cooler. After extrusion foaming, an extruded foam plate having a cross-sectional shape having a thickness of 40 mm and a width of 160 mm was obtained using a molding die placed in close contact with the slit die and a molding roll placed downstream thereof.

The obtained foam had a characteristic cell structure in which large and small bubbles were mixed, and was a good foam having a small bubble occupation area ratio of 50% and a foam density of 38.3 kg / m ³ . The obtained foam had a thermal conductivity of 0.035 W / mK, a compressive strength of 43.6 N / cm ² , and flammability met JIS A 9511 standards.

(Example 5)
As a polystyrene resin, once a polystyrene resin processed into a foamed product or the like is finely pulverized, and again, a polystyrene resin thermally melted and pelletized using an extruder, MFR = 5, once with 50 parts by weight, Using polystyrene resin, polystyrene resin, and 50 parts by weight of polystyrene resin, MFR = 15, which has been finely pulverized and then melted and pelletized again using an extruder, the total polystyrene resin 100 parts by weight as an adsorbent, 0.5 parts by weight of bentonite and 0.5 parts by weight of zeolite, 3 parts by weight of HBCD as a halogen flame retardant, and 0.1 parts by weight of talc as a nucleating agent Then, 0.25 parts by weight of barium stearate as a lubricant is dry blended, and these resin mixtures are fed to a tandem extruder. .

  The resin mixture supplied to the first extruder is melted and kneaded by heating to about 200 ° C., and 1.5 parts by weight of water, 3 parts by weight of carbon dioxide and 2 parts by weight of dimethyl ether with respect to 100 parts by weight of polystyrene resin as a foaming agent. The part was pressed into the resin near the tip of the first extruder. Then, it cools, knead | mixing with the 2nd extruder connected with the 1st extruder, and also a cooler, and the foaming resin temperature is about 110-140 degreeC in air | atmosphere from the slit die provided in the front-end | tip of a cooler. After extrusion foaming, an extruded foam plate having a cross-sectional shape having a thickness of 45 mm and a width of 170 mm was obtained by a molding die placed in close contact with the slit die and a molding roll placed downstream thereof.

The obtained foam had a characteristic cell structure in which large and small bubbles were mixed, and was a good foam having a small bubble occupation area ratio of 40% and a foam density of 34.5 kg / m ³ . The obtained foam had a thermal conductivity of 0.035 W / mK, a compressive strength of 40.3 N / cm ² , and flammability met JIS A 9511 standards.

(Example 6)
As polystyrene resin, PS Japan Co., Ltd., trade name: G9401, MFR = 2.2, 30 parts by weight and once pulverized polystyrene resin processed into foamed products, etc., again using an extruder 70 parts by weight of a heat-melted and pelletized polystyrene resin, MFR = 15, and 0.5 parts by weight of bentonite and 0.5 parts by weight of zeolite as an adsorbent with respect to 100 parts by weight of the total polystyrene resin In addition, 3 parts by weight of HBCD as a halogen-based flame retardant, 0.1 part by weight of talc as a nucleating agent, and 0.25 part by weight of barium stearate as a lubricant are dry blended, and these resin mixtures are tandem type extruders Supplied.

  The resin mixture supplied to the first extruder is melted and kneaded by heating to about 200 ° C., and 1.5 parts by weight of water, 3 parts by weight of carbon dioxide and 2 parts by weight of dimethyl ether with respect to 100 parts by weight of polystyrene resin as a foaming agent. The part was pressed into the resin near the tip of the first extruder. Then, it cools, knead | mixing with the 2nd extruder connected with the 1st extruder, and also a cooler, and the foaming resin temperature is about 110-140 degreeC in air | atmosphere from the slit die provided in the front-end | tip of a cooler. After extrusion foaming, an extruded foam plate having a cross-sectional shape having a thickness of 45 mm and a width of 170 mm was obtained by a molding die placed in close contact with the slit die and a molding roll placed downstream thereof.

The obtained foam had a characteristic cell structure in which large and small bubbles were mixed, and was a good foam having a small bubble occupation area ratio of 40% and a foam density of 33.9 kg / m ³ . The obtained foam had a thermal conductivity of 0.035 W / mK, a compressive strength of 37.1 N / cm ² , and a combustibility that met the standards of JIS A 9511.

(Example 7)
As polystyrene resin, PS Japan Co., Ltd., trade name: G9401, MFR = 2.2 and 50 parts by weight of polystyrene resin once processed into foamed product, etc. are finely crushed, and again using an extruder 50 parts by weight of polystyrene resin, MFR = 15, which has been heat-melted and pelleted, and 0.5 parts by weight of bentonite and 0.5 parts by weight of zeolite as adsorbent with respect to 100 parts by weight of total polystyrene resin In addition, 3 parts by weight of HBCD as a halogen-based flame retardant, 0.1 part by weight of talc as a nucleating agent, and 0.25 part by weight of barium stearate as a lubricant are dry blended, and these resin mixtures are tandem type extruders Supplied.

  The resin mixture supplied to the first extruder is melted and kneaded by heating to about 200 ° C., and 1.5 parts by weight of water, 3 parts by weight of carbon dioxide and 2 parts by weight of isobutane with respect to 100 parts by weight of polystyrene resin as a foaming agent. The part was pressed into the resin near the tip of the first extruder. Then, it cools, knead | mixing with the 2nd extruder connected with the 1st extruder, and also a cooler, and the foaming resin temperature is about 110-140 degreeC in air | atmosphere from the slit die provided in the front-end | tip of a cooler. After extrusion foaming, an extruded foam plate having a cross-sectional shape having a thickness of 45 mm and a width of 170 mm was obtained by a molding die placed in close contact with the slit die and a molding roll placed downstream thereof.

The obtained foam had a characteristic cell structure in which large and small bubbles were mixed, and was a good foam having a small bubble occupation area ratio of 50% and a foam density of 34.3 kg / m ³ . The obtained foam had a thermal conductivity of 0.031 W / mK, a compressive strength of 36.6 N / cm ² , and a combustibility that satisfied the standards of JIS A 9511.

(Comparative Example 1)
PS Japan Co., Ltd. product name: HH105, MFR = 1.3 is used as the polystyrene resin, and 0.5 parts by weight of bentonite and 0. In addition, 5 parts by weight, dry blend of 3 parts by weight of HBCD as a halogen-based flame retardant, 0.1 part by weight of talc as a nucleating agent, and 0.25 part by weight of barium stearate as a lubricant, these resin mixtures are tandem type Feeded to the extruder.

  The resin mixture supplied to the first extruder is heated to about 200 ° C. and melt-kneaded. As a foaming agent, 1 part by weight of water and 4 parts by weight of carbon dioxide are added to 100 parts by weight of polystyrene resin. Was pressed into the resin in the vicinity of the tip. Then, it cools, knead | mixing with the 2nd extruder connected with the 1st extruder, and also a cooler, and the foaming resin temperature is about 110-140 degreeC in air | atmosphere from the slit die provided in the front-end | tip of a cooler. After extrusion foaming, an extruded foam plate was obtained with a molding die placed in close contact with the slit die and a molding roll placed downstream thereof. However, pressure fluctuation in the extrusion system was observed, and the cross-sectional profile of the obtained foam was not constant and fluctuated.

The cross-sectional shape of the foam varied in the range of thickness 30 to 35 mm and width 150 to 180 mm. The obtained foam had a characteristic cell structure in which large and small bubbles were mixed, but the small bubble occupation area ratio was 5%. The foam density was 47.3 kg / m ³ , the thermal conductivity of the foam was 0.041 W / mK, the compressive strength was 55.3 N / cm ² , and the flammability met JIS A 9511 standards.

(Comparative Example 2)
As the polystyrene resin, the polystyrene resin once processed into a foamed product or the like is finely pulverized, and again using a polystyrene resin, MFR = 20, which is thermally melted and pelletized using an extruder, polystyrene resin 100 As an adsorbent with respect to parts by weight, 0.5 parts by weight of bentonite, 0.5 parts by weight of zeolite, 3 parts by weight of HBCD as a halogen-based flame retardant, 0.1 parts by weight of talc as a nucleating agent, As a lubricant, 0.25 parts by weight of barium stearate was dry blended, and these resin mixtures were supplied to a tandem extruder.

  The resin mixture supplied to the first extruder is heated to about 200 ° C. and melt-kneaded. As a foaming agent, 1 part by weight of water and 4 parts by weight of carbon dioxide are added to 100 parts by weight of polystyrene resin. Was pressed into the resin in the vicinity of the tip. Then, it cools, knead | mixing with the 2nd extruder connected with the 1st extruder, and also a cooler, and the foaming resin temperature is about 110-140 degreeC in air | atmosphere from the slit die provided in the front-end | tip of a cooler. After extrusion foaming, an extruded foam plate was obtained with a molding die placed in close contact with the slit die and a molding roll placed downstream thereof. However, pressure fluctuation in the extrusion system was observed, and the cross-sectional profile of the obtained foam was not constant and fluctuated.

The cross-sectional shape of the foam varied in the range of 35 to 40 mm in thickness and 160 to 190 mm in width. The obtained foam had a characteristic cell structure in which large and small bubbles were mixed, but the small bubble occupation area ratio was 5%. The foam density was 45.6 kg / m ³ , the thermal conductivity of the foam was 0.039 W / mK, the compressive strength was 51.6 N / cm ² , and the flammability met JIS A 9511 standards.

(Comparative Example 3)
PS Japan Co., Ltd., trade name: HH105, MFR = 1.3 is used as the polystyrene resin, no adsorbent is added to 100 parts by weight of the polystyrene resin, and 3 parts by weight of HBCD is used as a halogen flame retardant. Then, 0.1 parts by weight of talc as a nucleating agent and 0.25 parts by weight of barium stearate as a lubricant were dry blended, and these resin mixtures were supplied to a tandem extruder.

The resin mixture supplied to the first extruder is heated to about 200 ° C. and melt-kneaded. As a foaming agent, 1 part by weight of water and 4 parts by weight of carbon dioxide are added to 100 parts by weight of polystyrene resin. Was pressed into the resin in the vicinity of the tip. Then, it cools, knead | mixing with the 2nd extruder connected with the 1st extruder, and also a cooler, and the foaming resin temperature is about 110-140 degreeC in air | atmosphere from the slit die provided in the front-end | tip of a cooler. After extrusion foaming, an extrusion foamed plate was obtained using a molding die placed in close contact with the slit die and a molding roll placed downstream thereof. However, gas was ejected from the die, and pressure fluctuations in the extrusion system were so severe that the desired foam could not be obtained stably.
Although the foam was poor, the foam physical properties were evaluated as much as possible. The cross-sectional shape of the foam varies with a thickness of 30 to 40 mm and a width of 140 to 190 mm. The obtained foam had a uniform cell structure, not a characteristic cell structure in which large and small bubbles were mixed, and the area occupied by small bubbles was 0%. The foam density is 47.3 kg / m ³ . The foam thermal conductivity was 0.042 W / mK, the compressive strength was 55.2 N / cm ² , and the flammability met JIS A 9511 standards.

  The results obtained in Examples 1-7 and Comparative Examples 1-3 are summarized in Table 1.

Claims (6)

  A method for producing an extruded foam of a styrenic resin in which a styrenic resin is heated and melted, a foaming agent is added to the styrenic resin, and extruded through a die, and water and carbon dioxide are used as the foaming agent, and A method for producing a styrene resin extruded foam, wherein a styrene resin having a melt flow rate (MFR) of 2 to 15 g / 10 min is used as the styrene resin to be used.   2. The styrene resin extruded foam according to claim 1, wherein a styrene resin having an MFR of 2 to 5 g / 10 min and a styrene resin having an MFR of 7 to 15 g / 10 min are mixed and used as the resin to be used. Method.   3. The styrene resin extruded foam according to claim 1, wherein the total number of moles of water and carbon dioxide used is 40 to 100% with respect to the number of moles of the total amount of the foaming agent. Manufacturing method.   The foaming agent which consists of at least 1 or more types of ether and a C3-C5 saturated hydrocarbon is used as foaming agents other than water and a carbon dioxide, The any one of Claims 1-3 characterized by the above-mentioned. Of producing a styrene resin extruded foam.   The bubbles constituting the foam are composed of bubbles having a bubble diameter of 0.25 mm or less and bubbles having a bubble diameter of 0.3 to 1 mm, and the bubbles having a bubble diameter of 0.25 mm or less occupy an area of 10 to 90% per foam cross-sectional area. The method for producing a styrene resin extruded foam according to any one of claims 1 to 4, wherein a foam having a rate is obtained. 6. The method for producing a styrene resin extruded foam according to any one of claims 1 to 5, wherein the styrene resin contains bentonite and / or zeolite.