JP6688194B2 - Resin composition for foamed resin sheet, and foamed resin sheet - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a resin composition for a foamed resin sheet and a foamed resin sheet using the composition.

  Foamed resin sheets are widely used in applications requiring lightweight, heat insulation, sound insulation, and vibration isolation. For example, in building materials, foamed resin sheets are used for floor materials, wall materials, doors, window frames, etc. for the purpose of sound insulation, heat insulation, and vibration isolation.

  As a general method for producing a foamed resin sheet, a method is used in which a chemical foaming agent is added to a thermoplastic resin serving as a matrix, and the foaming agent is decomposed and vaporized during heat molding to obtain a foam. However, the method using a chemical foaming agent has a problem that it is difficult to control the size and distribution of pores.

Furthermore, when a sheet is used as a building material such as a floor material, a wall material, a door or a window frame, it is required to have flame retardancy in addition to the above-mentioned performance.

  As means for solving the above problems, for example, in Patent Document 1, a thermally expandable microcapsule is blended with a thermoplastic resin, and the thermally expandable microcapsule is expanded by kneading and melting heat by extrusion molding or injection molding. There is disclosed a foam molding method which is characterized by molding by molding. Further, Patent Document 2 discloses a molding method characterized in that a soft vinyl chloride resin composition is blended with heat-expandable microcapsules and extrusion-molded at a temperature not lower than the expansion start temperature of the heat-expandable microcapsules. . Further, Patent Document 3 discloses a vinyl chloride resin composition in which a thermally expandable microcapsule and a perchlorate compound are mixed with a vinyl chloride resin.

JP, 10-152575, A JP, 11-060868, A JP 2000-290418 A

When the molding method described in Patent Document 1 is applied to a polyvinyl chloride-based resin, the polyvinyl chloride-based resin has insufficient mechanical properties such as flexibility and tensile elongation at break, and thus is molded into a sheet shape. However, there is a problem of poor workability. In addition, the molding method described in Patent Document 2 has a problem that when molding into a thin sheet shape, the melt tension is low, and it is difficult to obtain a uniform foamed resin sheet, resulting in poor productivity. Further, by adding the perchloric acid compound described in Patent Document 3, it is possible to suppress the coloring of the vinyl chloride resin due to the heat-expandable microcapsules, but like Patent Document 2, the melt tension is low. However, the productivity, particularly continuous productivity, when forming into a thin sheet was insufficient. Further, the conventional foamed resin sheet has room for improvement in heat insulation and lightness.
Furthermore, the above-mentioned conventional technique has a problem that it cannot be used in applications requiring flame retardancy.

  In view of such problems of the prior art, the present invention provides a foamed resin sheet having excellent moldability, heat insulation, lightness, mechanical properties and flame retardancy, and a resin composition for a foamed resin sheet used therein. The purpose is to

  The inventors of the present invention have earnestly studied and found that a polyvinyl chloride-based resin has a predetermined amount of a phosphorus-based flame retardant, a resin composition in which thermal expansion microcapsules are added, and the resin composition is heat-molded. The inventors have found that the obtained foamed resin sheet can solve the above-mentioned problems, and have reached the present invention.

  In the present specification, as a first aspect, 20 to 55 parts by mass of a phosphorus-based flame retardant (B) and 1 to 100 parts by mass of a thermal expansion microcapsule (C) are used with respect to 100 parts by mass of a polyvinyl chloride resin (A). Disclosed is a resin composition for a foamed resin sheet, which contains 20 parts by mass.

  In the first aspect, the phosphorus-based flame retardant (B) is preferably an aromatic phosphate ester-based flame retardant.

  In the first aspect, it is preferable to further contain 1 to 30 parts by mass of the ethylene copolymerized polyvinyl chloride resin (D) with respect to 100 parts by mass of the polyvinyl chloride resin (A).

  As a second aspect, the present specification relates to a foamed resin sheet obtained by heat-molding the resin composition for a foamed resin sheet according to the first aspect, wherein the heat-expansion is caused by heat applied during the heat-molding. Disclosed is a foamed resin sheet having the thermally expanded microcapsules (C).

As a third aspect, the present specification describes a thermal expansion in a matrix containing 20 to 55 parts by mass of a phosphorus flame retardant (B) with respect to 100 parts by mass of a polyvinyl chloride resin (A). Disclosed is a foamed resin sheet having closed cells due to the microcapsules (C) and having an apparent density of 0.10 to 0.90 g / cm ³ .

  In the third aspect, the closed cells resulting from the thermally expanded microcapsules (C) are thermally expanded thermally expanded microcapsules.

  The foamed resin sheets of the second and third aspects preferably have a tensile elongation at break measured according to JIS K7127 of 50% or more, and a thermal conductivity of 0.1 W / m · K. The following is preferable.

  The present specification discloses, as a fourth aspect, a laminated sheet including at least one layer of the foamed resin sheet of the second and third aspects.

  In the laminated sheet according to the fourth aspect, it is preferable that the foamed resin sheet is provided in at least the intermediate layer.

  As a fifth aspect, the present specification comprises a step of heat-molding the resin composition for a foamed resin sheet of the first aspect, wherein the thermal expansion microcapsules (C) are heated by heat applied during the heat-molding. Disclosed is a method for producing a foamed resin sheet, which comprises expanding a resin.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the foaming resin sheet which is excellent in moldability, heat insulation, lightness, mechanical characteristics, and flame retardancy, and the resin composition for foaming resin sheets used for this.

  Hereinafter, a foamed resin sheet as an example of an embodiment of the present invention will be described. However, the scope of the present invention is not limited to the embodiments described below. Unless otherwise specified, the notation “A to B” for the numerical values A and B means “A or more and B or less”. When a unit is attached only to the numerical value B in such notation, the unit shall be applied to the numerical value A as well.

[Resin composition for foamed resin sheet]
The resin composition used for the foamed resin sheet of the present invention (resin composition for foamed resin sheet) contains 20 to 55 parts by mass of the phosphorus flame retardant (B) with respect to 100 parts by mass of the polyvinyl chloride resin (A). , 1 to 20 parts by mass of the thermal expansion microcapsule (C). Further, it is preferable to further contain 1 to 30 parts by mass of the ethylene copolymerized polyvinyl chloride resin (D) with respect to 100 parts by mass of the polyvinyl chloride resin (A). Hereinafter, each component which comprises the resin composition for foamed resin sheets of this invention is demonstrated.

<Polyvinyl chloride resin (A)>
As the polyvinyl chloride resin (A) used in the present invention, a polyvinyl chloride resin having an arbitrary average degree of polymerization can be used. Preferably, the polyvinyl chloride resin (A) has an average degree of polymerization of 600 to 2,000. If the average degree of polymerization is 600 or more, sufficient mechanical strength can be obtained. On the other hand, when the average degree of polymerization is 2,000 or less, heat generation due to an increase in melt viscosity does not occur, and coloring due to decomposition can be eliminated.

  Therefore, from such a viewpoint, the average degree of polymerization of the polyvinyl chloride resin (A) is more preferably 800 or more and 1,500 or less in the above range, and more preferably 900 or more, 1,300 among them. The following is more preferable.

  Examples of the polyvinyl chloride resin (A) include a homopolymer of polyvinyl chloride (referred to as “polyvinyl chloride homopolymer”) and a copolymer of a monomer copolymerizable with polyvinyl chloride. (Hereinafter, referred to as "polyvinyl chloride copolymer"), a graft copolymer obtained by graft copolymerizing vinyl chloride with a polymer other than the polyvinyl chloride copolymer (hereinafter, referred to as a polyvinyl chloride graft copolymer). Polymers) and the like.

  Polyvinyl chloride-based copolymers have poor mechanical properties when the content of constitutional units other than polyvinyl chloride in the copolymer increases, so the proportion of vinyl chloride in the polyvinyl chloride-based copolymer is It is preferably from 60 to 99 mass%.

  The polyvinyl chloride-based homopolymer and the polyvinyl chloride-based copolymer can be polymerized by any method such as an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, and a bulk polymerization method.

  Here, the monomer copolymerizable with polyvinyl chloride may be any monomer having a reactive double bond in the molecule. For example, α-olefins such as propylene and butylene, vinyl acetates such as vinyl acetate and vinyl propionate, vinyl ethers such as butyl vinyl ether and cetyl vinyl ether; unsaturated carboxylic acids such as acrylic acid and methacrylic acid, methyl acrylate, Acrylic acid or methacrylic acid esters such as ethyl methacrylate and phenyl methacrylate, aromatic vinyls such as styrene and α-methylstyrene, vinyl halides such as vinylidene chloride and vinyl fluoride, N-phenylmaleimide, N Examples thereof include N-substituted maleimides such as -cyclohexylmaleimide, and these can be used alone or in combination of two or more.

  As the polymer other than the polyvinyl chloride-based copolymer, any polymer capable of graft-copolymerizing vinyl chloride may be used. For example, ethylene / vinyl acetate copolymer, ethylene / vinyl acetate / carbon monoxide copolymer, ethylene / ethyl acrylate copolymer, ethylene / ethyl acrylate / carbon monoxide copolymer, ethylene / methyl methacrylate copolymer, ethylene -Propylene copolymer, acrylonitrile-butadiene copolymer, polyurethane, chlorinated polyethylene, chlorinated polypropylene and the like can be mentioned, and these can be used alone or in combination of two or more kinds.

<Phosphorus flame retardant (B)>
The phosphorus flame retardant used in the present invention is not particularly limited as long as it has good compatibility with the polyvinyl chloride resin (A), and a known aromatic phosphate ester flame retardant is used. You can Examples of such an aromatic phosphate ester flame retardant include tris (isopropylphenyl) phosphate, cresyldiphenylphosphate, tricresylphosphate, triphenylphosphate, trixylenylphosphate, 2-ethylhexyldiphenylphosphate, 2- Naphthyl diphenyl phosphate, cresyl di 2,6-xylenyl phosphate and the like can be mentioned. These may be used alone or in combination of two or more.

  These organophosphorus flame retardants also act as a plasticizer for the polyvinyl chloride resin (A), have flexibility without hindering the plasticization efficiency, and have the functions of plasticizing and flame retarding. it can.

<Thermal expansion microcapsule (C)>
The thermal expansion microcapsule (C) used in the present invention is a shell composed of an acrylonitrile / methacrylonitrile / vinyl acetate copolymer and volatile substances such as butane, pentane, hexane, cyclohexane, toluene and xylene enclosed in the shell. It is a capsule made of a liquid, and the expansion start temperature is preferably 100 to 180 ° C. By setting the temperature at which the expansion starts to 100 ° C. or higher, expansion of the thermal expansion microcapsules (C) at the initial stage of molding can be suppressed. Further, by setting the expansion start temperature to 180 ° C. or lower, the thermal expansion microcapsules (C) start to expand at the molding temperature when the resin composition for a foamed resin sheet is heat-molded, and a predetermined foamed resin sheet It can be molded. The expansion start temperature is more preferably 110 to 155 ° C, further preferably 120 to 155 ° C.

  Examples of the thermal expansion microcapsules (C) used in the present invention include "Matsumoto Microsphere" series manufactured by Matsumoto Yushi-Seiyaku Co., Ltd., "EXPANCEL" series manufactured by Akzo Nobel, and "ADVANCEL" series manufactured by Sekisui Chemical Co., Ltd. .

<Ethylene copolymerized polyvinyl chloride resin (D)>
The resin composition for a foamed resin sheet of the present invention may further contain 1 to 30 parts by mass of an ethylene copolymerized polyvinyl chloride resin (D) obtained by copolymerizing ethylene, which is an α-olefin, with vinyl chloride. preferable. By containing the ethylene-copolymerized polyvinyl chloride resin (D), the affinity between the polyvinyl chloride resin (A) and the thermal expansion microcapsules (C) is improved, and plate-out occurs during melt processing. By suppressing, a foamed resin sheet having a particularly good appearance can be obtained.

  The polyvinyl chloride-based resin (A), the phosphorus-based flame retardant (B), the thermal expansion microcapsule (C), and the ethylene copolymerized polyvinyl chloride resin (D) which can be preferably contained in the present invention are used. The mixing method is not particularly limited, and the mixing can be performed using a general stirrer.

<Plasticizer (E)>
The resin composition for a foamed resin sheet of the present invention preferably further contains a plasticizer (E). The phosphorus-based flame retardant (B) used in the present invention also acts as a plasticizer, but by adding another plasticizer (E) thereto, the resin composition for a foamed resin sheet can have more optimal flexibility. Can be granted.

  The plasticizer (E) that can be used in the present invention is not particularly limited, and known plasticizers can be used. For example, di-n-butyl phthalate, di-n-octyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, dioctyldecyl phthalate, diisodecyl phthalate, butylbenzyl phthalate, di-2-isophthalate. Phthalates plasticizers such as ethylhexyl, 2-ethylhexyl adipate, di-2-decyl adipate, dibutyl sebacate, fatty acid ester plasticizers such as 2-ethylhexyl sebacate, tributyl phosphate, tri-2 phosphate -Aliphatic phosphate ester plasticizers such as ethylhexyl, trimellitic acid tri-2-ethylhexyl, trimellitic acid ester plasticizers such as trioctyl trimellitate, adipic acid polyester plasticizers, phthalic acid polyester plasticizers, etc. Polyester plasticizer, terephthalate Acid plasticizers, epoxidized soybean oil, epoxidized linseed oil, epoxidized cottonseed oil, epoxidized peanut oil, epoxidized safflower oil, epoxidized grape seed oil, epoxidized vegetable oils such as epoxidized olive oil and the like. These may be used alone or in combination of two or more.

<Flame retardant aid (F)>
Furthermore, the present invention may contain a flame retardant aid (F). As the flame retardant aid (F), known flame retardant aids can be used, and examples thereof include antimony trioxide, antimony pentoxide, antimony tetraoxide, hexaantimony trioxide, crystalline antimonic acid, sodium antimonate, and antimony. Examples thereof include barium acid, lithium antimonate, zinc borate, zinc stannate, basic zinc molybdate, calcium zinc molybdate, molybdenum oxide, zirconium oxide, zinc oxide, iron oxide, red phosphorus and carbon black. Among these, antimony trioxide can be more preferably used.

<Content ratio of each component>
It is important that the compounding amount of the phosphorus-based flame retardant (B) with respect to 100 parts by mass of the polyvinyl chloride resin (A) is 20 to 55 parts by mass. When the compounding amount of the phosphorus-based flame retardant (B) is 20 parts by mass or more, a foamed resin sheet having excellent flame retardancy can be obtained. On the other hand, when the compounding amount of the phosphorus-based flame retardant (B) is 55 parts by mass or less, a foamed resin sheet having practically sufficient flame retardancy can be obtained, and the melt tension at the time of processing does not decrease excessively and is easily manufactured. Membranes are possible. The lower limit of the compounding amount of the phosphorus-based flame retardant (B) is preferably 25 parts by mass or more, and more preferably 30 parts by mass or more. Moreover, the upper limit of the amount of the phosphorus-based flame retardant (B) compounded is preferably 50 parts by mass or less, and more preferably 45 parts by mass or less.

It is important that the compounding amount of the thermal expansion microcapsules (C) with respect to 100 parts by mass of the polyvinyl chloride resin (A) is 1 to 20 parts by mass. By setting the blending amount of the thermal expansion microcapsules (C) to 1 part by mass or more, it is possible to impart sufficient heat insulating properties to the obtained foamed resin sheet, and to reduce the weight of the foamed resin sheet. Become. On the other hand, by setting the blending amount of the thermal expansion microcapsules (C) to 20 parts by mass or less, it is possible to suppress a decrease in mechanical strength, and a more preferable appearance can be obtained.
The lower limit of the compounding amount of the thermal expansion microcapsules (C) is preferably 2 parts by mass or more, and more preferably 2.5 parts by mass or more. Further, the upper limit of the amount of the thermally expanded microcapsules (C) blended is preferably 17 parts by mass or less, and more preferably 15 parts by mass or less.

The blending amount of the ethylene copolymerized polyvinyl chloride resin (D) with respect to the polyvinyl chloride resin (A) is preferably 1 to 30 parts by mass. By adjusting the amount of the ethylene copolymerized polyvinyl chloride resin (D) to be 1 part by mass or more, the affinity between the polyvinyl chloride resin (A) and the thermal expansion microcapsules (C) can be further improved. Therefore, the plate-out of the thermal expansion microcapsules (C) can be suppressed. On the other hand, when the blending amount of the ethylene copolymerized polyvinyl chloride resin (D) is 30 parts by mass or less, it is possible to prevent the melt tension from decreasing and making stable film formation difficult.
The lower limit of the blending amount of the ethylene copolymerized polyvinyl chloride resin (D) is more preferably 1.5 parts by mass or more, and further preferably 2 parts by mass or more. Further, the upper limit of the blending amount of the ethylene copolymerized polyvinyl chloride resin (D) is more preferably 20 parts by mass or less, and further preferably 15 parts by mass or less.

The blending amount of the plasticizer (E) with respect to 100 parts by mass of the polyvinyl chloride resin (A) is preferably 1 to 40 parts by mass. By setting the compounding amount of the plasticizer (E) to 1 part by mass or more, surging can be prevented when producing a foamed resin sheet, and stable sheet film formation is possible. On the other hand, when the compounding amount of the plasticizer (E) is 40 parts by weight or less, the plasticizer from the foamed resin sheet can have sufficient moldability and processability without bleeding out. Further, more preferable flame retardant performance can be imparted without deteriorating the flame retardant performance.
The lower limit of the compounding amount of the plasticizer (E) is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more. Further, the upper limit of the amount of the plasticizer (E) compounded is preferably 35 parts by mass or less, and more preferably 30 parts by mass or less.

  The resin composition for a foamed resin sheet of the present invention includes a stabilizer, an antioxidant, an ultraviolet absorber, a light stabilizer, an antibacterial / antifungal agent, an antistatic agent, and a lubricant within a range that does not impair the effects of the present invention. It may also contain additives such as pigments, dyes and the like.

[Foam resin sheet]
The foamed resin sheet of the present invention is a foamed resin sheet obtained by thermoforming the above resin composition for a foamed resin sheet, wherein the thermal expansion microcapsules thermally expanded by heat applied during the thermoforming ( C).

  The foamed resin sheet is composed of a matrix and cells. The matrix contains the above-mentioned polyvinyl chloride resin (A) and phosphorus flame retardant (B), and in some cases, the ethylene copolymerized polyvinyl chloride resin (D), plasticizer (E), flame retardant It may contain a fuel aid (F). The content ratio of each component is as described above.

  The bubbles are formed by thermal expansion of the thermal expansion microcapsules when the resin composition for a foamed resin sheet is thermoformed. Since the shell constituting the thermally expanded microcapsule is not destroyed by thermal expansion, it means that the shell exists in an expanded state between the cells and the matrix. Further, each bubble exists in the matrix in an independent state. Further, in the bubbles of the present invention, a volatile liquid may remain inside the shell after the sheet is cooled, and such a case is also meant to be included as bubbles.

  The particle diameter of the thermal expansion microcapsules (C) used in the resin composition for a foamed resin sheet is 5 to 50 μm, preferably 10 to 40 μm, and this expands due to heat during molding, and in the resulting foamed sheet, The bubbles are 60 to 200 μm, preferably 80 to 150 μm.

  The foamed resin sheet of the present invention preferably has a tensile elongation at break measured according to JIS K7127 of 50% or more, more preferably 60% or more, further preferably 80% or more, particularly preferably 100% or more. By setting the tensile elongation at break to 50% or more, it is possible to prevent breakage of the sheet when it is used as a building material such as floor material or wall material, for example, when a foamed resin sheet is attached to plywood or the like. .

The density of the foamed resin sheet of the present invention is preferably 0.10~0.90g / cm ^3, more preferably 0.15~0.85g / cm ^3, 0.15~0 More preferably, it is 0.80 g / cm ³ . By setting the density of the foamed resin sheet to 0.10 g / cm ³ or more, excessive reduction in strength of the sheet can be suppressed. On the other hand, by setting the density of the foamed resin sheet to 0.90 g / cm ³ or less, it is possible to reduce the weight of the sheet, and in the foamed resin sheet, the proportion of air having a lower thermal conductivity than that of the resin is usually occupied. By increasing the value, the heat insulating property can be improved. The above density is an apparent density measured according to JIS K7222 (2005).

The foamed resin sheet of the present invention preferably has a thermal conductivity of 0.1 W / m · K or less, and more preferably 0.09 W / m · K or less. Here, the thermal conductivity can be calculated by the equation (1) by measuring the thermal diffusivity, the specific heat capacity and the apparent density of the foamed resin sheet.
λ = α × Cp × ρ (1) Formula λ: Thermal conductivity (W / m · K)
α: thermal diffusivity (measured according to JIS R1611 (2010))
Cp: Specific heat capacity (measured according to JIS K7123 (2012))
ρ: Apparent density (measured according to JIS K7222 (2005))

[Method for producing foamed resin sheet]
The method for producing the foamed resin sheet of the present invention is not particularly limited, but it can be obtained by thermoforming the resin composition for a foamed resin sheet. The raw material of the foamed resin sheet composition is blended with a stirrer, and the molten resin for the foamed resin sheet is kneaded in a heated and molten state by using a known kneading machine such as a Banbury mixer, a single-screw extruder, a roll, and a kneader. Obtain the composition. The melting temperature of the resin composition for a foamed resin sheet is appropriately determined according to the type of resin, the mixing ratio, the presence or absence of additives, and the type, but the lower limit of the melting temperature is, for example, 150 ° C. or higher, preferably 170 ° C. Above, the upper limit of the melting temperature is, for example, 220 ° C. or lower, preferably 200 ° C. or lower. By molding within such a melting temperature range, a foamed resin sheet having a good appearance can be molded without causing thermal deterioration of the polyvinyl chloride resin.

  A molten resin composition is obtained by melt-kneading the resin composition for a foamed resin sheet. Next, the foamed resin sheet can be obtained by molding the obtained molten resin composition for a foamed resin sheet into a sheet shape with a calendar roll or a T-die molding machine.

  In extrusion molding, for example, a molten resin composition is extrusion-molded using a mold such as a T die. To cool the extruded molten resin composition, for example, the molten resin composition is brought into contact with a cooled cooler such as a cast roll and rapidly cooled. As a result, the molten resin composition is solidified and a non-stretched sheet is obtained. The cooling temperature is not limited as long as it is lower than the melting temperature, but the upper limit of the cooling temperature is, for example, 90 ° C. or lower, preferably 60 ° C. or lower, and the lower limit of the cooling temperature is, for example, 0 ° C. or higher, preferably Is 10 ° C. or higher.

  The unstretched sheet is a sheet that is not stretched positively for the purpose of increasing the strength of the sheet, but here, a sheet stretched to less than 2 times by a stretching roll during extrusion molding is also included in the unstretched sheet. .

The thickness of the foamed resin sheet of the present invention is not particularly limited, but can be appropriately set depending on the intended use. Generally, it is preferably 15 mm or less, more preferably 10 mm or less, and further preferably 7 mm or less. Further, it is preferably 0.5 mm or more, more preferably 1 mm or more, further preferably 2 mm or more, and particularly preferably 2.5 mm or more.
By setting the thickness of the foamed resin sheet within the above range, workability of winding the sheet into a roll becomes more excellent and efficient production becomes possible. In addition, flame retardancy and other physical property values can be made more preferable.
Moreover, the foamed resin sheet of the present invention may be a single layer or a multilayer.

[Laminated sheet]
Another aspect of the present invention is a laminated sheet containing at least one layer of the foamed resin sheet of the present invention, and more preferably a laminated sheet having the foamed resin sheet of the present invention as an intermediate layer.

  The foamed resin sheet of the present invention can be used as an intermediate layer, and a polyvinyl chloride resin (A) or another resin can be used to form a laminated sheet. For example, a polyvinyl chloride resin (A) layer can be provided on the front surface layer and / or the back surface layer of the foamed resin sheet.

  When the foamed resin sheet of the present invention is used, for example, in an application requiring excellent appearance performance on the sheet surface, by providing a polyvinyl chloride resin (A) layer on the surface layer, the appearance of the foamed resin sheet can be improved. It is possible to suppress defects.

  In this case, it is particularly preferable that the surface layer and / or the back surface layer of the laminated sheet do not contain the thermal expansion microcapsules (C). It should be noted that "not containing thermal expansion microcapsules" also includes containing a very small amount such that the appearance is not impaired by the foaming action of the thermal expansion microcapsules.

  Further, when a foamed resin sheet is used as an intermediate layer and a polyvinyl chloride resin (A) or another resin is used to form a laminated sheet, a phosphorus-based flame retardant (B) or a flame retardant suitable for another resin is used. It is preferably contained in the front / back surface layer. With such a configuration, flame retardancy can be further improved. The blending amount of the flame retardant in the front / back surface layer is preferably 20 to 55 parts by mass, more preferably 25 to 50 parts by mass, relative to 100 parts by mass of the base material such as the polyvinyl chloride resin (A). Parts, and more preferably 30 to 45 parts by mass.

  The foamed resin sheet of the present invention may have a primer layer formed on one side and / or both sides as necessary.

  The resin foam sheet of the present invention may be provided with another resin layer depending on weather resistance and other necessary purposes. This resin layer can be formed by laminating or coating a polyolefin resin, a polyester resin, an acrylic resin, a urethane resin, or the like. Further, the resin layer can be embossed.

As a method for producing a laminated sheet using the foamed resin sheet of the present invention, (1) a method of previously preparing a foamed resin sheet and other film layers, and then laminating the foamed resin sheet and other film layers, ( 2) A method of directly forming the foamed resin sheet and another film layer can be mentioned.
In the case of the method (1), an extrusion laminating method in which a foamed resin sheet and other film layers are extruded and laminated by a pressure roll can be used.
In the case of the method (2), the foamed resin sheet and the other film layer can be prepared by an extrusion molding method such as a T-die extrusion molding method, an inflation molding method and a calender molding method.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples and Comparative Examples. The numerical values of the examples shown below can be replaced with the numerical values (that is, the upper limit value or the lower limit value) described in the above embodiment.

[Materials used]
<Polyvinyl chloride resin (A)>
As the polyvinyl chloride resin (A), a trade name "TH-1000" (average degree of polymerization: 1050) manufactured by Taiyo PVC Co., Ltd. was used.

<Phosphorus flame retardant (B)>
As the phosphorus-based flame retardant (B), the product name “Reophos” manufactured by Ajinomoto Fine-Techno Co., Inc. was used.

<Thermal expansion microcapsule (C)>
As the thermal expansion microcapsules (C), "EXPANCEL 930DU120" (expansion start temperature: 122 to 132 ° C) manufactured by Akzo Nobel was used.

<Ethylene copolymerized polyvinyl chloride resin (D)>
As the ethylene-copolymerized polyvinyl chloride resin (D), a trade name “TE-1050” (average degree of polymerization: 1050, ethylene content: 1.3% by mass) manufactured by Taiyo PVC Co., Ltd. was used.

<Plasticizer (E)>
As the plasticizer (E-1), a trade name “DOP” (dioctyl phthalate) manufactured by J-Plus was used.
As the plasticizer (E-2), a trade name “O-130P” (epoxidized soybean oil) manufactured by ADEKA was used.

<Flame retardant aid (F)>
Antimony trioxide was used as the flame retardant aid (F).

<Stabilizer (G)>
As the stabilizer (G), ADEKA's trade name "ADEKA STAB" (Ba-Zn stabilizer) was used.

[Evaluation methods]
The foamed resin sheets of Examples and Comparative Examples were evaluated by the following methods. Here, the flow direction in which the foamed resin sheet is extruded from the T-die is the vertical direction, and the orthogonal direction is the horizontal direction.

(1) Density and thermal conductivity The thermal diffusivity, the specific heat capacity and the apparent density of the obtained foamed resin sheet were measured, and the thermal conductivity was calculated by the equation (1). If the density is 0.90 g / cm ³ or less, it can be said that the lightweight property is excellent. If the thermal conductivity is 0.1 W / m · K or less, it can be said that the heat insulating property is excellent.
λ = α × Cp × ρ (1) Formula λ: Thermal conductivity (W / m · K)
α: thermal diffusivity (measured according to JIS R1611 (2010))
Cp: Specific heat capacity (measured according to JIS K7123 (2012))
ρ: Apparent density (measured according to JIS K7222 (2005))

(2) Tensile rupture elongation In the longitudinal direction of the obtained foamed resin sheet, a dumbbell test piece with a measuring portion having a width of 10 mm was used, and according to JIS K7127, a temperature was 23 ° C., a chuck distance was 40 mm, and a pulling speed was 300 mm / min. The measurement was performed under the conditions of, and the tensile elongation at break (%) was calculated. If the tensile elongation at break is 50% or more, it can be said that the mechanical properties are excellent.

(3) Sheet appearance Visually observe the appearance of the obtained foamed resin sheet, "○" indicates that the surface is smooth and good, "△" indicates that the surface is almost smooth and almost good, and plate out Those whose surface was rough due to things etc. were marked as "x". If this evaluation is “◯” or “Δ”, it can be said that the moldability is excellent.

<Measurement of flame retardancy>
[Fire Defense Law flameproof standard]
The foamed resin sheet thus obtained was used, and in accordance with JIS L1091 fire protection standard, a test piece of 350 mm × 250 mm was used, and measurement was carried out using a 45 ° flammability tester. When the apparent density of the foamed resin sheet was 0.45 g / cm ³ or more, a Meckel burner was used, and the afterflame time was 5 seconds or less, the residual dust time was 20 seconds or less, and the carbonization area was 40 cm ² or less. When the apparent density of the foamed resin sheet was less than 0.45 g / cm ^3, a micro burner was used, and afterflame time was 3 seconds or less, residual dust time was 5 seconds or less, and carbonization area was 30 cm ² or less.
[UL94 standard]
Using the obtained foamed resin sheet, the UL94V test (20 mm vertical burning test) was measured on a 125 mm × 13 mm test body according to the UL94 standard, and the obtained result was evaluated as V-0 according to the flammability criterion. , V-1, V-2 and failed.
Table 1 shows each measurement result.

(Examples and comparative examples)
Raw materials adjusted to have the blending ratio shown in Table 1 were blended using a Henschel mixer, and the resulting mixture was put into a Φ40 mm single-screw extruder equipped with a T-die at a resin temperature of 180 ° C. The foamed resin sheets according to Examples and Comparative Examples were obtained by extrusion molding so as to have a thickness (2 mm, 4 mm).
The obtained sheet was evaluated by the above evaluation method. The results are shown in Table 1.

[result]
From Table 1, all of the foamed resin sheets according to Examples 1 and 2 have a low density, the thermal conductivity and the tensile elongation at break satisfy the standard values, the sheet appearance is good, and the flame retardant performance is satisfied. Met. From this, it was confirmed that the foamed resin sheet of the present invention was excellent in lightness, heat insulation, mechanical properties, moldability and flame retardancy.
On the other hand, the sheet according to Comparative Example 1 in which only the flame retardant aid (F), antimony trioxide, was used instead of the phosphorus-based flame retardant (B) had a poor appearance and poor flame retardancy. The sheet according to Comparative Example 2 in which the phthalic acid-based plasticizer (E-1) was used instead of the phosphorus-based flame retardant (B) and the tensile strength and elongation were increased to the level of Example 1 was inferior in flame retardancy. there were.

  Since the foamed resin sheet of the present invention is excellent in heat insulation, lightness, mechanical properties, and flame retardancy, it is used in applications requiring light weight, heat insulation, sound insulation, and vibration isolation, such as flooring materials for building materials, wall materials, and doors. It can be used as a window frame or the like, a heat insulating material for a vehicle member, a sound insulating material, or the like.

Claims (11)

  Foaming characterized by containing 20 to 55 parts by mass of the phosphorus flame retardant (B) and 1 to 20 parts by mass of the thermal expansion microcapsule (C) with respect to 100 parts by mass of the polyvinyl chloride resin (A). A resin composition for a resin sheet.   The resin composition for a foamed resin sheet according to claim 1, wherein the phosphorus-based flame retardant (B) is an aromatic phosphate ester-based flame retardant.   Furthermore, 1-30 mass parts of ethylene-copolymerization polyvinyl chloride resin (D) is contained with respect to 100 mass parts of said polyvinyl chloride-type resin (A), The foaming of Claim 1 or 2 characterized by the above-mentioned. A resin composition for a resin sheet.   A foamed resin sheet obtained by thermoforming the resin composition for a foamed resin sheet according to any one of claims 1 to 3, wherein the thermal expansion is caused by the heat applied during the thermoforming. A foamed resin sheet having microcapsules (C). Into a matrix containing 20 to 55 parts by mass of a phosphorus-based flame retardant (B) with respect to 100 parts by mass of a polyvinyl chloride resin (A), closed cells caused by thermal expansion microcapsules (C) are formed. A foamed resin sheet having an apparent density of 0.10 to 0.90 g / cm ³ .   The foamed resin sheet according to claim 5, wherein the closed cells caused by the thermally expanded microcapsules (C) are thermally expanded thermally expanded microcapsules.   The foamed resin sheet according to any one of claims 4 to 6, wherein the tensile elongation at break measured according to JIS K7127 is 50% or more.   The foamed resin sheet according to claim 4, which has a thermal conductivity of 0.1 W / m · K or less.   A laminated sheet comprising at least one layer of the foamed resin sheet according to any one of claims 4 to 8.   The laminated sheet according to claim 9, wherein the foamed resin sheet is provided in at least an intermediate layer.   A step of thermoforming the resin composition for a foamed resin sheet according to any one of claims 1 to 3, wherein the thermal expansion microcapsules (C) are expanded by heat applied during the thermoforming. Method for manufacturing foamed resin sheet.