WO2018079261A1

WO2018079261A1 - Polypropylene-based resin composition for foam molding, polypropylene-based foam molded body, polypropylene-based multilayer foam molded body, and production method for polypropylene-based foam molded body

Info

Publication number: WO2018079261A1
Application number: PCT/JP2017/036833
Authority: WO
Inventors: 智也又吉; 孝行渡辺; 江里口　真男
Original assignee: 三井化学東セロ株式会社
Priority date: 2016-10-31
Filing date: 2017-10-11
Publication date: 2018-05-03
Also published as: JPWO2018079261A1; JP6790110B2

Abstract

This polypropylene-based resin composition for foam molding includes a polypropylene-based resin and an inorganic filler. The inorganic filler includes at least one type selected from talc or silica and the inorganic filler water content is no more than 0.10% by mass of the whole inorganic filler.

Description

Polypropylene resin composition for foam molding, polypropylene foam molded article, polypropylene multilayer foam molded article, and method for producing polypropylene foam molded article

The present invention relates to a polypropylene resin composition for foam molding, a polypropylene foam molded article, a polypropylene multilayer foam molded article, and a method for producing a polypropylene foam molded article.

Wooden boards such as hardboards and medium density fiberboards are used as, for example, building materials, furniture, partitioning materials, heat insulating materials, packing materials and the like because they are lightweight and have excellent mechanical properties.

Examples of the technology related to such a wood board include those described in Patent Document 1 (Japanese Patent Laid-Open No. 2014-151599) and Patent Document 2 (Japanese Patent Laid-Open No. 2010-64306).

Patent Document 1 includes a wood board formed by adhering a wood chip or wood fiber with an adhesive, and containing a parenchyma-removed bamboo fiber obtained by removing parenchyma cells from bamboo fiber obtained by crushing bamboo. The characteristic wood board is described.

Patent Document 2 discloses a wood board obtained by hot pressing a wood material together with an adhesive. The wood board is made of a fine powder of sodium sulfite having an average particle size of 40 μm or more and 180 μm or less. A wood board characterized by containing 0.1 to 30% by weight based on the dry weight is described.

JP 2014-151599 A JP 2010-64306 A

From the viewpoint of protecting the global environment, it is expected that deforestation will be suppressed and it will be difficult to obtain timber resources, so an alternative to wood boards is required.
The present inventors examined using a polypropylene foam sheet containing a polypropylene resin and an inorganic filler as an alternative to the wooden board. However, it has been clarified that the polypropylene foam sheet containing the polypropylene resin and the inorganic filler may have uneven appearance such as color unevenness and vertical stripes (flow pattern) on the surface, which may deteriorate the appearance. .

The present invention has been made in view of the above circumstances, and has an excellent appearance and can be used as a substitute for a wooden board. A polypropylene foam molded article and a polypropylene for foam molding that can realize a polypropylene multilayer foam molded article. A resin composition is provided.

The present inventors diligently studied to realize a polypropylene-based foam molded product and a polypropylene-based multilayer foamed molded product that have an excellent appearance and can be used as a substitute for a wooden board. As a result, the present inventors have a resin composition in which an inorganic filler having a moisture content of a specific value or less is blended with a polypropylene resin, has an excellent appearance, and can be used as a substitute for a wooden board. It has been found that a polypropylene-based foam molded body and a polypropylene-based multilayer foam molded body can be realized.

That is, according to the present invention, the following polypropylene molding resin composition for foam molding, a polypropylene foam molding, a polypropylene multilayer foam molding, and a method for producing a polypropylene foam molding are provided.

[1]
A polypropylene resin composition for foam molding containing a polypropylene resin and an inorganic filler,
The inorganic filler contains at least one selected from talc and silica,
A polypropylene resin composition for foam molding in which the water content of the inorganic filler is 0.10% by mass or less based on the whole inorganic filler.
[2]
In the polypropylene resin composition for foam molding according to the above [1],
A polypropylene resin composition for foam molding, wherein the inorganic filler contains talc.
[3]
In the polypropylene resin composition for foam molding according to the above [1] or [2],
Polypropylene for foam molding in which the content of the inorganic filler in the polypropylene resin composition is 5 parts by mass or more and 90 parts by mass or less when the total amount of the polypropylene resin and the inorganic filler is 100 parts by mass. Resin composition.
[4]
In the polypropylene resin composition for foam molding according to any one of the above [1] to [3],
The total content of the polypropylene resin and the inorganic filler in the polypropylene resin composition for foam molding is 50% by mass or more and 100% when the total of the polypropylene resin resin composition for foam molding is 100% by mass. A polypropylene-based resin composition for foam molding, having a mass% or less.
[5]
In the polypropylene resin composition for foam molding according to any one of the above [1] to [4],
In accordance with ASTM D1238, the polypropylene resin composition for foam molding, wherein the melt flow rate of the polypropylene resin measured at 230 ° C. and a load of 2.16 kg is from 0.5 g / 10 min to 20 g / 10 min. .
[6]
In the polypropylene resin composition for foam molding according to any one of the above [1] to [5],
A polypropylene resin composition for foam molding, wherein the polypropylene resin has a Z average molecular weight (Mz) / weight average molecular weight (Mw) of 7 to 20 as measured by gel permeation chromatography (GPC).
[7]
A polypropylene-based foam-molded article comprising the foam-molded polypropylene-based resin composition according to any one of [1] to [6].
[8]
In the polypropylene-based foam molded article according to the above [7],
A polypropylene foam molded article having a density of the polypropylene foam molded article of 1.0 g / cm ³ or less.
[9]
In the polypropylene-based foam molded article according to the above [7] or [8],
A polypropylene foam molded article having a flexural modulus of 1.0 GPa or more of the polypropylene foam molded article measured in an environment of 23 ° C. and 50% RH.
[10]
In the polypropylene foam molded article according to any one of [7] to [9] above,
The polypropylene-based foamed molded article measured under the conditions of 23 ° C. and 50% RH, and under the conditions of specimen shape: strip shape, specimen width: 10 mm, distance between chucks: 50 mm, and tensile speed: 20 mm / min. A polypropylene-based foamed molded article having a Young's modulus of 0.3 GPa or more.
[11]
In the polypropylene foam molded article according to any one of the above [7] to [10],
A polypropylene foam molded article having an arithmetic average roughness Ra of 2.5 μm or less on the surface of the polypropylene foam molded article, measured according to JIS-B0601-1994.
[12]
In the polypropylene-based foam molded article according to any one of [7] to [11] above,
A polypropylene-based foamed molded product having a thickness of from 0.5 mm to 30 mm.
[13]
In the polypropylene-based foam molded article according to any one of [7] to [12] above,
Polypropylene foam molded body used as an alternative to wood boards.
[14]
A polypropylene foam layer composed of the polypropylene foam molded article according to any one of the above [7] to [13];
A first non-foaming resin layer provided on one surface of the polypropylene-based foam layer and containing a thermoplastic resin and an inorganic filler;
A second non-foaming resin layer provided on the other surface of the polypropylene-based foam layer and containing a thermoplastic resin and an inorganic filler;
A polypropylene-based multilayer foamed molded article.
[15]
In the polypropylene-based multilayer foamed molded article according to the above [14],
A polypropylene-based multilayer foamed molded article, wherein the first non-foamable resin layer and the second non-foamable resin layer each have a thickness of 0.05 mm to 5 mm.
[16]
In the polypropylene-based multilayer foamed molded article according to the above [14] or [15],
The ratio of the thickness of the first non-foamable resin layer to the thickness of the entire polypropylene-based multilayer foamed molded article is 0.01 or more and 0.5 or less,
A polypropylene-based multilayer foamed molded article, wherein a ratio of the thickness of the second non-foamable resin layer to the thickness of the entire polypropylene-based multilayer foamed molded article is 0.01 or more and 0.5 or less.
[17]
In the polypropylene-based multilayer foamed molded article according to any one of the above [14] to [16],
A polypropylene-based multilayer foamed molded article, wherein the inorganic filler in the first non-foamable resin layer and the second non-foamable resin layer includes one or more selected from talc, mica, and silica, respectively.
[18]
In the polypropylene-based multilayer foamed molded article according to any one of the above [14] to [17],
The thermoplastic resin in which the content of the inorganic filler in the first non-foamable resin layer and the second non-foamable resin layer is included in the first non-foamable resin layer and the second non-foamable resin layer. A polypropylene-based multilayer foamed molded article that is 5 parts by mass or more and 90 parts by mass or less when the total amount of the resin and the inorganic filler is 100 parts by mass.
[19]
In the polypropylene-based multilayer foamed molded article according to any one of the above [14] to [18],
The first non-foamable resin layer and the second non-foamable resin layer have the same composition and have the same thickness, and are a polypropylene-based multilayer foamed molded article.
[20]
In the polypropylene-based multilayer foamed molded article according to any one of the above [14] to [19],
Polypropylene-based multilayer foamed molding used as an alternative to wood boards.
[21]
A production method for producing a polypropylene-based foamed molded article comprising a polypropylene-based resin and an inorganic filler,
The inorganic filler contains at least one selected from talc and silica,
Adjusting the moisture content of the inorganic filler to 0.10% by mass or less based on the whole inorganic filler by heating the inorganic filler;
A step of foam-molding a polypropylene-based resin composition containing the inorganic filler and a polypropylene-based resin, wherein the obtained moisture content is 0.10% by mass or less;
The manufacturing method of the polypropylene-type foaming molding containing this.

According to the present invention, it is possible to realize a polypropylene-based foam molded product and a polypropylene-based multilayer foamed molded product that have excellent appearance and can be used as a substitute for a wooden board.

The above-described object and other objects, features, and advantages will be further clarified by a preferred embodiment described below and the following drawings attached thereto.

It is sectional drawing which showed typically an example of the structure of the polypropylene-type foaming molding of embodiment which concerns on this invention. It is sectional drawing which showed typically an example of the structure of the polypropylene type multilayer foaming molding of embodiment which concerns on this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The numerical range “A to B” represents A or more and B or less unless otherwise specified.

1. About Polypropylene Resin Composition for Foam Molding The polypropylene resin composition for foam molding according to this embodiment includes a polypropylene resin and an inorganic filler. And the said inorganic filler contains at least 1 type selected from a talc and a silica, and the moisture content of the said inorganic filler is 0.10 mass% or less with respect to the said whole inorganic filler.

In addition, the water content of the inorganic filler according to this embodiment is preferably 0.08% by mass or less, more preferably 0.07% by mass or less, still more preferably 0.06% by mass or less, particularly with respect to the entire inorganic filler. Preferably it is 0.05 mass% or less. Although the minimum of the moisture content rate of the inorganic filler which concerns on this embodiment is not specifically limited, For example, it is 0.001 mass% or more with respect to the whole inorganic filler.
Here, the moisture content of the inorganic filler can be calculated, for example, by quantifying the moisture generated by heating the inorganic filler in a nitrogen stream and by the Karl Fischer coulometric titration method.

As described above, from the viewpoint of protecting the global environment, it is expected that deforestation will be suppressed and it will become difficult to obtain wood resources, so an alternative to wood boards is required.
The present inventors examined using a polypropylene foam sheet containing a polypropylene resin and an inorganic filler as an alternative to the wooden board. However, it has been clarified that the polypropylene foam sheet containing the polypropylene resin and the inorganic filler may have uneven appearance such as color unevenness and vertical stripes (flow pattern) on the surface, which may deteriorate the appearance. .
Therefore, the present inventors have intensively studied to realize a polypropylene-based foam molded product and a polypropylene-based multilayer foamed molded product that are excellent in appearance and can be used as a substitute for a wooden board. As a result, the present inventors have a resin composition in which an inorganic filler having a moisture content of a specific value or less is blended with a polypropylene resin, has an excellent appearance, and can be used as a substitute for a wooden board. It has been found that a polypropylene-based foam molded body and a polypropylene-based multilayer foam molded body can be realized.
In other words, when an inorganic filler having a moisture content of not more than the above upper limit is used, the occurrence of unevenness such as gloss unevenness, color unevenness and vertical stripes (flow pattern) on the surface is suppressed, and the uniformity of the foamed cells is further improved. Therefore, it is possible to obtain a polypropylene-based foam molded article having an excellent appearance.
The inorganic filler having a moisture content of not more than the above upper limit value is, for example, obtained by heating the inorganic filler at 80 to 150 ° C. for about 0.5 to 48 hours using a dehumidifying dryer or a vacuum dryer. It can be obtained by removing moisture adsorbed inside.

Furthermore, according to the polypropylene resin composition for foam molding according to the present embodiment, by containing at least one selected from talc and silica as the inorganic filler, for example, compared with the case where calcium carbonate is used as the inorganic filler, etc. Thus, it is possible to reduce the weight of the resulting polypropylene-based foamed molded article.
Moreover, according to the polypropylene resin composition for foam molding according to the present embodiment, by containing at least one selected from talc and silica as the inorganic filler, for example, compared with the case where glass fiber is used as the inorganic filler, etc. The appearance of the polypropylene-based foamed molded product can be improved.

In addition, since glass fiber is fluffy, it is difficult to handle, and further, the glass fiber is exposed on the surface and end of the molded body, and the appearance of the molded body may be deteriorated.
In addition, since the polypropylene resin composition for foam molding according to the present embodiment uses a polypropylene resin that is a plastic, the resulting polypropylene foam molded article has excellent water resistance compared to a wooden board and is wet with water. Excellent mechanical properties can be maintained even when left in a humid environment for a long time. In addition, the polypropylene-based foam-molded article composed of the foam-molded polypropylene-based resin composition according to the present embodiment is unlikely to be chipped like a wood board and is excellent in handleability.

The total content of the polypropylene resin and the inorganic filler in the polypropylene resin composition for foam molding according to the present embodiment is preferably 50% by weight or more when the entire polypropylene foam molded body 100 is 100% by weight. 100 mass% or less, More preferably, it is 70 mass% or more and 100 mass% or less, More preferably, it is 90 mass% or more and 100 mass% or less, Most preferably, it is 95 mass% or more and 100 mass% or less. As a result, a polypropylene-based foamed molded article having an excellent balance of lightness, mechanical properties, recyclability, handleability, appearance, moldability, moisture resistance, and the like can be obtained.

Hereinafter, each component constituting the polypropylene resin composition for foam molding will be described.

<Polypropylene resin>
The polypropylene resin composition for foam molding according to the present embodiment contains a polypropylene resin as an essential component.
Examples of the polypropylene resin according to the present embodiment include a propylene homopolymer, a copolymer of propylene and ethylene or an α-olefin having 4 to 20 carbon atoms. Examples of the α-olefin having 4 to 20 carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, Examples include 1-hexadecene, 1-octadecene, 1-eicosene and the like. Among these, ethylene or an α-olefin having 4 to 10 carbon atoms is preferable, and ethylene is more preferable. These α-olefins may form a random copolymer with propylene or may form a block copolymer. The content of structural units derived from these α-olefins is preferably 5 mol% or less, more preferably 2 mol% or less in the polypropylene resin. The polypropylene resin in the polypropylene resin composition for foam molding may be used alone or in combination of two or more.
Among these, a propylene homopolymer is preferable as the polypropylene resin from the viewpoint of obtaining a polypropylene-based foam molded article having higher rigidity.

The polypropylene resin according to the present embodiment can be manufactured by various methods. For example, it can be produced using a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst.

The melt flow rate (MFR) of the polypropylene resin according to this embodiment measured under conditions of 230 ° C. and 2.16 kg load in accordance with ASTM D1238 is preferably 0.5 g from the viewpoint of fluidity and moldability. / 10 minutes or more, more preferably 1 g / 10 minutes or more. From the viewpoint of further stabilizing the moldability and further suppressing foam breakage of the foamed cells, preferably 20 g / 10 minutes or less, more preferably 10 g / 10. Min. Or less, more preferably 7 g / 10 min or less.

From the viewpoint of high melt tension and melt elongation and excellent moldability, the polypropylene resin according to this embodiment has a Z average molecular weight (Mz) / weight average molecular weight (Mw) measured by gel permeation chromatography (GPC). Preferably they are 7 or more and 20 or less, More preferably, they are 10 or more and 20 or less.
Polypropylene resins having a Mz / Mw value within the above range show a wide molecular weight distribution and contain a large amount of high molecular weight components. Therefore, the melt tension and melt elongation are high, and the moldability including foaming is excellent. Therefore, by using a polypropylene resin having an Mz / Mw value within the above range, the foam moldability of the polypropylene resin composition for foam molding can be improved. Even if the inorganic filler is highly filled, foaming is possible. Cell uniformity can be made better, and perforation and sheet breakage of the polypropylene-based foamed molded product can be further suppressed. As a result, a polypropylene-based foamed molded product that is superior in appearance can be realized.
The content of the polypropylene resin having an Mz / Mw value within the above range is preferably 50% by mass or more when the total amount of the polypropylene resin contained in the polypropylene resin composition for foam molding is 100% by mass. Preferably it is 60 mass% or more.

<Inorganic filler>
The polypropylene resin composition for foam molding according to this embodiment contains an inorganic filler as an essential component.
The inorganic filler includes at least one selected from talc and silica from the viewpoint of obtaining a polypropylene-based foam-molded article excellent in lightness, mechanical properties, recyclability, handleability and appearance. Among these, talc is preferable from the viewpoints of compatibility with polypropylene resin, foamability, moldability, colorability, low cost, safety, and the like.

The content of the inorganic filler in the polypropylene resin composition for foam molding according to the present embodiment is preferably 5 parts by mass or more when the total amount of the polypropylene resin and the inorganic filler is 100 parts by mass. The amount is preferably 15 parts by mass or more, more preferably 25 parts by mass or more, still more preferably 35 parts by mass or more, and particularly preferably 45 parts by mass or more.
Further, the content of the inorganic filler in the polypropylene resin composition for foam molding according to the present embodiment is preferably 90 parts by mass or less when the total amount of the polypropylene resin and the inorganic filler is 100 parts by mass. More preferably, it is 80 mass parts or less, More preferably, it is 70 mass parts or less, Most preferably, it is 65 mass parts or less.

By making the content of the inorganic filler more than the above lower limit value, it is possible to further improve mechanical properties such as bending properties and tensile properties, heat resistance, moisture resistance, dimensional stability, etc. of the obtained polypropylene-based foam molded article. it can.
Moreover, by making the content of the inorganic filler not more than the above upper limit value, the balance of light weight and high rigidity of the obtained polypropylene foam molded article can be improved, and the moldability and foam cell of the polypropylene foam molded article can be improved. The uniformity of the resin can be further improved, and the perforation and sheet breakage of the polypropylene-based foam molded product can be further suppressed. As a result, a polypropylene-based foam molded product that is more excellent in appearance can be realized. .

In addition, the inorganic filler may be used without treatment, in order to improve the interfacial adhesion with the polypropylene resin and improve the dispersibility with respect to the polypropylene resin, a silane coupling agent, a titanium coupling agent, The surface may be treated with a surfactant or the like.

<Other ingredients>
The polypropylene resin composition for foam molding according to the present embodiment includes a heat stabilizer, an antioxidant, an ultraviolet absorber, a pigment, an antistatic agent, a copper damage inhibitor, a flame retardant, a neutralizing agent, if necessary. Foaming agent, plasticizer, nucleating agent, anti-bubble agent, crosslinking agent, weathering stabilizer, light stabilizer, anti-aging agent, fatty acid metal salt, softener, dispersant, colorant, lubricant, natural oil, synthetic oil, You may mix | blend additives, such as wax.

2. FIG. 1 is a cross-sectional view schematically showing an example of the structure of a polypropylene foam molded body 100 according to an embodiment of the present invention.
The polypropylene-based foam molded body 100 according to the present embodiment is constituted by the above-described polypropylene-based resin composition for foam molding according to the present embodiment, and can be obtained by foam-molding the polypropylene-based resin composition for foam molding. . Although the shape of the polypropylene-type foaming molding 100 which concerns on this embodiment is not specifically limited, For example, it is a sheet form.

The density of the polypropylene-based foamed molded article 100 is preferably 1.0 g / cm ³ or less, less than 1.0 g / cm ³ is more preferable. When the density is not more than the above upper limit value or less than the above upper limit value, an even lighter polypropylene-based foam molded article 100 can be obtained. Moreover, since a polypropylene-type foaming molding can float in water as a density is below the said upper limit or less, it becomes easy to fractionate a structural component and can improve recyclability.
The density of the polypropylene-based foamed molded article 100 is preferably 0.35 g / cm ³ or more, 0.40 g / cm ³ or more, more preferably, 0.45 g / cm ³ or more and more preferably, 0.50 g / cm ³ or more Is particularly preferred. When the density is equal to or higher than the lower limit, mechanical properties such as bending properties and tensile properties of the polypropylene foamed molded product 100 can be further improved.
The density of the polypropylene-based foam molded body 100 is controlled within the above range by appropriately controlling, for example, the type and blending amount of the polypropylene-based resin, inorganic filler, and the like, and the expansion ratio of the polypropylene-based foam molded body 100, respectively. be able to.

The flexural modulus of the polypropylene foam molded body 100 according to this embodiment measured in an environment of 23 ° C. and 50% RH is preferably 1.0 GPa or more, more preferably 1.5 GPa or more, and further 2.0 GPa or more. Preferably, 2.5 GPa or more is even more preferable, and 3.0 GPa or more is particularly preferable.
By setting the flexural modulus to the above lower limit or more, the rigidity of the polypropylene foam molded body 100 can be further improved. As a result, deformation of the polypropylene foam molded body 100 with respect to external stress can be suppressed, or It is possible to improve the scratch resistance, heat resistance, dimensional stability, etc. of the foam molded body 100.
Moreover, 10 GPa or less is preferable and, as for the bending elastic modulus of the polypropylene-type foaming molding 100 which concerns on this embodiment, 9 GPa or less is more preferable.
By setting the flexural modulus to be equal to or less than the above upper limit value, the balance between the deformation resistance against external stress and the toughness of the polypropylene foam molded body 100 can be improved.
Here, the bending elastic modulus of the polypropylene-based foam molded body 100 can be measured by a three-point bending test. For example, with reference to the bending strength test described in JIS A5905, the specimen thickness t: 3 mm, specimen width b: 50 mm, specimen length: 150 mm, and span in an environment of 23 ° C. and 50% RH The amount of deflection Y [mm] with respect to the test load F [N] is measured under the conditions of the distance L: 100 mm and the bending speed: 50 mm / min. The gradient ΔF / ΔY of the initial straight line portion in the obtained load-deflection diagram is obtained, and the flexural modulus: E [GPa] is obtained from the following equation (1).
E = {L ³ / (4b · t ³ )} · (ΔF / ΔY) (1)
One point is measured for each of the MD direction and the TD direction, and the average value thereof can be adopted as the bending elastic modulus.
The flexural modulus of the polypropylene-based foam molded body 100 is within the above range by appropriately controlling, for example, the type and blending amount of the polypropylene-based resin, inorganic filler, and the like, and the expansion ratio of the polypropylene-based foam molded body 100, respectively. Can be controlled.

The Young's modulus of the polypropylene foam molded body 100 is preferably 0.3 GPa or more, more preferably 0.5 GPa or more, further preferably 0.8 GPa or more, and particularly preferably 1.0 GPa or more.
By setting the Young's modulus to the above lower limit or more, the rigidity of the polypropylene foam molded body 100 can be further improved. As a result, deformation of the polypropylene foam molded body 100 with respect to external stress can be suppressed, or the polypropylene foam can be expanded. The scratch resistance, heat resistance, dimensional stability, and the like of the molded body 100 can be improved.
In addition, the Young's modulus of the polypropylene foam molded body 100 according to this embodiment is preferably 5 GPa or less, and more preferably 3 GPa or less.
By setting the Young's modulus to be equal to or less than the above upper limit value, the balance between the deformation resistance against external stress and the toughness of the polypropylene-based foamed molded product 100 can be improved.
Here, the Young's modulus of the polypropylene-based foam molded body 100 is an environment of 23 ° C. and 50% RH, and the shape of the test piece: strip shape, the width of the test piece: 10 mm, the distance between chucks: 50 mm, and the tensile speed: 20 mm. It is possible to measure one point for each of the MD direction and the TD direction under the condition of / min, and adopt an average value thereof.
The Young's modulus of the polypropylene-based foam molded body 100 is controlled within the above range by appropriately controlling, for example, the type and blending amount of the polypropylene-based resin, inorganic filler, and the like, and the expansion ratio of the polypropylene-based foam molded body 100, respectively. can do.

The arithmetic average roughness Ra of the surface of the polypropylene-based foamed molded product 100 is 2 from the viewpoint of further suppressing unevenness such as gloss unevenness and color unevenness on the surface and occurrence of vertical stripes (flow pattern) and improving the appearance. It is preferable that it is 5 μm or less.
The lower limit of the arithmetic average roughness Ra on the surface of the polypropylene-based foamed molded product 100 is not particularly limited, but is, for example, 0.1 μm or more.
The arithmetic average roughness Ra of the surface of the polypropylene-based foamed molded product 100 can be measured according to JIS-B0601-1994.

In order to realize the polypropylene-based foamed molded product 100 having the arithmetic average roughness Ra within the above range, the types and blending amounts of polypropylene-based resin and inorganic filler, the expansion ratio of the polypropylene-based foamed molded product 100, etc. It is important to use an inorganic filler having a low moisture content while appropriately selecting each.

The thickness of the polypropylene foam molded body 100 is not particularly limited, but is, for example, from 0.5 mm to 30 mm, preferably from 1.0 mm to 20 mm, more preferably from 1.5 mm to 12 mm, and still more preferably. It is 2.0 mm or more and 9.0 mm or less. When the thickness of the polypropylene-based foam molded body 100 is within this range, the balance of lightness, mechanical properties, recyclability, handleability, appearance, moldability, etc. is more excellent.

<Method for producing polypropylene-based foamed molded article>
The polypropylene-based foam molded body 100 can be obtained, for example, by foam-molding the polypropylene-based resin composition for foam molding according to the present embodiment into a predetermined shape. The molding apparatus and molding conditions are not particularly limited, and conventionally known molding apparatuses and foam molding conditions can be employed.

(Preparation method of polypropylene resin composition for foam molding)
In the polypropylene resin composition according to the present embodiment, each component is mixed or melted / kneaded by dry blending, tumbler mixer, Banbury mixer, single screw extruder, twin screw extruder, high speed twin screw extruder, hot roll, etc. Can be prepared.

(Molding method of polypropylene foam molding)
The polypropylene-based foam-molded body 100 can be obtained, for example, by foam-molding the above-described foam-molded polypropylene-based resin composition into a predetermined shape using an extrusion molding machine or an injection molding machine.
Examples of the foaming agent for molding the polypropylene-based foam molded body 100 include a chemical foaming agent and carbon dioxide gas.
Chemical foaming agents include sodium bicarbonate, ammonium bicarbonate, various carboxylates, sodium borohydride, azodicarboxamide, N, N-dinitrosopentamethylenetetramine, P, P-oxybis (benzenesulfonylhydrazide) Azobisisobutyronitrile, paratoluenesulfonyl hydrazide and the like.
Carbon dioxide gas can be supplied in a gaseous state, a liquid state, or a supercritical state.

It is preferable that the chemical foaming agent is blended with the polypropylene resin composition for foam molding and mixed uniformly before being introduced into the extruder.
When carbon dioxide gas is used as the foaming agent, it is preferable that the polypropylene resin composition for foam molding is kneaded and plasticized in the extruder and then directly pressed into the extruder.

The expansion ratio of the polypropylene resin composition for foam molding is not particularly limited, and can be appropriately determined in consideration of various physical properties of the polypropylene foam molded body 100 to be obtained.

<Uses of polypropylene foam moldings>
Polypropylene-based foam molded article 100 has an excellent appearance, and also has a good balance between lightness and mechanical properties, so it can be used as a substitute for wood boards, especially hard boards, medium-density fiber boards, and other high-rigidity wood boards. It can be used as a product.
More specifically, floor materials, wall materials, door materials, interior materials, exterior materials, window frames and other building materials; furniture; electrical and electronic components; partition materials; heat insulating materials; packing materials; automotive interior and exterior components; Sheets; toys; curing plates; miscellaneous goods; More specifically, customs boxes, logistics containers, sleepers, backing plates, floor plates, curing plates, spacers, billboards, shelf plates, backboards, bottom plates, insoles, ceiling materials, core materials, cushioning materials, sound absorbing materials, It can be used as a reinforcing plate, base plate, tatami floor, container, parts jig, transportation material, deck board, event / disaster material, concrete formwork, bed, musical instrument, and the like.

2. FIG. 2 is a cross-sectional view schematically showing an example of the structure of a polypropylene-based multilayer foamed molded product 200 according to an embodiment of the present invention.
The polypropylene-based multilayer foamed molded product 200 according to this embodiment is provided on one surface of the polypropylene-based foamed layer 100 constituted by the polypropylene-based foamed molded product 100 according to this embodiment, and the polypropylene-based foamed layer 100, and The first non-foamable resin layer 110 containing a thermoplastic resin and an inorganic filler, and the second non-foamable resin layer 120 provided on the other surface of the polypropylene foam layer 100 and containing a thermoplastic resin and an inorganic filler. And comprising.
Since the polypropylene-based multilayer foamed molded product 200 according to the present embodiment has an unfoamed inorganic filler-containing resin layer on the surface, the machine has bending characteristics, tensile properties, and the like compared to the polypropylene-based foamed molded product 100 according to the present embodiment. Characteristics can be improved.
The shape of the polypropylene-based multilayer foamed molded product 200 according to the present embodiment is not particularly limited, and is, for example, a sheet shape.

The thickness of the polypropylene-based multilayer foamed molded product 200 according to the present embodiment is not particularly limited, but is, for example, 0.5 mm to 30 mm, preferably 1.0 mm to 20 mm, and more preferably 1.5 mm to 12 mm. More preferably, it is 2.0 mm or more and 9.0 mm or less. When the thickness of the polypropylene-based multilayer foamed molded product 200 is within this range, the balance of lightness, mechanical properties, recyclability, handleability, appearance, moldability, etc. is more excellent.

Moreover, the thickness of the first non-foamable resin layer 110 and the second non-foamable resin layer 120 is not particularly limited, but is preferably 0.05 mm or more and 5 mm or less, and preferably 0.1 mm or more and 3 mm or less. More preferred.
Further, the ratio of the thickness of the first non-foamable resin layer 110 to the thickness of the polypropylene-based multilayer foamed molded article 200 is preferably 0.01 or more and 0.5 or less, more preferably 0.02 or more and 0.3 or less. Yes, more preferably 0.05 or more and 0.2 or less.
Further, the ratio of the thickness of the second non-foamable resin layer 120 to the thickness of the polypropylene-based multilayer foamed molded article 200 is preferably 0.01 or more and 0.5 or less, more preferably 0.02 or more and 0.3 or less. Yes, more preferably 0.05 or more and 0.2 or less.

Hereinafter, each component constituting the first non-foamable resin layer 110 and the second non-foamable resin layer 120 according to the present embodiment will be described.

<Thermoplastic resin>
The first non-foamable resin layer 110 and the second non-foamable resin layer 120 according to the present embodiment include a thermoplastic resin as an essential component.
As the thermoplastic resin according to the present embodiment, for example, a polyolefin resin can be used. Examples of polyolefin resins include homopolymers of α-olefins such as ethylene, propylene, butene-1,3-methylbutene-1,3-methylpentene-1,4-methylpentene-1, and copolymers thereof. Or the copolymer of these and other copolymerizable unsaturated monomers, etc. are mentioned.
More specifically, high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultrahigh molecular weight polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and other polyethylene-based polymers Examples thereof include resin; polypropylene resin; polybutene-1; poly-4-methylpentene-1. One type of polyolefin resin may be used, or two or more types may be used in combination. Among these, a polypropylene resin is preferable because it is excellent in lightness, rigidity, tensile strength, scratch resistance, low water absorption, and heat resistance.
As a polypropylene resin, the thing similar to the polypropylene resin used with the polypropylene foaming molding 100 which concerns on this embodiment mentioned above can be mentioned, for example.

<Inorganic filler>
The first non-foamable resin layer 110 and the second non-foamable resin layer 120 according to the present embodiment include an inorganic filler as an essential component.
Examples of the inorganic filler include talc, mica, clay, wollastonite, calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, kaolin, perlite, calcium sulfate, barium sulfate, potassium titanate, barium sulfate, calcium sulfite, Calcium silicate, silica, diatomaceous earth, alumina, titanium oxide, glass fiber, glass bead, glass balloon, milled fiber, montmorillonite, bentonite, guffite, aluminum powder, glass flake, carbon fiber, carbon flake, carbon balun, carbon Beads, carbon milled fiber, carbon black, graphite, carbon nanotube, ceramic fiber, molybdenum sulfide, aramid particles, aramid fiber, boron fiber, silicon carbide fiber, polyester Ren fibers, polypropylene fibers, polyester fibers, polyamide fibers, polyarylate fibers, various whiskers, wood flour, pulp, cellulose nanofibers, chaff, paper sludge, and the like. These can be used alone or in combination of two or more.

Among these, as the inorganic filler in the first non-foamable resin layer 110 and the second non-foamable resin layer 120, a polypropylene-based multilayer foam molding excellent in lightness, mechanical properties, recyclability, handleability and appearance. From the viewpoint of obtaining the body 200, it is preferable to include one or more selected from talc, mica and silica. Among these, talc and mica are preferable from the viewpoint of low cost, and talc is more preferable from the viewpoint of compatibility with polypropylene resin, foamability, moldability, colorability, low price, safety, and the like.

In addition, the inorganic filler may be used without treatment, in order to improve the interfacial adhesion with the thermoplastic resin and improve the dispersibility to the thermoplastic resin, a silane coupling agent, a titanium coupling agent, The surface may be treated with a surfactant or the like.

In addition, the water content of the inorganic filler according to this embodiment is preferably 0.10% by mass or less, more preferably 0.08% by mass or less, further preferably 0.07% by mass or less, based on the entire inorganic filler. More preferably, it is 0.06 mass% or less, Most preferably, it is 0.05 mass% or less. Although the minimum of the moisture content rate of the inorganic filler which concerns on this embodiment is not specifically limited, For example, it is 0.001 mass% or more with respect to the whole inorganic filler.
Here, the moisture content of the inorganic filler can be calculated, for example, by quantifying the moisture generated by heating the inorganic filler in a nitrogen stream and by the Karl Fischer coulometric titration method.
When an inorganic filler having a moisture content of not more than the above upper limit is used, occurrence of unevenness such as gloss unevenness, color unevenness and vertical streaks (flow pattern) on the surface is suppressed, and a polypropylene-based multilayer foam molded article having an excellent appearance. 200 can be obtained.
The inorganic filler having a moisture content of not more than the above upper limit value is, for example, obtained by heating the inorganic filler at 80 to 150 ° C. for about 0.5 to 48 hours using a dehumidifying dryer or a vacuum dryer. It can be obtained by removing moisture adsorbed inside.

The content of the inorganic filler in the first non-foamable resin layer 110 and the second non-foamable resin layer 120 is such that the thermoplastic resin contained in the first non-foamable resin layer 110 and the second non-foamable resin layer 120 and When the total amount of the inorganic filler is 100 parts by mass, each is preferably 5 parts by mass or more, more preferably 15 parts by mass or more, still more preferably 25 parts by mass or more, still more preferably 35 parts by mass or more, particularly preferably. Is 45 parts by mass or more.
Further, the content of the inorganic filler in the first non-foamable resin layer 110 and the second non-foamable resin layer 120 is the thermoplasticity contained in the first non-foamable resin layer 110 and the second non-foamable resin layer 120. When the total amount of the resin and the inorganic filler is 100 parts by mass, each is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, still more preferably 70 parts by mass or less, and particularly preferably 65 parts by mass or less. .

By setting the content of the inorganic filler in the first non-foamable resin layer 110 and the second non-foamable resin layer 120 to be equal to or higher than the lower limit, a machine such as a bending characteristic and a tensile characteristic of the polypropylene-based multilayer foamed molded body 200 is obtained. Characteristics, heat resistance, moisture resistance, and dimensional stability can be further improved.
Further, by setting the content of the inorganic filler in the first non-foamable resin layer 110 and the second non-foamable resin layer 120 to be equal to or lower than the above upper limit value, the light weight and high rigidity of the polypropylene-based multilayer foamed molded body 200 can be improved. The balance can be further improved, the moldability of the polypropylene-based multilayer foamed molded product 200 can be improved, and perforation and cutting of the polypropylene-based multilayer foamed molded product 200 can be suppressed. A polypropylene-based multilayer foamed molded product 200 can be realized.

In the polypropylene-based multilayer foamed molded article 200 according to this embodiment, it is preferable that the first non-foamable resin layer 110 and the second non-foamable resin layer 120 have the same composition and have the same thickness. By doing so, the linear expansion coefficients of the first non-foamable resin layer 110 and the second non-foamable resin layer 120 can be made to be the same value, so that the dimensions are due to deformation such as warpage due to thermal stress or moisture absorption. It is possible to obtain a polypropylene-based multilayer foamed molded product 200 that can suppress the change more effectively and that is further superior in mechanical properties such as bending properties and tensile properties and heat resistance.

<Other ingredients>
The first non-foamable resin layer 110 and the second non-foamable resin layer 120 according to the present embodiment include a heat stabilizer, an antioxidant, an ultraviolet absorber, a pigment, an antistatic agent, and copper damage prevention as necessary. Agent, flame retardant, neutralizing agent, foaming agent, plasticizer, nucleating agent, anti-bubble agent, crosslinking agent, weathering stabilizer, light stabilizer, anti-aging agent, fatty acid metal salt, softener, dispersant, colorant Additives such as lubricants, natural oils, synthetic oils and waxes may be blended.

<Method for producing polypropylene-based multilayer foamed molded article>
The polypropylene-based multilayer foamed molded product 200 according to the present embodiment is composed of, for example, an inorganic filler-containing thermoplastic resin composition containing an inorganic filler and a thermoplastic resin on both surfaces of the polypropylene-based foamed molded product 100 according to the present embodiment. It can be obtained by forming a resin layer.

(Preparation method of inorganic filler-containing thermoplastic resin composition)
Inorganic filler-containing thermoplastic resin composition according to the present embodiment, each component is mixed or melted by dry blend, tumbler mixer, Banbury mixer, single screw extruder, twin screw extruder, high speed twin screw extruder, hot roll, etc. -It can be prepared by kneading.

(Molding method of polypropylene multilayer foamed molded product)
The method for molding the polypropylene-based multilayer foamed molded product 200 according to the present embodiment can be performed by a known method using, for example, a multilayer extruder or a lamination molding machine. The polypropylene-based multilayer foamed molded product 200 forms, for example, a foam-molded polypropylene-based resin composition for forming the polypropylene-based foamed layer 100, and the first non-foamable resin layer 110 and the second non-foamable resin layer 120. The inorganic filler-containing thermoplastic resin composition to be obtained is supplied from the main extruder of the multilayer extruder and the hopper of the sub-extruder and is multilayer-extruded into a sheet form from the tip of the T die.
In addition, the polypropylene-based multilayer foamed molded body 200 is formed by separately molding the polypropylene-based foamed layer 100, the first non-foamable resin layer 110, and the second non-foamable resin layer 120, and laminating them to heat-mold them. Can also be obtained. In this case, for example, a polyolefin resin having a low melting point is formed between the polypropylene foam layer 100 and the first non-foamable resin layer 110 or between the polypropylene foam layer 100 and the second non-foamable resin layer 120. A thermal adhesive layer may be interposed. The polyolefin resin having such a low melting point is not particularly limited. For example, a polypropylene resin can be used, and a random copolymer of propylene and α-olefin is preferable.

<Uses of polypropylene-based multilayer foamed molded products>
Since the polypropylene-based multilayer foamed molded product 200 according to the present embodiment has an excellent performance balance between lightness and mechanical properties, it is an alternative to a wooden board, particularly a high-rigidity wooden board such as a hard board or a medium density fiber board. It can be used as a product.
More specifically, floor materials, wall materials, door materials, interior materials, exterior materials, window frames and other building materials; furniture; electrical and electronic components; partition materials; heat insulating materials; packing materials; automotive interior and exterior components; Sheet; Toy; Curing plate; Miscellaneous goods; Sporting goods; More specifically, customs boxes, logistics containers, sleepers, backing plates, floor plates, curing plates, spacers, billboards, shelf plates, backboards, bottom plates, insoles, ceiling materials, core materials, cushioning materials, sound absorbing materials, It can be used as a reinforcing plate, base plate, tatami floor, container, parts jig, transportation material, deck board, event / disaster material, concrete formwork, bed, musical instrument, and the like.

As described above, the embodiments of the present invention have been described with reference to the drawings. However, these are exemplifications of the present invention, and various configurations other than the above can be adopted.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples.

1. Measurement Method (1) Density of Polypropylene Foamed (Multilayer) Sheet A test piece was cut out from the polypropylene foamed (multilayer) sheet, and the test piece mass (g) was divided by the volume (cm ³ ) determined from the outer dimensions of the test piece. Asked.

(2) MFR of polypropylene resin
Based on ASTM D1238, the measurement was performed under the conditions of 230 ° C. and 2.16 kg load.

(3) Mz / Mw of polypropylene resin
A sample of 20 mg was dissolved in 20 ml of a mobile phase for GPC measurement at 145 ° C., and the obtained solution was filtered with a sintered filter having a pore size of 1.0 μm to obtain a measurement sample.
Next, using a gel permeation chromatograph (trade name “HLC-8321 GPC / HT type”) manufactured by Tosoh Corporation, the Z-average molecular weight (Mz) and the weight-average molecular weight (Mw) of the polypropylene resin were determined as follows. Measured and calculated Mz / Mw.
For the separation column, two trade names “TSKgel GMH6-HT” and two trade names “TSKgel GMH6-HTL” were used. The column sizes are 7.5 mm in inner diameter and 300 mm in length, the column temperature is 140 ° C., the mobile phase is o-dichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd.), and the antioxidant is BHT (Wako Pure Chemical Industries, Ltd.). (0.025% by weight).
The mobile phase was moved at a rate of 1.0 ml / min, the sample injection volume was 400 μl, and a differential refractometer was used as a detector. Standard polystyrene was manufactured by Tosoh Corporation. The molecular weight is a value converted into a polypropylene resin after universal calibration.

(4) Flexural modulus of polypropylene-based foamed (multilayer) sheet The flexural modulus of polypropylene-based foamed (multilayered) sheet was determined by referring to the flexural strength test described in JIS A5905 at an environment of 23 ° C. and 50% RH. Below, test piece thickness: 3 mm, test piece width: 50 mm, test piece length: 150 mm, span distance: 100 mm, bending speed: 50 mm / min. The average value was adopted.

(5) Young's modulus of the polypropylene-based foamed (multilayer) sheet The Young's modulus of the polypropylene-based foamed (multilayered) sheet is 23 ° C. and 50% RH environment, and the specimen shape: strip shape, specimen width: 10 mm The distance between chucks was 50 mm, the tensile speed was 20 mm / min, one point was measured for each of the MD direction and the TD direction, and the average value thereof was adopted.

(6) Arithmetic mean roughness Ra of the polypropylene-based foamed (multi-layer) sheet surface
The arithmetic average roughness Ra of the surface of the polypropylene-based foamed (multilayer) sheet is based on JIS-B0601-1994, and is a surface roughness measuring machine manufactured by Tokyo Seimitsu Co., Ltd. (model: E-MD-S189A, stylus tip shape (tip Radius: 2 μm, 60 ° cone, material: diamond)), evaluation length: 10 mm, measurement speed: 0.3 mm / second, cut-off value: 0.8 mm, measurement direction: parallel to the TD direction of the sheet surface Measured under various orientation conditions.

(7) Water content of inorganic filler The water content of the inorganic filler was calculated by the following method. First, moisture generated by heating the inorganic filler at 200 ° C. for 15 minutes in a nitrogen stream (100 ml / min) was quantified by Karl Fischer coulometric titration. Next, the moisture content of the inorganic filler was calculated from the obtained moisture content.

(8) Appearance Evaluation of Polypropylene Foamed (Multilayer) Sheet Visually observe the vertical streaks (flow pattern) and unevenness (gloss unevenness, color unevenness) on the surface of the polypropylene foam (multilayer) sheet. Evaluated by criteria.
○: There are no vertical stripes (flow pattern) and unevenness (gloss unevenness, color unevenness), and the appearance is good. ×: Vertical stripes (flow pattern) and unevenness (gloss unevenness, color unevenness) are slightly observed. XX: Vertical stripes (flow pattern) and unevenness (gloss unevenness, color unevenness) are conspicuous

(9) Evaluation of foamed cell form of polypropylene-based foamed (multilayer) sheet The microstructure of the foamed cell in the polypropylene-based foamed (multilayered) sheet was observed by X-ray CT scan, and the foamed cell form was evaluated according to the following criteria.
○: The foamed cells are relatively uniform and the cell shape is good. ×: The foamed cells are fused together, and bubbles (voids) are observed in the vicinity of the sheet surface.

2. Raw materials The raw materials used in Examples and Comparative Examples are shown below.
(1) Polypropylene resin PP1: Propylene homopolymer (VP103W manufactured by Prime Polymer, MFR: 3 g / 10 min, Mz / Mw value: 14)

(2) Masterbatch containing inorganic filler and polypropylene resin PP talc MB1 (manufactured by Mifuku Kogyo Co., Ltd., brand: MFP-TP20, composition: 20% by mass of propylene homopolymer and 80% by mass of talc, water content of talc Content: 0.15% by mass)
PP talc MB2 (PP talc MB1 was heat-treated at 105 ° C. for 18 hours to reduce the water content of talc to 0.05% by mass)
PP Mica MB (manufactured by Shiraishi Calcium Co., Ltd., Brand: HIFILLMER MAT-MPH80-60 (MFR: 3 g / 10 min, composition: containing 20% by mass of polypropylene composed of block copolymer and 80% by mass of mica, water content of mica) : 0.20% by mass) was heated at 120 ° C. for 18 hours, and the water content of mica was reduced to 0.075% by mass)
PP calcium carbonate MB (produced by Toyo Ink Co., Ltd., brand: PPM10245AL (containing 20% by mass of propylene homopolymer and 80% by mass of calcium carbonate) heated at 120 ° C. for 18 hours)
In addition, PP talc MB1 used the receipt state of the commercially available general purpose goods as it was.

3. Production of polypropylene-based foamed (multilayer) sheets [Examples 1 to 6 and Comparative Examples 1 to 8]
As a molding machine, a single screw extrusion molding machine (cylinder inner diameter D: 50 mm, full flight screw, L / D when screw effective length L is 32 mm, carbon dioxide supply position: 17.5 D from the screw supply part side), T Die (die width: 320 mm, lip opening: 0.5 mm), cooling roll (outside diameter 50 mm, steel with mirror finish hard chrome plating surface treatment, water-cooled), carbon dioxide supply device, cooling roll, and take-up machine The apparatus which consists of these was used.
First, each raw material was dry blended with the formulation shown in Table 1 (the unit in the table is parts by mass), the resulting mixture was put into a hopper, and further from the carbon dioxide supply device to the middle of the cylinder of the extruder (position) 17.5D) was injected with carbon dioxide at a pressure of 10 to 19 MPa. At this time, the injection amount of carbon dioxide gas was adjusted to 0.17 to 0.33 mass% with respect to the extrusion amount. Each component raw material is melted and kneaded under the conditions of a temperature of 173 to 193 ° C. in each part of the cylinder and a screw rotation speed of 30 to 55 rpm, and an extrusion rate of 10 to 19 kg / hour is obtained at a resin temperature of 186 to 215 ° C. in the cylinder head part. Extruded from a T-die. The extruded foam sheet is cooled with a cooling roll (roll water passage temperature 45 ° C.) and taken up using a take-up machine (take-up speed 0.4 to 0.7 m / min), and a polypropylene system having a sheet width of about 300 mm. Each foam sheet was obtained. Each evaluation was performed using the obtained polypropylene foam sheet. The obtained results are shown in Table 1, respectively.

[Comparative Example 9]
Each evaluation was performed using PALONIA (registered trademark) manufactured by Mitsui Chemicals, Inc. as a polypropylene-based foam sheet not containing an inorganic filler. The obtained results are shown in Table 1.

[Examples 7 to 10]
Each raw material was put into the hopper with the formulation shown in Table 2 (units in the table are parts by mass) into the extrusion molding machine used in Examples 1 to 6, cylinder temperature 205 to 215 ° C, die temperature 220 ° C, screw rotation Each raw material was melted and kneaded under the condition of several 22 to 28 rpm, and extruded from a T-die at a resin temperature of 229 to 231 ° C. of the cylinder head so that the extrusion rate was 8 to 13 kg / hour. The extruded foam sheet was taken up at a take-up speed of 1.0 m / min using a take-up machine, and polypropylene-based non-foamed sheets 1 to 4 having a sheet width of 290 to 300 mm were obtained.
Next, polypropylene-based foamed multilayer sheets having the layer structure shown in Table 3 were produced and evaluated. The obtained results are shown in Table 3, respectively.
Here, the polypropylene-based foamed multilayer sheet was laminated by inserting a thermal adhesive layer (a polypropylene film made of a random copolymer having a melting point of 139 ° C., thickness: 0.07 mm) between the layers. Furthermore, in order to provide surface smoothness and releasability from the surface plate to the upper and lower flat portions of the multilayer sheet in contact with the surface plate of the heating press device and the cooling press device, And a polyimide film having a mirror surface (arithmetic mean roughness Ra is 0.1 μm or less and thickness is 0.1 mm).
Using a hot press apparatus, the hot pressing was performed at a temperature of 150 ° C. and a pressure of 2.5 MPa for 8 minutes, and then the hot pressing was performed at a temperature of 150 ° C. and a pressure of 10 MPa for 1 minute. Then, the multilayer sheet containing the upper and lower polyimide films was inserted into a cooling press apparatus and cooled at a temperature of 25 ° C. and a pressure of 5 MPa. In addition, the metal frame of thickness 3mm used as a spacer was previously arrange | positioned inside the upper and lower polyimide films and the outer periphery of each multilayer sheet before the heat press. In this way, after heat bonding and cooling, polypropylene foamed multilayer sheets having a total thickness of about 2.8 to 3.0 mm were obtained.

As is clear from Tables 1 and 3, the polypropylene foamed sheets of Examples 1 to 6 and the polypropylene foamed multilayer sheets of Examples 7 to 10 using talc having a water content of 0.10% by mass or less are It was found that the appearance was excellent. In addition, the density and flexural modulus showed the same level as that of wood boards such as hard boards and medium density fiber boards, and it was found that the performance balance of light weight and mechanical properties was excellent. That is, it can be understood that the polypropylene foam molded body 100 according to the present embodiment is suitable as a substitute for the wooden board.
On the other hand, the polypropylene foam sheets of Comparative Examples 1 to 8 were all inferior in appearance. In addition, the polypropylene foam sheet of Comparative Example 9 had a poor performance balance between lightness and mechanical properties, and was not suitable as a substitute for a wooden board.

This application claims priority based on Japanese Patent Application No. 2016-213792 filed on Oct. 31, 2016, the entire disclosure of which is incorporated herein.

Claims

A polypropylene resin composition for foam molding containing a polypropylene resin and an inorganic filler,
The inorganic filler contains at least one selected from talc and silica,
A polypropylene resin composition for foam molding in which the moisture content of the inorganic filler is 0.10% by mass or less based on the whole inorganic filler.
In the polypropylene resin composition for foam molding according to claim 1,
A polypropylene resin composition for foam molding, wherein the inorganic filler contains talc.
In the polypropylene resin composition for foam molding according to claim 1 or 2,
Polypropylene for foam molding in which the content of the inorganic filler in the polypropylene resin composition is 5 parts by mass or more and 90 parts by mass or less when the total amount of the polypropylene resin and the inorganic filler is 100 parts by mass. Resin composition.
In the polypropylene resin composition for foam molding according to any one of claims 1 to 3,
When the total content of the polypropylene resin and the inorganic filler in the polypropylene resin composition for foam molding is 100% by mass with respect to 100% by mass as a whole, the polypropylene resin composition for foam molding is 100% by mass or more and 100%. A polypropylene-based resin composition for foam molding, having a mass% or less.
In the polypropylene resin composition for foam molding according to any one of claims 1 to 4,
In accordance with ASTM D1238, the polypropylene resin composition for foam molding, wherein the polypropylene resin has a melt flow rate of 0.5 g / 10 min or more and 20 g / 10 min or less measured under conditions of 230 ° C. and 2.16 kg load. .
In the polypropylene resin composition for foam molding according to any one of claims 1 to 5,
A polypropylene resin composition for foam molding, wherein the polypropylene resin has a Z average molecular weight (Mz) / weight average molecular weight (Mw) of 7 or more and 20 or less as measured by gel permeation chromatography (GPC).
A polypropylene-based foam-molded article comprising the foam-molded polypropylene-based resin composition according to any one of claims 1 to 6.
In the polypropylene-based foam molded article according to claim 7,
A polypropylene foam molded article having a density of the polypropylene foam molded article of 1.0 g / cm 3 or less.
In the polypropylene-based foam molded article according to claim 7 or 8,
A polypropylene foam molded article having a flexural modulus of 1.0 GPa or more of the polypropylene foam molded article measured in an environment of 23 ° C. and 50% RH.
In the polypropylene-based foamed molded article according to any one of claims 7 to 9,
The polypropylene-based foamed molded article measured under the conditions of 23 ° C. and 50% RH, and under the conditions of specimen shape: strip shape, specimen width: 10 mm, distance between chucks: 50 mm, and tensile speed: 20 mm / min. A polypropylene-based foamed molded article having a Young's modulus of 0.3 GPa or more.
In the polypropylene-based foam molded article according to any one of claims 7 to 10,
A polypropylene foam molded article having an arithmetic average roughness Ra of 2.5 μm or less on the surface of the polypropylene foam molded article, measured according to JIS-B0601-1994.
In the polypropylene-based foamed molded article according to any one of claims 7 to 11,
A polypropylene-based foamed molded product having a thickness of from 0.5 mm to 30 mm.
In the polypropylene-based foamed molded article according to any one of claims 7 to 12,
Polypropylene foam molded body used as an alternative to wood boards.
A polypropylene foam layer composed of the polypropylene foam molded article according to any one of claims 7 to 13, and
A first non-foaming resin layer provided on one surface of the polypropylene-based foam layer and containing a thermoplastic resin and an inorganic filler;
A second non-foaming resin layer provided on the other surface of the polypropylene-based foam layer and containing a thermoplastic resin and an inorganic filler;
A polypropylene-based multilayer foamed molded article.
In the polypropylene-based multilayer foamed molded article according to claim 14,
A polypropylene-based multilayer foamed molded article, wherein each of the first non-foamable resin layer and the second non-foamable resin layer has a thickness of 0.05 mm or more and 5 mm or less.
In the polypropylene-based multilayer foamed molded article according to claim 14 or 15,
The ratio of the thickness of the first non-foaming resin layer to the thickness of the entire polypropylene-based multilayer foamed molded article is 0.01 or more and 0.5 or less,
A polypropylene multilayer foamed molded article having a ratio of the thickness of the second non-foamable resin layer to the thickness of the entire polypropylene multilayer foamed molded article of 0.01 or more and 0.5 or less.
In the polypropylene-based multilayer foamed molded article according to any one of claims 14 to 16,
A polypropylene-based multilayer foamed molded article, wherein the inorganic filler in the first non-foamable resin layer and the second non-foamable resin layer contains one or more selected from talc, mica and silica, respectively.
In the polypropylene-based multilayer foamed molded article according to any one of claims 14 to 17,
The thermoplastic resin in which the content of the inorganic filler in the first non-foamable resin layer and the second non-foamable resin layer is included in the first non-foamable resin layer and the second non-foamable resin layer. A polypropylene-based multilayer foamed molded article that is 5 parts by mass or more and 90 parts by mass or less when the total amount of the resin and the inorganic filler is 100 parts by mass.
In the polypropylene-based multilayer foamed molded article according to any one of claims 14 to 18,
The first non-foaming resin layer and the second non-foaming resin layer have the same composition and have the same thickness, and are a polypropylene-based multilayer foamed molded article.
In the polypropylene-based multilayer foamed molded article according to any one of claims 14 to 19,
Polypropylene-based multilayer foamed molding used as an alternative to wood boards.
A production method for producing a polypropylene-based foamed molded article comprising a polypropylene-based resin and an inorganic filler,
The inorganic filler contains at least one selected from talc and silica,
Adjusting the moisture content of the inorganic filler to 0.10% by mass or less based on the whole inorganic filler by heating the inorganic filler;
A step of foam-molding a polypropylene resin composition containing the inorganic filler having a moisture content of 0.10% by mass or less and a polypropylene resin;
The manufacturing method of the polypropylene-type foaming molding containing this.