WO2020175635A1

WO2020175635A1 - Foamable resin composition and molded foam

Info

Publication number: WO2020175635A1
Application number: PCT/JP2020/008089
Authority: WO
Inventors: 泰正奥野; 智仁市来
Original assignee: バンドー化学株式会社
Priority date: 2019-02-28
Filing date: 2020-02-27
Publication date: 2020-09-03
Also published as: JP6810829B1; JPWO2020175635A1

Abstract

The present invention provides a foamable resin composition that obtains a molded foam having excellent foamability, thermal insulating property, and biodegradability and a molded foam obtained from the foamable resin composition. This foamable resin composition contains two or more biodegradable polymers and a layered silicate, wherein the two or more biodegradable polymers include a first and a second biodegradable polymer having at least a 2 g/10 min difference in melt mass flow rate; the first and second biodegradable polymers are contained in an amount of 10 to 80 wt% inclusive with respect to the entire foamable resin composition; the layered silicate is contained in an amount of 10 to 40 wt% inclusive relative to the entire foamable resin composition; the average particle size of the layered silicate is 0.05 to 100 μm inclusive; and the difference between the whiteness of the layered silicate and the whiteness of a non-foamed resin molding obtained from the foamable resin composition is 20% or less.

Description

\¥0 2020/175 635 1 卩 (: 17 2020 /008089 Clarification

Title of invention: Foaming resin composition and foamed molded product

Technical field

The present invention relates to a foaming resin composition and a foamed molded product.

Background technology

[0002] A foamed molded article is generally obtained by foaming a resin composition for foaming (hereinafter, also simply referred to as "resin composition"), which enables weight reduction, cost reduction, and heat insulation. be able to. Therefore, it is used in various applications such as food containers, daily necessities, and household electrical appliances. Furthermore, in recent years, foam-molded articles in consideration of the environment have attracted attention, and foam-molded articles using biodegradable resins have been investigated.

[0003] For example, Patent Document 1 discloses a foamed resin sheet formed from a composition containing a biodegradable resin as a main component and having sufficient mechanical strength, and containing starch as a main component and blending other materials. There is disclosed a foamed resin sheet and a foamed resin sheet molded article that can be bent and bag-formed by devising the ratio and devising the processing means. Further, in Patent Document 2, by mixing an equal amount or more of a polyester resin resin or foamed particles having insufficient rigidity with a resin or foamed particles made of a biodegradable resin having rigidity, the resin or foamed particles has higher rigidity than before. Polyester resin foamed particles, foamed molded products, and a method for producing the same are disclosed.

[0004] Further, in Patent Document 3, at least one polymer of a natural source and at least one

A mixture containing two diacid-diol type aliphatic monoaromatic polyesters. By mixing a specific amount of at least two diacid-diol type aliphatic monoaromatic polyesters, excellent mechanical properties, sufficient It is disclosed that a stable physical property over time can be obtained together with a high melting point, a sufficient crystallization rate, and an improved biodegradation property. It is also disclosed that the mixture is used for expandable beads, expanded products, and expanded sheets for use in food packaging. \¥0 2020/175 635 2 卩 (: 17 2020 /008089

Prior art documents

Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 2 0 1 0—2 5 4 8 5 9

Patent Document 2: Japanese Patent Laid-Open No. 20 1 4-0 4 0 5 0 6

Patent Document 3: Patent No. 5 7 2 7 4 9 7 Publication

Summary of the invention

Problems to be Solved by the Invention

[0006] Here, it is important for the foamed molded article that the cells formed by foaming (hereinafter, also referred to as "foamed particles") are evenly distributed inside, and the distribution of the foamed particles is uneven. In that case, defects on the surface of the foamed molded product, reduction in strength, and the like are caused. In order to uniformly foam in the foamed molded product, it is necessary that the resin composition before foaming is uniformly dispersed. However, when a biodegradable polymer is used because of environmental considerations, a foamed molded article is produced using a resin composition containing only one type of biodegradable polymer, which is considered to have good dispersibility in the resin composition. Then, there are problems that not only the foamed particles are non-uniformly distributed but also the proportion of the foamed particles in the foamed molded product is low. That is, there was a problem that the foamability was poor. Further, when two or more biodegradable polymers are used, it is difficult to uniformly disperse the resin composition, and there is room for further study in order to improve the dispersibility of the resin composition.

[0007] The present invention has been made in view of the above circumstances, and is a resin composition for foaming, which gives a foamed molded article having excellent foaming properties, heat insulating properties, and biodegradability, and the resin for foaming. The object is to provide a foamed molded product obtained from the composition.

Means for solving the problem

[0008] The present inventors have conducted a study on a method of using a biodegradable polymer to obtain a foamed molded article having a low environmental load and excellent molding processability, and found that the interfaces between incompatible polymers that do not dissolve each other Focusing on its high effect as a foam nuclei, two or more biodegradable polymers with a difference in melt mass flow rate of a specific value or more were separated. 〇 2020/175635 3 (: 171-1?2020/008089

It has been found that a foamed molded article having excellent foaming properties can be obtained by dispersing. It was also found that the addition of the layered silicate improves the shearing force during mixing, improves the dispersibility of two or more types of biodegradable polymers, and provides excellent foaming properties. Furthermore, they have found that the expanded particle size of the expanded particles can be made smaller by increasing the adhesion between the two or more biodegradable polymers and the layered silicate. As a result, they have found that the foamed molded product obtained has improved foaming properties and heat insulating properties, and has excellent biodegradability, and completed the present invention.

The foaming resin composition of the present invention is a foaming resin composition containing two or more types of biodegradable polymers and a layered silicate, wherein the two or more types of biodegradable polymers are melts. The first and second biodegradable polymers having a mass flow rate difference of 2.9 / 1001 or more are contained, and the content of the first and second biodegradable polymers is the entire foaming resin composition. On the other hand, both are 10% by weight or more and 80% by weight or less, and the content of the layered silicate is 10% by weight or more and 40% by weight or less with respect to the entire foaming resin composition, The average particle diameter of the layered silicate is 〇.

0 5 0 1 or more and 100 0 or less, the difference between the whiteness of the layered silicate and the whiteness of the non-foamed resin molded product obtained by the foaming resin composition is 20% or less. It is characterized by being.

[0010] The foaming resin composition further contains a filler, and the content of the filler is 0.01% by weight or more and 0.5% by weight or less with respect to the entire foaming resin composition. preferable.

[001 1] The specific gravity of the filler is preferably 0.5 or more and 4.0 or less.

The foamed molded article of the present invention is characterized by being formed by foaming the resin composition for foaming of the present invention.

[0013] It is preferable that the foam-formed product is one in which the foaming resin composition of the present invention and a supercritical fluid are mixed and foamed.

[0014] The foamed molded product is preferably obtained by injection molding the resin composition for foaming of the present invention.

Effect of the invention 〇 2020/175 635 4 卩 (：171? 2020 /008089

The foaming resin composition of the present invention is excellent in dispersibility, biodegradability and molding processability.

The foamed molded article of the present invention is formed by foaming the resin composition for foaming having the above-mentioned properties, and is excellent in foamability, heat insulation and biodegradability.

Brief description of the drawings

[Fig. 1] Fig. 1 is a schematic cross-sectional view of a foam molded article of the present invention.

FIG. 2 is a schematic diagram for explaining an example of a molding device used for producing a foam molded article.

MODE FOR CARRYING OUT THE INVENTION

[0018] Two or more types of biodegradable polymers have a difference in melt mass flow rate between the biodegradable polymers of 29/10.

It includes a first and a second biodegradable polymer having a density of at least n. Since the first and second biodegradable polymers are not compatible with each other, even if they are mixed, they do not dissolve each other and an interface is formed. This interface acts as a foam nucleus. However, the dispersion of two or more biodegradable polymers is insufficient because the shearing force at the time of mixing is low only by mixing two or more biodegradable polymers. Therefore, by further adding a layered silicate, the dispersibility of two or more types of biodegradable polymers can be improved, and the foaming nuclei can be highly dispersed in the foaming resin composition.

[0019] Two or more biodegradable polymers have a difference in melt mass flow rate (!\/! [¾). 〇 2020/175 635 5 卩 (：171? 2020 /008089

2 _9/1

It suffices to include the first and second biodegradable polymers having an I n or more.

Difference IV! In the first and second biodegradable polymer is preferably 1 0 0 ₉ / Rei_1丨n below. 1\/1 difference is 100

This is because if it exceeds n, the dispersibility of two or more biodegradable polymers may deteriorate. In addition,

Is a value measured in accordance with “3 [<7 210] and changing the temperature and load during measurement according to the polymer used.

[0020] The biodegradable polymer is not particularly limited, and a commonly used biodegradable polymer can be used. Examples of the biodegradable polymer include starch fatty acid ester, starch polyester, polylactic acid, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), polylactic acid/polycaprolactone copolymer, polyglycolic acid, and polyglycolic acid. Lactic acid/polyether copolymer, butanediol/long-chain dicarboxylic acid copolymer, polyptyrene adipite/terephthalate, polytetramethylene adipate·coterephthalate, polyethylene terephthalate copolymer (1, 4-6 0, succinic acid, adibe acid, milk acid) Cobolimer, polyethylene sebacate, polypropylene succinate, polypropylene succinate adipate, polyptyrene adipate terephthalate, polyvinyl alcohol, polyhydroxybutyric acid, poly Examples thereof include caprolactone, poly (caprolactone/butylene succinate), and poly (ptyrene succine-carbohydrate). The first and second biodegradable polymers are biodegradable polymers selected from these groups and having a melt mass flow rate difference of 2 9/100 1 n or more. The two or more biodegradable polymers may include different biodegradable polymers in addition to the first and second biodegradable polymers. However, the types of biodegradable polymers, including the first and second biodegradable polymers, are preferably 4 or less. This is because the handleability of the resin composition becomes complicated.

[0021] Further, as the biodegradable polymer used in the resin composition of the present invention, polylactic acid, polypropylene succinate, polypropylene adipate terephthalate and 〇 2020/175 635 6 卩 (：171? 2020 /008089

At least one selected from the group consisting of polycaprolactone can be preferably used, and at least one selected from polylactic acid and polypropylene succinate can be more preferably used. In particular, when polylactic acid is used to form a two-component resin composition, the molding processability is good, and therefore it can be used particularly preferably.

[0022] The polylactic acid is not particularly limited, and! _ _ Lactic acid or a homopolymer of lactic acid,! _ _ Lactic acid and a copolymer of lactic acid, or a mixture of these homopolymers and/or copolymers. Polylactic acid with different crystallinity obtained depending on the ratio of enantiomers of lactic acid, the method of copolymerization of enantiomers (random, block, graft, etc.) or the method of adding a crystal nucleating agent is used. You may choose.

[0023] The above-mentioned polypropylene succinate is not particularly limited, and succinic acid (!!

1 ^~ 1 ₂ ○ 1 ^~ 1 ₂ ○ ○ ○ 1 ^~ 1) and 1,4-butanediol (1 ^~ 1 ○ (○ 1 ^~ 1 ₂ ) ₄ ○ 1 ^~ 1) as raw materials synthesized by dehydration polycondensation The commercially available products (for example, Mimi Tatsumi 3 (manufactured by Mitsubishi Chemical Corporation), etc.) can be used.

[0024] The content of each of the first and second biodegradable polymers used in the resin composition of the present invention is 10% by weight or more and 80% by weight or less with respect to the entire resin composition. ..

When the content of the resin composition of either one of the first and second biodegradable polymers is less than 10% by weight or more than 80% by weight, the resin composition for foaming is foamed. The foamability of the foamed molded product formed by molding becomes insufficient. The content of the first biodegradable polymer is preferably 30% by weight or more and 70% by weight or less, more preferably 40% by weight or more and 60% by weight or less. The content of the second biodegradable polymer is preferably 10% by weight or more and 45% by weight or less, more preferably 10% by weight or more and 36% by weight or less.

[0025] The types and contents of the first and second biodegradable polymers are appropriately set within the above range from the viewpoint of improving the fluidity of the resin composition and the moldability. be able to.

[0026] The melt viscosity (2 2 0 ^° 〇 biodegradable polymers used in the resin composition of the present invention, 1 5 0 3 3 or more, preferably 4 0 0 3 3 below. The above 〇 2020/175 635 7 卩 (：171? 2020 /008089

A more preferred lower limit of the melt viscosity of the biodegradable polymers is a 2 0 0 ₃ 3, and a more preferred upper limit is 3 0 0 3 3. The melt viscosity can be measured, for example, using a flow tester 0-500, manufactured by Shimadzu Corp. Specifically, the resin to be measured is heated to a predetermined temperature to fluidize it, and then it is passed through a cavity die (inner diameter 0 1, length 10 ), and a cylinder with a biston with a predetermined surface pressure of 11 \/1 3 is used. Viscosity characteristics can be evaluated by the amount of viston movement and the time it takes.

[0027] is 1 \ / 1 [difference ¾ 2 ₉ / Rei_1丨n or as a method of mixing the first and second biodegradable polymers together, a method of forming a chemical bond between the two components Alternatively, a method of forming a crosslinked structure between the same polymer or the like can be used.

For example, when polylactic acid is used as a biodegradable polymer to obtain a foamed molded article, reactive extrusion (reactive extrusion) is performed in which kneading is performed while synthesizing polylactic acid using a synthetic catalyst such as a metal complex or a radical generator. Processing) may be used. INDUSTRIAL APPLICABILITY According to the present invention, an interface formed between two or more specific biodegradable polymers acts as a foam nucleus, and unlike reactive extrusion in which kneading is performed while synthesizing polylactic acid, a synthetic catalyst is contained in a resin composition. It is not necessary to add a radical generator or the like.

[0028] As an example of reactive extrusion of polylactic acid, for example, tin 2-ethylhexanoate is used as a synthesis catalyst, and an antioxidant (eg, Irganox 1101 manufactured by Ciba Specialty Chemicals) is added. do it! --- Method of reacting lactide with £ _ caprolacton; Method of reacting polylactic acid with polyethylene glycol using a radical generator such as dicumyl peroxide; Method of reacting polylactic acid with polycarbonate using a radical generator Examples include a method of graft-polymerizing polyptyrene adduct monoterephthalate (Mitsuhaccho), polycaprolactone (○!_), polyptyrene succinate (M3), polyptyrene succinate adibe (Mitsuhachi), and the like.

[0029] The layered silicate is not particularly limited, and examples thereof include pyrophyllite, talc, kaolin (kaolinite), montmorillonite, fisheye stone, margara. 〇 2020/175 635 8 卩 (：171? 2020 /008089

It, plenite, mica (mica) and the like can be mentioned, and particularly, talc, force Olin, montmorillonite or mica (mica) is preferably used. The above layered silicates may be used alone or in combination of two or more. In addition, it is preferable to use talc and/or mica as the layered silicate.

[0030] The content of the layered silicate is 10% by weight or more based on the entire resin composition,

It is 0% by weight or less. When two or more layered silicates are used in combination, the total content should be within the above range.

If the content of the above layered silicate with respect to the entire resin composition is less than 10% by weight, the effect of improving the shearing force at the time of mixing cannot be sufficiently obtained, so that two or more biodegradable polymers should be used. It cannot be sufficiently dispersed, and if it exceeds 40% by weight, the moldability of the resin composition for foaming deteriorates.

The preferable lower limit of the content of the layer silicate with respect to the entire resin composition is 15% by weight, and the preferable upper limit is 35% by weight.

[0031] The average particle size of the layered silicate is 0.05 or more and 100 or less. If the average particle size of the layered silicate is less than 0.05, two or more types of biodegradation are obtained. This is because the effect of improving the shearing force at the time of mixing the water-soluble polymer cannot be sufficiently obtained, and when the average particle size exceeds 100, the strength of the foam-molded article is significantly reduced. The preferable lower limit of the average particle diameter of the layered silicate is 0.5, and the more preferable lower limit is 1. The preferred upper limit of the average particle diameter of the layered silicate is 80, and the more preferred upper limit thereof is 30.

When two or more of the above layered silicates are used in combination, the average particle size of the layered silicate is the average particle size measured in the state in which the two or more layered silicates used are mixed. means.

[0032] The average particle size of the layered silicate is 50% average particle size, and is measured using, for example, a Shimadzu laser diffraction particle size distribution analyzer (trade name: 3 1_ 0 _ 200 0 0). You 〇 2020/175 635 9 卩 (：171? 2020 /008089

You can

[0033] Further, the difference between the whiteness of the layered silicate and the whiteness of the non-foamed molded product obtained from the resin composition is 20% or less. The addition of the layered silicate improves the dispersibility of two or more biodegradable polymers, but if the adhesion between the layered silicate and the two or more biodegradable polymers is poor, foaming The expanded particles in the expanded molded article formed by expanding the resin composition are enlarged. That is, since the foamed particle diameter of the foamed particles inside the foamed molded article becomes large, it becomes difficult to produce a foamed molded article having dense foamed particles in which a large number of foamed particles having a small particle diameter are generated.

[0034] Here, when the difference between the whiteness of the layered silicate and the whiteness of the foam-free resin molding obtained from the resin composition is 20% or less, the layered silicate is It is considered that the adhesion between the layered silicate and the two or more types of biodegradable polymers in the resin composition is good by mixing the above and two or more types of biodegradable polymers. The difference in whiteness can be adjusted by changing properties such as polarity from a commercially available layered silicate.

The difference between the whiteness of the layered silicate and the whiteness of the non-foamed molded product obtained from the resin composition is preferably 10% or less, more preferably 5% or less.

[0035] The whiteness of the layered silicate and the whiteness of the non-foamed molded product should be measured using a spectral color difference meter 3600 made by Nippon Denshoku Industries Co., Ltd. You can

Further, the non-foamed molded article can be obtained, for example, by mixing the two types of biodegradable polymers and the layered silicate, melt-kneading, and then transferring to a mold and cooling. ,

Above, 6

It is formed into a flat plate having the following thickness. Therefore, when measuring the whiteness,

Above, 6

It is a flat non-foamed molded product having a thickness of 0! or less.

When measuring the whiteness of the layered silicate, the layered silicate is rolled to form a sheet, and the whiteness is measured. In addition, there are two or more layered silicates. 〇 2020/175 635 10 卩 (：171? 2020 /008089

When used together, measure the whiteness of the mixture of two or more layered silicates used.

[0036] The foaming resin composition of the present invention preferably further contains a filler, and the content of the filler is from 0.01% by weight or more to 0.5% by weight or less based on the entire resin composition. Preferably.

When the content of the above filler in the whole resin composition is less than 0.01% by weight, the addition of the filler will improve the dispersibility of the two biodegradable polymers and the foamability of the resulting foamed molded article. The effect of improvement is not sufficiently obtained, and if it exceeds 0.5% by weight, the foamability of the obtained foamed molded product may be deteriorated.

The preferable upper limit of the content of the filler with respect to the entire resin composition is 0.3% by weight.

[0037] The filler has a density of 0.2% with respect to the density of the layered silicate.

Those having different densities are preferable, and other components contained in the resin composition for foaming, that is, two or more kinds of biodegradable polymers, and a compound different from the layered silicate are composed of inorganic materials. The inorganic filler may be an organic filler composed of an organic material, or a mixture thereof. And the filler, the difference in density between the layered silicate 〇. More preferably 2 5 9 / Rei_rei_1 ³ or more, 〇.

Yes. The density of the filler may be higher or lower than the density of the layered silicic acid. The density of the filler and the density of the layered silicate can be measured by a pycnometer method.

[0038] Examples of the inorganic filler include metal oxides such as magnesium oxide and calcium oxide, graphite, carbon black, molybdenum disulfide, tungsten disulfide, calcium carbonate, silica, silica gel, zeolite, boron nitride. , And a filler containing alumina or the like.

[0039] Examples of the organic filler include, for example, fluororesins such as polytetrafluoroethylene (Tomo), ultra high molecular weight polyethylene, electron beam cross-linking polyethylene, aromatic polyamides, aliphatic polyamides, silicon carbide, acrylic resins. , Hue 〇 2020/175 635 1 1 卩 (: 171? 2020 /008089

Examples include fillers containing a knoll resin and a melamine resin. The above ultrahigh molecular weight polyethylene and electron beam crosslinkable polyethylene have extremely low fluidity even when they are in a molten state by heating above the melting point, and therefore cannot be numerically evaluated by the melt mass flow rate (IV! [¾] measurement.

[0040] The filler preferably has a specific gravity of 0.5 or more and 4.0 or less. This is because at the time of blending, high dispersibility is easily obtained due to collision with polymer and collision between fillers.

The specific gravity of the filler is the ratio of the density of the filler to the density of water as a reference substance, and can be calculated using the density measured by the pycnometer method.

[0041] The method for producing the foaming resin composition of the present invention is not particularly limited, but a known method can be used. For example, a method of melting and kneading a mixture of each component with various single-screw or multi-screw extruders can be mentioned. Each component may be kneaded at once, or any component may be kneaded and then the remaining components may be added and kneaded.

[0042] A foamed molded article is obtained by foaming and molding the above-mentioned foaming resin composition. In the foaming resin composition, a specific layered silicate is added to improve the dispersibility of two or more types of biodegradable polymers, and further, two or more types of biodegradable polymers and layered silicates are added. Since the adhesiveness is improved, fine bubbles can be uniformly present inside the foamed molded product obtained by foaming the same. Therefore, the foamed molded product is excellent in heat insulating property, strength and lightness in addition to biodegradability.

[0043] When a random pattern, color, characters or the like is applied to the surface of the foam molded article, a pigment filler, a color masterbatch or the like may be added to the foam resin composition.

[0044] It is preferable that the foamed molded product is obtained by mixing and foaming the foaming resin composition and a supercritical fluid. The foaming resin composition has a fine interface formed by highly dispersing two or more types of biodegradable polymers that are insoluble in each other. Therefore, in foaming using a supercritical fluid, the above interface becomes the foaming starting point. 〇 2020/175 635 12 卩 (：171? 2020 /008089

Therefore, fine bubbles can be uniformly present inside the foamed molded product, and the properties such as heat insulating property, strength, and lightness can be sufficiently exhibited. Examples of the supercritical fluid include carbon dioxide, nitrogen, argon, and an inert gas such as helium. Of these, a supercritical fluid of carbon dioxide or nitrogen is preferable, and a supercritical fluid of nitrogen is more preferable.

[0045] In the method for producing a foamed molded article using the above-mentioned supercritical fluid, first, a supercritical fluid is injected into a melted resin composition for foaming under high pressure and stirred to obtain a resin composition for foaming. A single phase melt with a supercritical fluid is obtained. Next, by reducing the pressure, the supercritical fluid in the single-phase melt will undergo a phase transition to gas, and bubbles will be generated. When a large number of foaming starting points are present uniformly, a foamed molded product containing a large number of fine expanded particles is obtained. As a result, the foaming resin composition is foamed to obtain a foamed molded product having fine foamed particles.

[0046] The foamed molded product is preferably obtained by injection molding of the foaming resin composition. In particular, the foamed molded product is preferably obtained by a method of performing injection molding while impregnating the foaming resin composition with a supercritical fluid (hereinafter, also referred to as supercritical injection molding). The foaming resin composition can be processed into a precise shape and various shapes by supercritical injection molding. Among them, in supercritical injection molding, after filling the above-mentioned foaming resin composition in a molten state in the cavity part (cavity) of the mold, by moving a part of the mold before cooling and solidification proceed, It is preferable to foam by a method of forcibly expanding and causing a rapid pressure decrease (hereinafter, core back method). By using the core back method, the foaming amount can be greatly increased.

[0047] Fig. 1 is a schematic cross-sectional view of a foam molded article of the present invention. The foamed resin composition of the present invention and a supercritical fluid are mixed, and then injection-molded to foam, whereby the foamed molded article 10 shown in FIG. 1 is obtained. The foamed molded product 10 has skin layers (outer skin layers) 11 on both sides of the foamed layer 12. The foam layer 12 is a region having uniform foam particles, and the skin layer 11 is formed by forming foam particles on the surface side of the foam molded article. 〇 2020/175 635 13 卩 (：171? 2020 /008089

It refers to the area that does not exist. Since the surface of the foamed molded article 10 is the skin layer 11, the strength of the foamed molded article 10 can be increased and the surface can be made smooth. Further, since the central portion is the foam layer 12, not only can the weight be reduced, but also heat cannot be transmitted easily, so that the heat insulation of the foam molded body 10 is improved.

[0048] The thickness of the foamed molded product is from 0.2 to 3.0.

Is preferred. The thickness of the foamed molded product is 0.2.

If it is less than 3.0, foaming may not occur, and if it exceeds 3.0, unevenness may occur on the surface and the appearance may be impaired. According to the foaming resin composition of the present invention, since the foaming property and the moldability are superior to those of the conventional foaming resin composition, practically sufficient heat insulating property and strength are secured even if the foaming resin composition is thinner than the conventional one. It is possible to produce a foamed molded product.

[0049] The above-mentioned foamed layer preferably has 100 or more foamed particles in the range of 11 of the foamed layer when observing the cross section of the foamed molded article, and 100 foamed particles selected arbitrarily. The average particle size of the particles is preferably 100 or less. Foamed particles can be measured with a scanning electron microscope (3M IV!), for example, 3-4800 manufactured by Hitachi High-Technologies Co., Ltd. can be used.

Mixing the foaming resin composition with the supercritical fluid, and foaming and molding the foaming resin composition can be performed, for example, by using an injection molding machine and a supercritical fluid generator. Can be performed using a device connected to the. An example of a device in which an injection molding machine and a super-realistic fluid generator are connected is, for example,

I 丨 injection molding machine (1 \ / 1 ri 〇 6 丨 I is a "6 X 6 丨. 〇〇 _ 1 _ 1 registered trademark) and the like.

[0051] Fig. 2 is a schematic diagram for explaining an example of a molding apparatus used for producing a foam molded article. As shown in Fig. 2, the molding device 20 is equipped with a hopper 21 for feeding material, a heating cylinder 2 2 equipped with a screw 23, and an injection molding machine equipped with a nozzle 24 via an injection controller 27. The cylinder 25 and the supercritical fluid generator 26 are connected.

[0052] As a specific example of the production method, first, two or more biodegradable polymers (for example, poly 〇 2020/175 635 14 卩 (：171? 2020 /008089

Lactic acid and polyethylene succinate) and layered silicate are melt-mixed by a twin-screw extruder having a set temperature of 200 ^° C. or higher to produce a pellet-shaped resin composition for foaming. Next, the pellet-shaped foaming resin composition obtained above was put into a hopper 21 and the screen 23 was rotated according to a general injection molding procedure to prepare the pellet-shaped foaming resin composition. Dissolve and weigh. During melting and weighing of the pellet-shaped foaming resin composition, the supercritical fluid is introduced into the cylinder 2 2 through the injection controller 27 connected to the cylinder 25 and the supercritical fluid generator 26. Is injected and the screw 23 is rotated to mix and impregnate the melt of the foaming resin composition with the supercritical fluid, thereby forming a single-phase melt. The measured single-phase melt is conveyed to the nozzle 24 side by the screw 23 and injected into the die 28. Due to the pressure loss in the mold 28, the supercritical fluid undergoes a phase transition to a gas at the time when the critical pressure is reached and bubbles are generated. Further, there is also a method of increasing the foaming amount by accelerating the pressure decrease in the mold 28 by expanding the cavity when the single-phase melt is injected into the mold 28.

Example

[0053] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0054] (Ingredients)

The compounding raw materials used for preparing the resin compositions for foaming in the following Examples and Comparative Examples are shown in Table 1 below.

[0055]

[¾ji

〇 2020/175 635 16 卩 (: 171? 2020 /008089

[0056] (Example 1)

64.5% by weight of biodegradable polymer, poly(ethylene succinate) (3) and 10.5% by weight of polylactic acid (!_8), and 25% by weight of layered silicate, talc (25%). The mixture was dry-blended and kneaded with a twin-screw extruder (manufactured by Nippon Steel Works, Ltd., Dingumi 30) at a temperature setting of 220 ^° to obtain a pellet-shaped foaming resin composition.

[0057] Next, the obtained pellet-shaped resin composition for foaming was put into a supercritical injection molding machine (manufactured by Toshiba Machine Co., Ltd.), and the resin composition for foaming was dissolved at a cylinder temperature of 210 ^°. While being impregnated with a supercritical fluid, a foamed molded body was obtained by a core back method using supercritical injection molding. The supercritical fluid using supercritical fluids nitrogen loading 〇. 1 by weight%, and the filling pressure 1 3 0 IV! _3. Molding conditions are Screwil back pressure 15 IV! ₃ , injection speed

The mold temperature was set to 50°. Vertical 80, Horizontal 80, Thickness 2

Was molded into a plate shape to obtain a foamed molded body. The filling amount of supercritical fluid (unit:% by weight) can be calculated by the following formula (1).

[(Flow rate of supercritical fluid X Inflow time of supercritical fluid X Conversion coefficient 27.8) ÷ Weight of resin composition for foaming] X 1 〇〇 (1)

[0058] The obtained foamed molded article was a foamed molded article having skin layers on both sides of the foamed layer, as shown in Fig. 1.

[0059] (Examples 2 to 15)

The foaming resin compositions and foam moldings according to Examples 2 to 15 were performed in the same manner as in Example 1 except that the blending raw materials and their blending amounts were changed to the blending raw materials and blending amounts shown in Table 2 below. The body was made. Table 2 shows the content of each compounding raw material in the entire foaming resin composition, the difference in IV! in the polymers used, the average particle diameter of the layered silicate, and the whiteness of the layered silicate. The difference from the whiteness of the non-foamed molded product obtained from the resin composition was described.

[0060] (Comparative Examples 1 to 12)

The foaming resin compositions and the foaming resin compositions according to Comparative Examples 1 to 12 were prepared in the same manner as in Example 1 except that the blending raw materials and their blending amounts were changed to the blending raw materials and blending amounts shown in Table 3 below. 〇 2020/175 635 17 卩(：171? 2020/008089

And a foamed molded body were produced. Table 3 shows the content of each compounded raw material in the entire foaming resin composition, the difference in IV! in the polymers used, the average particle diameter of the layered silicate, and the whiteness of the layered silicate. The difference from the whiteness of the non-foamed molded product obtained from the resin composition was described.

The average particle diameter of the layered silicate and the granular silicate used in the examples and comparative examples was measured by the following procedure. The whiteness of the layered silicate and the whiteness of the non-foamed molded product obtained from the resin composition were measured by the following methods.

(Measurement of average particle diameter of layered silicate and granular silicate)

The average particle size of the layered silicate and granular silicate is 50% average particle size, measured using a Shimadzu laser diffraction particle size distribution analyzer (trade name: 3 !_ 0 _ 200 0 0) did.

(Measurement of Whiteness of Foam-Free Molded Article Obtained from Layered Silicate and Resin Composition) The surface of the non-foamed molded article obtained from the silicate powder and the resin composition was treated by Nippon Denshoku Industries Co., Ltd. The measurement was carried out using a spectrophotometer manufactured by Co., Ltd. 3 days 600. As the non-foamed molded product, a plate-shaped non-foamed molded product having a thickness of 301 0 1 or more was cut into 100 1 0 1 111 X 100!

[0064]

〔〕〔卍⁰⁰⁶ _5-

〇 2020/175 635 20 卩 (：171? 2020 /008089

(Evaluation of Foaming Resin Composition and Foamed Molded Product)

The foaming resin compositions prepared in Examples and Comparative Examples were evaluated for moldability, foamability, heat insulation and biodegradability. The results are shown in Table 4 below.

(1) Moldability of foaming resin composition

The moldability of the resin composition for foaming was evaluated by the fluidity during injection molding and the cooling and solidifying property after injection molding. The case where the fluidity during injection molding and the cooling and solidifying property after injection molding were good was indicated by ◯, and the case where either the fluidity during injection molding or the cooling and solidifying property after injection molding was poor was indicated by X.

For evaluation of fluidity during injection molding, injection pressure of resin composition for foaming

Below, 20 injections were performed, and it was judged that the liquidity was good when unfilled was not confirmed, and the liquidity was judged to be poor when unfilled was confirmed at least once. After injection molding, the cooling and solidifying property was evaluated by cooling the mold for 1 minute with a mold set ^at 50 ^° and visually confirming the deformation when the foamed molded product was taken out from the mold, and if no deformation was confirmed. It was judged that the cooling and solidifying property was good, and when the deformation was confirmed, the cooling and solidifying property was bad. For the evaluation of fluidity and the evaluation of solidification by cooling, a plate-shaped mold having a length of 80, a width of 8001111, and a thickness of 201101 was used.

[0068] (2) Foaming property

The cross section of the foamed molded article was observed by 3 1//1 (manufactured by Hitachi High-Technologies Corporation, 3-4800) to confirm the state of the foamed particles in the foamed layer.

The foamability was evaluated by observing the foamed molded article from the cross-section, and there were 100 or more foamed particles in the range of 10! and 10! in the foam layer, and 10 were selected arbitrarily. ○ When the average particle size of the foamed particles is less than 60, it is marked as ◎, when it is more than 60 and less than 80, it is marked as ◯, and when it is more than 800! , When the average particle size of the expanded particles is larger than 100

[0069] (3) Thermal insulation

After spraying a black-body spray (Taskojapan Co., Ltd., "Cho! ^~ 1 I _ 1 Mimi") on a plate-shaped foamed molded product (150 1 500), it was included in the black-body spray. 〇 2020/175 635 21 卩 (：171? 2020 /008089

The solvent to be immersed was dried indoors for 12 hours to 24 hours to prepare a black colored plate-like sample for measurement. Then, place the measurement sample on the hot plate set at 90 ^°, and after 3 minutes, measure the surface temperature of the measurement sample on the side opposite to the hot plate contact surface from the center of the measurement sample.

The infrared radiation thermometer adjusted to an emissivity of 0.94 (“Dai 3-200” manufactured by Japan Avionics Co., Ltd.) was used for the measurement.

Where the measured surface temperature was 60 ° 〇 below and ◎, a case was 60 ° 6 5 ^° 0 higher than 〇 hereinafter as 〇, the case was higher than 65 ^° 0 was X.

[0070] (4) Biodegradability

The biodegradability of the foamed molded product was evaluated by a method according to 1 301 4855 ("1 3 X6953). A 10×10 0 plate-shaped foam molded body was buried in microbially active soil for 180 days, and the appearance was observed and the mass was measured. The culture temperature was set to 58 ^° 〇 ± 2 ^° 〇. If the mass of the plate-shaped foam molded article after the evaluation is 90% or less of the mass of the plate-shaped foam molded article before the evaluation, the evaluation result is ◯, and 90% of the mass of the plate-shaped foam molded article before the evaluation is The evaluation result in the case of exceeding is defined as X.

[0071]

〇 2020/175 635 22 卩 (：171? 2020 /008089

[Table 4]

Explanation of symbols

[0072] 10 Foam molded article

1 1 Skin layer (outer skin layer)

1 2 foam layer

20 Molding equipment

2 1 hopper

22 cylinders

23 Skrill

24 nozzles

25 cylinders \¥02020/175635 23 卩 (: 17 2020 /008089

26 Supercritical fluid generator

27 Injection controller

28 Mold

Claims

\¥0 2020/175 635 24 (: 17 2020/008089 Claims

[Claim 1] A foaming resin composition comprising two or more biodegradable polymers and a layered silicate,

The two or more biodegradable polymers, the difference is 2 _9/1 0 melt mass flow rate

Including the first and second biodegradable polymer is I n or more, the content of the first and second biodegradable polymer are both 10 wt% or more with respect to the entire foaming resin composition, 8 0% by weight or less, the content of the layered silicate is 10% by weight or more and 40% by weight or less with respect to the entire foaming resin composition,

The average particle size of the layered silicate is 0.05 or more, 100 or less,

A foaming resin composition, wherein the difference between the whiteness of the layered silicate and the whiteness of a non-foamed resin molding obtained from the foaming resin composition is 20% or less.

[Claim 2] A filler is further included, and the content of the filler is not less than 0.01% by weight and not more than 0.5% by weight with respect to the entire foaming resin composition. The resin composition for foaming according to.

[Claim 3] The foaming resin composition according to claim 2, wherein the filler has a specific gravity of 0.5 or more and 4.0 or less.

[Claim 4] A foam-molded article obtained by foaming and molding the resin composition for foaming according to any one of claims 1 to 3.

[Claim 5] The foam according to claim 4, wherein the foaming resin composition according to any one of claims 1 to 3 is foamed by mixing with a supercritical fluid. Molded body.

[Claim 6] The foam-molded article according to claim 4 or 5, which is obtained by injection-molding the foaming resin composition according to any one of claims 1 to 3.