JP4821113B2 - Foam and production method thereof - Google Patents

Description

  The present invention is a foam comprising a resin composition comprising a polylactic acid resin, a naturally-derived organic filler, and an ester plasticizer having a specific structure, and has excellent heat resistance, light weight and bleed-out resistance. The present invention relates to an excellent foam and a method for producing the same.

  The polylactic acid resin has a high melting point and can be melt-molded. Therefore, it is expected to be a practically excellent resin derived from plant resources.

  However, since polylactic acid resin alone has insufficient heat resistance and mechanical strength, studies have been made to add a filler in order to improve the problem. As the filler used, many attempts have been made to add naturally-derived organic fillers such as wood powder, paper powder and kenaf from the viewpoint of protecting the global environment.

  However, when they are used as products such as molded products, they are extremely weak and vulnerable to impacts, so attempts have been made to make foams for the purpose of improving the problem and reducing the weight. Is also disclosed in Patent Document 1.

  Patent Document 1 proposes a foam made of polylactic acid and plant powder and a method for producing the same, but the specifically obtained foam has a large foaming ratio and is reduced in weight. However, the heat resistance was insufficient.

  On the other hand, a method of adding a plasticizer has been studied for the purpose of softening a polylactic acid resin (see, for example, Patent Document 2).

  Usually, when a plasticizer is added for softening, bleeding out is likely to occur. However, according to the invention described in Patent Document 2, it is described that bleeding resistance is greatly improved. . However, when the plasticizer specifically described in Patent Document 2 is used, the heat resistance is lowered. Therefore, when adding a plasticizer, it is possible to achieve both bleed-out resistance and heat resistance. There was a problem that was very difficult.

  In general, in order to obtain a good foam using a resin composition, it is important to increase the melt viscosity of the resin composition as much as possible. In general, it has been considered that it tends to be difficult to obtain a good foam because it leads to a decrease in the melt viscosity of the product.

The foam obtained by solving the various problems as described above can be used for various purposes. For example, automobile parts, electrical / electronic parts, building materials, civil engineering materials, furniture members, and materials for gaming machines. Since it can be used as a foam useful as various daily necessities, it has been strongly desired to solve the above problems.
JP 2001-302835 A (page 2-5) Japanese Patent No. 3421769 (page 3-5)

  Accordingly, an object of the present invention is to provide a foam excellent in heat resistance, light weight and bleed-out resistance.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a foam comprising a resin composition comprising a polylactic acid resin, a natural organic filler and an ester plasticizer having a specific structure. However, the present inventors have found that the present invention exhibits excellent characteristics that meet the above-mentioned purpose, which could not be expected by the present inventors, and reached the present invention.

That is, the present invention
(1) polylactic acid resin, from naturally occurring resin composition bound ester residue in an organic filler and ester groups by blending a structural der Rue ester type plasticizer represented by the following formula (a) of A foam having a foaming ratio of 1.02 to 15 times,
_{- (CH 2 COO) m -} (R 1 O) n -R 2 (a)
(In the formula (a), m represents 0 or 1, n represents an integer of 0 to 6, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and R ² represents a linear chain having 1 to 10 carbon atoms. Or a branched alkyl group, an aryl group having 6 to 12 carbon atoms, an arylalkyl group having 7 to 15 carbon atoms or an alkylaryl group having 7 to 15 carbon atoms, provided that m + n ≧ 1.)
(2) The foam according to (1), wherein the naturally-derived organic filler is at least one selected from paper powder, wood powder, or kenaf fiber, having an ash content of 1% by weight to 30% by weight. ,
(3) The foam according to (1), wherein 50% by weight or more of the natural organic filler is waste paper powder,
(4) A resin composition in which the ester plasticizer is either a plasticizer in which the ester residue is bonded to an ester group of adipic acid ester or a plasticizer in which the ester residue is bonded to an ester group of citrate ester The foam according to (1), comprising
(5) The foam according to (1), wherein the crystallization temperature (Tc) at the time of cooling derived from the polylactic acid resin is 100 ° C. or higher.
(6) The foam according to (1), wherein the naturally-derived organic filler contains paper powder, and the paper powder contains at least one selected from aluminum, silicon, calcium, sulfur, magnesium, and titanium. body,
(7) The resin composition comprises 1 to 350 parts by weight of a naturally derived organic filler and 0.1 to 40 parts by weight of the ester plasticizer with respect to 100 parts by weight of the polylactic acid resin. The foam according to (1),
(8) The foam according to (1), wherein the ester plasticizer is a mixed group ester,
(9) a polylactic acid resin, naturally occurring organic fillers, foaming ester residue linked to the ester group by melt kneading the structure der Rue ester-based plasticizer and blowing agent represented by the following formula (a) It is a manufacturing method of the foam characterized by making into a body.
_{- (CH 2 COO) m -} (R 1 O) n -R 2 (a)
(In the formula (a), m represents 0 or 1, n represents an integer of 0 to 6, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and R ² represents a linear chain having 1 to 10 carbon atoms. Or a branched alkyl group, an aryl group having 6 to 12 carbon atoms, an arylalkyl group having 7 to 15 carbon atoms or an alkylaryl group having 7 to 15 carbon atoms, provided that m + n ≧ 1.)

  The foam of the present invention is excellent in heat resistance, light weight and bleed-out resistance. Further, the foam can be used for various applications such as automobile parts, electrical / electronic parts, building materials, civil engineering materials, furniture members, gaming machine materials, and various daily necessities, taking advantage of the above-mentioned characteristics.

  Hereinafter, the present invention will be described in detail.

  The polylactic acid resin used in the present invention is a polymer mainly composed of L-lactic acid and / or D-lactic acid, but may contain other copolymerization components other than lactic acid. Other monomer units include ethylene glycol, propylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, glycerin, pentaerythritol. Glycol compounds such as bisphenol A, polyethylene glycol, polypropylene glycol and polytetramethylene glycol, oxalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, malonic acid, glutaric acid, cyclohexanedicarboxylic acid, terephthalic acid, Isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4'-diphenyl ether dicarbo Acids, dicarboxylic acids such as 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium isophthalic acid, hydroxycarboxylic acids such as glycolic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxybenzoic acid, and caprolactone And lactones such as valerolactone, propiolactone, undecalactone, and 1,5-oxepan-2-one. Such a copolymer component is preferably contained in an amount of generally 0 to 30 mol%, preferably 0 to 10 mol%, in all monomer components.

  In the present invention, from the viewpoint of heat resistance, it is preferable to use a polylactic acid resin having a high optical purity of the lactic acid component. That is, among the total lactic acid components of the polylactic acid resin, it is preferable that the L isomer is contained at 80% or more, or the D isomer is contained at 80% or more, the L isomer is contained at 90% or more, or the D isomer is 90% or more. It is particularly preferable that the L-form is contained at 95% or more, or the D-form is more preferably contained at 95% or more, the L-form is contained at 98% or more, or the D-form is contained at 98% or more. Further preferred. Moreover, the upper limit of the content of L-form or D-form is usually 100% or less.

  The melting point of the polylactic acid resin is not particularly limited, but is preferably 120 ° C. or higher, more preferably 150 ° C. or higher, and particularly preferably 160 ° C. or higher. The melting point of the polylactic acid resin is usually increased by increasing the optical purity of the lactic acid component, and the polylactic acid resin having a melting point of 120 ° C. or higher contains 90% or more of the L form or 90% or more of the D form. In addition, a polylactic acid resin having a melting point of 150 ° C. or higher can be obtained by containing 95% or more of L-form or 95% or more of D-form. In the present invention, the melting point of the polylactic acid resin is a value measured with a differential scanning calorimeter (DSC) at a heating rate of 20 ° C./min.

  The molecular weight and molecular weight distribution of the polylactic acid resin are not particularly limited as long as it can be substantially molded, but the weight average molecular weight is usually 10,000 or more, preferably 40,000 or more, and further 8 It is desirable to be 10,000 or more. Although there is no restriction | limiting in particular as an upper limit, From a viewpoint of a moldability, it is preferable that it is 500,000 or less. The weight average molecular weight here refers to the molecular weight in terms of polymethyl methacrylate (PMMA) measured by gel permeation chromatography.

  The polylactic acid resin may be modified, for example, maleic anhydride-modified polylactic acid resin, epoxy-modified polylactic acid resin, oxazoline-modified polylactic acid resin, carbodiimide-modified polylactic acid resin, amine-modified polylactic acid resin, etc. Therefore, not only heat resistance but also mechanical characteristics tend to be improved, which is preferable.

  As a method for producing the polylactic acid resin, a known polymerization method can be used, and examples thereof include a direct polymerization method from lactic acid and a ring-opening polymerization method via lactide.

  Any naturally-occurring organic filler used in the present invention can be used as long as it is derived from a natural product, but preferably contains cellulose.

  Specific examples of organic fillers of natural origin include rice husk, wood chips, okara, waste paper pulverized material, clothing pulverized material chips, cotton fiber, hemp fiber, bamboo fiber, wood fiber, kenaf fiber, hemp Fibers such as fiber, jute fiber, banana fiber, coconut fiber, etc., or pulp and cellulose fibers processed from these plant fibers, and fiber such as animal fibers such as silk, wool, Angola, cashmere, camel, paper powder , Powders such as wood powder, bamboo powder, cellulose powder, rice husk powder, fruit shell powder, chitin powder, chitosan powder, protein, and starch. From the viewpoint of heat resistance, paper powder, wood powder, bamboo powder, cellulose powder, rice husk powder, fruit shell powder, chitin powder, chitosan powder, protein powder, starch, etc., cotton fiber, hemp fiber, bamboo fiber , Wood fiber, kenaf fiber, hemp fiber, jute fiber, banana fiber, coconut fiber and other plant fibers are preferable, paper powder, wood powder, bamboo powder, cellulose powder, kenaf fiber, hemp fiber are more preferable, paper powder and wood Powder is more preferred. In addition, kenaf fibers having a high growth rate and a relatively large amount of carbon dioxide absorption are stably available and are preferable from the viewpoint of protecting the global environment. Of these, paper powder is particularly preferable. In addition, these naturally-derived organic fillers may be collected directly from natural products, but from the viewpoint of protecting the global environment and conserving resources, waste materials such as waste paper, waste wood and old clothes are recycled. May be used.

  Waste paper is newspaper, magazine, other recycled pulp, or paperboard such as corrugated cardboard, cardboard, paper tube, etc., as long as it is processed from plant fiber, any of which can be used. From the viewpoint that the effect of improving the properties tends to be high, crushed paperboard such as newspaper and corrugated cardboard, cardboard and paper tube is preferable, and among them, pulverized paperboard such as cardboard, cardboard and paper tube is more preferable.

  Specific examples of the wood include coniferous wood such as pine, cedar, oak, and fir, and broad-leaved wood such as beech, shii, and eucalyptus, and the type is not limited.

  When the natural organic filler is paper powder, the paper powder is made from pulp and contains chemicals commonly used as papermaking raw materials. It is preferable that As the pulp, any of mechanical pulp, semi-chemical pulp, chemical pulp and the like may be used. However, mechanical pulp is likely to be easily improved in formability and heat resistance, and dioxins are less likely to be generated. Is preferred. In addition, as pulp, not only wood pulp, but also non-wood such as kenaf, bagasse, bamboo, flax, cannabis, manila hemp, jute, kozo, mitsumata, ganpi, straw, cotton, etc. Either pulp or waste paper pulp may be used.

  Examples of chemicals commonly used as a raw material for papermaking include sizing agents such as rosin, alkyl ketene dimer, and alkenyl succinic anhydride, paper strength enhancers such as polyacrylamide and starch, polyethylene Yield improvers such as imines, polymer flocculants, drainage improvers, deinking agents such as nonionic surfactants, slime control agents such as organic halogens, pitch control agents such as organic or enzyme-based, Organic substances such as bleaching agents such as hydrogen oxide, ozone, oxygen, chlorine dioxide and sodium hypochlorite, cleaning agents, antifoaming agents, pigment dispersants and lubricants, aluminum sulfate used as a fixing agent for sizing agents, poly Aluminum chloride, and other sodium hydroxide, magnesium hydroxide, and sodium sulfate used as raw materials for papermaking , Sodium silicate, aluminum chloride, may comprise an inorganic material such as chlorine sodium preferred.

  When the naturally-derived organic filler is paper powder, the paper powder is not particularly limited, but preferably contains an adhesive because it tends to increase the heat resistance improvement effect. . The adhesive is not particularly limited as long as it is usually used when processing paper. Emulsion adhesives such as vinyl acetate resin emulsions and acrylic resin emulsions, polyvinyl alcohol adhesives, Examples include cellulose-based adhesives, natural rubber-based adhesives, starch paste, and hot-melt adhesives such as ethylene-vinyl acetate copolymer resin-based adhesives and polyamide-based adhesives. Emulsion-based adhesives, polyvinyl alcohol-based adhesives An adhesive and a hot melt adhesive are preferable, and an emulsion adhesive and a polyvinyl alcohol adhesive are more preferable. These adhesives are also used as binders for paper processing agents. Adhesives include clay, talc, kaolinite, montmorillonite, mica, synthetic mica, zeolite, silica, graphite, carbon black, magnesium oxide, calcium oxide, titanium oxide, calcium sulfide, magnesium carbonate, calcium carbonate, and barium carbonate. Inorganic fillers such as barium sulfate, aluminum oxide and neodymium oxide are preferably contained, and clay, talc, kaolinite, montmorillonite, synthetic mica and silica are more preferable.

  In the present invention, the ash content of the naturally derived organic filler is not particularly limited, but is preferably 1% by weight or more from the viewpoint that the effect of improving moldability and heat resistance tends to be high, and is preferably 5% by weight. Preferably, it is preferably 5.5% by weight or more, more preferably 7.5% by weight or more, and particularly preferably 8% by weight or more. If it is less than 1% by weight, the effect of improving moldability and heat resistance tends to be small. The upper limit is not particularly limited, but is preferably 60% by weight or less, and more preferably 30% by weight or less. Here, the ash content is the weight of the remaining ash content when the natural organic filler is baked for 8 hours at a high temperature of 450 ° C. or higher using an electric furnace or the like with respect to the weight of the natural organic filler before baking. It is a ratio.

  The naturally-occurring organic filler preferably contains at least one selected from aluminum, silicon, calcium, sulfur, magnesium, and titanium from the viewpoint that heat resistance tends to be high. More preferably, all of them are included, more preferably all of aluminum, silicon, calcium and sulfur are included, and particularly preferably all of aluminum, silicon, calcium, sulfur and magnesium are included.

  The naturally-derived organic filler contains aluminum and magnesium from the viewpoint of heat resistance, and the amount of aluminum is preferably larger than the amount of magnesium, and contains aluminum, silicon and magnesium. More preferably, the amount of each of aluminum and silicon is greater than the amount of magnesium, and includes aluminum, silicon, calcium and magnesium, and the amount of each of aluminum, silicon and calcium is greater than the amount of magnesium. Further preferred.

  As the naturally-derived organic filler, the abundance ratio of aluminum, silicon, calcium, sulfur, magnesium, and titanium is not particularly limited. For example, when the total number of the above elements is 100, aluminum is 1 -60%, silicon 20-90%, calcium 1-30%, sulfur 1-20%, magnesium 0-20%, titanium 0-20%, aluminum 1-50% More preferably, silicon is 20 to 85%, calcium is 1 to 20%, sulfur is 1 to 15%, magnesium is 0 to 10%, titanium is 0 to 10%, aluminum is 3 to 50%, silicon Is more preferably 25 to 80%, calcium is 3 to 20%, sulfur is 2 to 10%, magnesium is 0 to 8%, and titanium is 0 to 3%. About these elemental analysis, although it can measure even if it uses either the simple substance of a natural origin organic filler, and the ash content of a natural origin organic filler, in this invention, it shall measure using ash content. . Elemental analysis is measured by using an apparatus combining X-ray fluorescence analysis, atomic absorption spectrometry, scanning electron microscope (SEM) or transmission electron microscope (TEM) and energy dispersive X-ray microanalyzer (XMA). However, in the present invention, it is a value measured using fluorescent X-ray analysis. The naturally-derived organic filler used in the present invention contains various elements as a result of undergoing various treatments and the inherent components.

  When the naturally-derived organic filler is paper powder, it is preferable to include cellulose to which fine particles adhere on the surface from the viewpoint that the effect of improving heat resistance tends to be high. The fine particles are not particularly limited, and may be organic or inorganic. The shape of the fine particles may be any of a needle shape, a plate shape, and a spherical shape. The size of the fine particles is not particularly limited, but is preferably distributed in the range of 0.1 to 5000 nm, more preferably in the range of 0.3 to 1000 nm. More preferably, it is distributed in the range of ˜500 nm, particularly preferably in the range of 1 to 100 nm, and most preferably in the range of 1 to 80 nm. Here, “distributed” in a specific range means that 80% or more of the total number of fine particles is included in the specific range. The adhesion form of the fine particles may be either in an aggregated state or a dispersed state, but is more preferably adhered in a dispersed state. The size of the fine particles can be observed by a transmission electron microscope at a magnification of 80,000 times with a molded product obtained from a resin composition in which a polylactic acid resin and a natural organic filler are blended.

  Naturally-derived organic fillers that have been surface-treated may be used, such as alkali treatment, heat treatment, acetylation treatment, cyanoethylation treatment, silane coupling treatment, and glyogisal treatment. It is preferable to use this organic filler because it tends to improve not only heat resistance but also mechanical properties.

  Moreover, in this invention, as long as the resin composition of this invention is obtained, the organic filler derived from a natural product can be used by 1 type (s) or 2 or more types, It should contain the paper powder which has the said preferable characteristic. Is preferred. Moreover, it is preferable that 50 wt% or more of waste paper powder is contained in the natural organic filler used.

  In the present invention, the blending amount of the naturally derived organic filler is not particularly limited, but from the viewpoint of heat resistance, it is 1 to 350 parts by weight when the polylactic acid resin is 100 parts by weight. Is preferred, more preferably 1 to 300 parts by weight, still more preferably 10 to 200 parts by weight, particularly preferably 30 to 150 parts by weight, and most preferably 60 to 100 parts by weight. If the blending amount of the natural organic filler is less than 1 part by weight, the effect of improving the heat resistance of the polylactic acid resin tends to be small, and if it exceeds 350 parts by weight, the natural organic filler is added to the polylactic acid. It becomes difficult to disperse uniformly in the resin, and in addition to heat resistance, the strength and appearance of the material tend to decrease.

In the present invention, wherein the ester residue attached to the ester group is incorporated structural der Rue ester type plasticizer represented by the following formula (a).
_{- (CH 2 COO) m -} (R 1 O) n -R 2 (a)
(In the formula (a), m represents 0 or 1, n represents an integer of 0 to 6, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and R ² represents a linear chain having 1 to 10 carbon atoms. Or a branched alkyl group, an aryl group having 6 to 12 carbon atoms, an arylalkyl group having 7 to 15 carbon atoms or an alkylaryl group having 7 to 15 carbon atoms, provided that m + n ≧ 1.)

In the above formula, n is preferably an integer of 0 to 5, more preferably an integer of 1 to 4, further preferably 2 to 3, and R ¹ is an alkylene group having 2 to 5 carbon atoms. is preferably, more preferably an alkylene group having 2 to 4 carbon atoms, R ² is a linear or branched alkyl group, an aryl group having 6 to 10 carbon atoms having 1 to 7 carbon atoms, carbon It is preferably an arylalkyl group having 7 to 12 carbon atoms or an alkylaryl group having 7 to 12 carbon atoms, a linear alkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 8 carbon atoms, or 7 to 7 carbon atoms. It is more preferably an arylalkyl group having 9 or an alkylaryl group having 7 to 9 carbon atoms. Here, the ester residue means a portion bonded to an oxygen atom of various ester groups such as a carboxylic acid ester group and a phosphoric acid ester group.

  As the ester plasticizer of the present invention, succinic acid ester, adipic acid ester, azelaic acid ester, sebacic acid ester can be used as long as the ester residue has an ester group having the structure represented by the above formula (a). Aliphatic polybasic acid ester plasticizers such as fumaric acid ester, maleic acid ester and citric acid ester, aliphatic monobasic acid ester plasticizer, phthalic acid ester plasticizer, trimellitic acid ester plasticizer and phosphorus Any ester plasticizers such as acid ester plasticizers may be used, but aliphatic polybasic acid ester plasticizers and phosphate ester plasticizers in that they tend to improve heat resistance and bleed-out resistance. It is preferably an aliphatic polybasic acid ester plasticizer, more preferably an adipic acid ester plasticizer Citric ester plasticizers are more preferred.

  When the ester plasticizer of the present invention has a plurality of ester groups such as an aliphatic polybasic acid ester plasticizer, the ester residue in at least one ester group has the above formula (a). Any ester group having a structure represented by formula (a) may be used, and in all ester groups, the ester residue may be an ester group having a structure represented by the above formula (a). Moreover, although all the ester groups may be the same, it is more preferable that they are mixed-group esters in which the structure of each ester group is different from the viewpoint that the bleed-out resistance tends to be improved.

  When the ester plasticizer is an aliphatic polybasic acid ester plasticizer, it is an ester compound obtained by reacting an aliphatic polybasic acid with an alcohol.

  Examples of the aliphatic polybasic acid include oxalic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, citric acid and the like. From the viewpoint of bleed-out resistance, succinic acid, adipic acid, citric acid and the like. Acid is preferred.

  Examples of the alcohol include methanol, ethanol, 1-butanol, benzyl alcohol, ethylene glycol monomethyl ether (also known as methyl glycol), ethylene glycol monoethyl ether (also known as ethyl glycol), and ethylene glycol monobutyl ether (also known as butyl glycol). , Ethylene glycol monophenyl ether (also known as phenyl glycol), diethylene glycol monomethyl ether (also known as methyl diglycol), diethylene glycol monoethyl ether (also known as ethyl diglycol), diethylene glycol monobutyl ether (also known as butyl diglycol), diethylene glycol monophenyl Ether (also known as phenyl diglycol), triethylene glycol monomethyl ether ( Name: methyl triglycol), triethylene glycol monoethyl ether (also known as ethyl triglycol), triethylene glycol monobutyl ether (also known as butyl triglycol), triethylene glycol monophenyl ether (also known as phenyl triglycol), propylene glycol Monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monophenyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monophenyl ether, tripropylene glycol monomethyl Ether, tripropylene glycol monoethyl ether , Tripropylene glycol monobutyl ether, tripropylene glycol monophenyl ether, etc. In terms of bleed-out resistance, diethylene glycol monomethyl ether (also known as methyl diglycol), diethylene glycol monoethyl ether (also known as ethyl diglycol), diethylene glycol Monobutyl ether (also known as butyl diglycol), triethylene glycol monomethyl ether (also known as methyl triglycol), triethylene glycol monoethyl ether (also known as ethyl triglycol), and triethylene glycol monobutyl ether (also known as butyl triglycol) Diethylene glycol monomethyl ether (also known as methyl diglycol), diethylene glycol monoethyl ether (Also known as ethyl diglycol) and diethylene glycol monobutyl ether (also known as butyl diglycol) are more preferred.

  Specific examples of the aliphatic polybasic acid ester plasticizer include bis (methyl diglycol) succinate, bis (butyl diglycol) succinate, methyl diglycol butyl diglycol succinate, ethyl diglycol butyl diglycol succinate, Propyl diglycol butyl diglycol succinate, benzyl methyl diglycol succinate, methoxycarbonylmethyl methyl diglycol succinate, ethoxycarbonylmethyl methyl diglycol succinate, benzyl butyl diglycol succinate, bis (methyldiglycol) adipate, bis (Butyl diglycol) adipate, methyl diglycol butyl diglycol adipate, ethyl diglycol butyl diglycol adipate, propyl diglycol Butyl diglycol adipate, benzyl methyl diglycol adipate, benzyl butyl diglycol adipate, methoxycarbonylmethyl methyl diglycol adipate, methoxycarbonylmethyl butyl diglycol adipate, ethoxycarbonylmethyl methyl diglycol adipate, ethoxycarbonylmethyl butyl diglycol adipate, dimethyl Diglycol monobutyl diglycol citrate, benzyldimethyl diglycol citrate, methoxycarbonylmethyl dimethyl citrate, methoxycarbonylmethyl diethyl citrate, methoxycarbonylmethyl dibutyl citrate, ethoxycarbonylmethyl dimethyl citrate, ethoxycarbonylmethyl dibutyl citrate , Ethoxycarbo Rumethyldioctyl citrate, butoxycarbonylmethyl dimethyl citrate, butoxycarbonylmethyl diethyl citrate, butoxycarbonylmethyl dibutyl citrate, dimethoxycarbonylmethyl monomethyl citrate, dimethoxycarbonylmethyl monoethyl citrate, dimethoxycarbonylmethyl monobutyl citrate, Diethoxycarbonylmethyl monomethyl citrate, diethoxycarbonylmethyl monobutyl citrate, diethoxycarbonylmethyl monooctyl citrate, dibutoxycarbonylmethyl monomethyl citrate, dibutoxycarbonylmethyl monoethyl citrate, dibutoxycarbonylmethyl monobutyl site Rate, ethoxycarbonylmethyldimethyldiglycol Cytolate, ethoxycarbonylmethyl dibutyl diglycol citrate, diethoxycarbonylmethyl monomethyl diglycol citrate, diethoxycarbonylmethyl monobutyl diglycol citrate, etc., among them methyl diglycol butyl diglycol succinate, benzyl methyl Diglycol succinate, benzyl butyl diglycol succinate, methyl diglycol butyl diglycol adipate, benzyl methyl diglycol adipate, benzyl butyl diglycol adipate, methoxycarbonylmethyl dibutyl citrate, ethoxycarbonylmethyl dibutyl citrate, butoxycarbonylmethyl dibutyl Cytolate, dimethoxycarbonylmethyl monobutyl citrate, diet Aryloxycarbonyl methyl monobutyl citrate, jib butoxycarbonyl methyl monobutyl citrate are preferable.

  Among the ester plasticizers, methyl diglycol butyl diglycol adipate, benzyl methyl diglycol adipate, benzyl butyl diglycol adipate, and ethoxycarbonylmethyl dibutyl citrate are most preferable.

  In this invention, the said ester plasticizer can be used by 1 type (s) or 2 or more types.

  The amount of the ester plasticizer is not particularly limited, but from the viewpoint of heat resistance, when the polylactic acid resin is 100 parts by weight, it is preferably 0.1 to 40 parts by weight, The amount is more preferably 1 to 30 parts by weight, further preferably 2 to 25 parts by weight, particularly preferably 3 to 20 parts by weight, and most preferably 5 to 12 parts by weight. When the ester plasticizer is less than 0.1 parts by weight or more than 40 parts by weight, the heat resistance improvement effect of the polylactic acid resin tends to be reduced, and the strength and appearance as a material may be reduced. There is sex.

  Although the molecular weight of the said ester plasticizer is not specifically limited, 200-1500 are preferable and 300-1000 are more preferable. If the molecular weight is less than 200, bleeding out tends to occur and blocking or the like tends to occur, and if it exceeds 1500, the effect of improving the heat resistance of the polylactic acid resin tends to be reduced.

  In the present invention, it is preferable to use a foaming agent in order to obtain a foam.

  Any foaming agent may be used as long as it can be used to obtain a foam. Chemical foaming agents, physical foaming agents, and the like can be used, and the foam of the present invention can be suitably obtained. A chemical foaming agent is preferred in terms of easy control of magnification and bubbles.

  Chemical foaming agents include azo compounds such as azodicarbonamide, azobisisobutyronitrile, barium azodicarboxylate, hydrazide compounds such as 4,4′-oxybisbenzenesulfonyl hydrazide and p-toluenesulfonyl hydrazide, dinitrosopenta Nitroso compounds such as methylenetetramine, hydrazo compounds such as hydrazodicarbonamide, 5-phenyltetrazole, 5-aminotetrazole, azobistetrazole, bistetrazole and other tetrazole compounds, hydrazodicarboxylic acid esters, azodicarboxylic acid esters, Examples thereof include ester compounds such as citric acid esters, isocyanate compounds, sodium bicarbonate, sodium carbonate, and the like, and azodicarbonamide and azobis Preferred are azo compounds such as butyronitrile and barium azodicarboxylate, tetrazole compounds such as 5-phenyltetrazole, 5-aminotetrazole, azobistetrazole, and bistetrazole, and isocyanate compounds, and azodicarbonamide and azobisisobutyridine. Azo compounds such as nitrile and barium azodicarboxylate are more preferred, and azodicarbonamide is more preferred.

  Physical foaming agents include ethane, butane, pentane, hexane, heptane, ethylene, propylene, petroleum ether, methyl chloride, monochlorotrifluoromethane, dichlorodifluoromethane, dichlorotetrafluoroethane, water, air, carbon dioxide, nitrogen gas Butane, pentane, hexane, water, air, carbon dioxide gas, nitrogen gas are preferred, water, air, carbon dioxide gas, nitrogen gas are more preferred, water, air, Carbon dioxide gas is more preferable. In addition, it is preferable to use a substance that can be used as a supercritical fluid such as carbon dioxide gas or nitrogen gas as a foaming agent in a supercritical fluid state because a foam that does not decrease in strength can be obtained.

  The addition amount of the foaming agent may be an effective amount for obtaining the expansion ratio specified in the present invention, and varies slightly depending on the type, but is 0.01 to 18 parts by weight with respect to 100 parts by weight of the polylactic acid resin. It is preferably 0.1 to 15 parts by weight, more preferably 0.5 to 10 parts by weight. If the amount is too small, the effect of the foaming agent is not sufficient, and if the amount is too large, the surface appearance tends to be impaired.

  In the present invention, in order to stabilize the foaming behavior and obtain a foam having good foaming ratio, foam density and cell size, as a foaming aid, metal oxides such as zinc oxide, calcium oxide and aluminum oxide, stearin It is preferable to blend an aliphatic salt such as zinc oxide, calcium stearate, magnesium stearate, aluminum stearate calcium montanate, magnesium montanate, aluminum montanate, paraffin, talc, calcium carbonate, mica, silica, kaolin, and the like.

  The amount of the foaming aid added is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, and more preferably 0.1 to 1 part per 100 parts by weight of the polylactic acid resin. More preferably, it is part by weight. If the amount is less than 0.01 part by weight, the effect of adding the foaming aid is not sufficient, and if it exceeds 10 parts by weight, the surface appearance tends to be impaired.

  In the present invention, within the range that does not impair the effects of the present invention, crystal nucleating agent, thermoplastic resin other than polylactic acid resin, filler other than organic filler derived from nature, carboxyl group reactive end-blocking agent, stabilizer, Release agents, flame retardants, antistatic agents, lubricants, UV absorbers (benzophenone compounds, benzotriazole compounds, aromatic benzoate compounds, oxalic acid anilide compounds, cyanoacrylate compounds and hindered amine compounds), sliding properties Other components usually added to resins such as improvers (graphite, fluororesins, etc.), antibacterial agents, colorants including pigments and dyes, plasticizers other than ester plasticizers blended in the present invention, and weathering agents More than seeds can be added.

  In the present invention, it is preferable to blend a crystal nucleating agent. By blending the crystal nucleating agent, a foam excellent in moldability and heat resistance can be obtained.

  As the crystal nucleating agent used in the present invention, those generally used as a resin crystal nucleating agent can be used without particular limitation, and any of an inorganic crystal nucleating agent and an organic crystal nucleating agent can be used. .

  Specific examples of inorganic crystal nucleating agents include talc, kaolin, montmorillonite, synthetic mica, clay, zeolite, silica, graphite, carbon black, zinc oxide, magnesium oxide, titanium oxide, calcium sulfide, boron nitride, calcium carbonate, sulfuric acid Examples thereof include metal salts of barium, aluminum oxide, neodymium oxide and phenylphosphonate. These inorganic crystal nucleating agents are preferably modified with an organic substance in order to enhance dispersibility in the composition.

  Specific examples of the organic crystal nucleating agent include sodium benzoate, potassium benzoate, calcium benzoate, magnesium benzoate, lithium terephthalate, sodium terephthalate, calcium oxalate, sodium laurate, sodium stearate, stearin. Organic carboxylic acid metal salts such as potassium acid, magnesium stearate, sodium montanate, calcium montanate, organic sulfonates such as sodium p-toluenesulfonate, sodium sulfoisophthalate, stearic acid amide, ethylenebislauric acid amide, Of organic carboxylic acid amides such as palmitic acid amide, hydroxystearic acid amide, erucic acid amide, trimesic acid tris (t-butylamide), ethylene-acrylic acid or methacrylic acid copolymer Sodium salt or potassium salt of a polymer having a carboxyl group such as thorium salt (so-called ionomer), benzylidene sorbitol and its derivatives, sodium-2,2′-methylenebis (4,6-di-t-butylphenyl) phosphate, etc. And phosphorus compound metal salts.

  As the crystal nucleating agent used in the present invention, among those exemplified above, at least one selected from talc, organic carboxylic acid metal salts and organic carboxylic acid amides is particularly preferable. The crystal nucleating agent used in the present invention may be used alone or in combination of two or more.

  Moreover, the compounding quantity of a crystal nucleating agent has the preferable range of 0.01-50 weight part with respect to 100 weight part of polylactic acid resin, The range of 0.05-25 weight part is more preferable, 0.1-10 A range of parts by weight is more preferred.

  In the present invention, it is preferable to blend a thermoplastic resin other than the polylactic acid resin. By blending a thermoplastic resin other than the polylactic acid resin, a foam excellent in surface appearance, moldability, mechanical properties, heat resistance, toughness, and the like can be obtained.

  In the present invention, the thermoplastic resin is not particularly limited, and is a polyacetal resin, a polyester resin other than polylactic acid, a polyolefin resin such as a polyamide resin, a polyethylene resin and a polypropylene resin, a polystyrene resin, an acrylic resin, and a polyurethane resin. , Chlorinated polyethylene resin, chlorinated polypropylene resin, aromatic and aliphatic polyketone resin, fluorine resin, polyphenylene sulfide resin, polyether ether ketone resin, polyimide resin, thermoplastic starch resin, AS resin, ABS resin, AES resin, ACS Resin, polyvinyl chloride resin, polyvinylidene chloride resin, vinyl ester resin, MS resin, polycarbonate resin, polyarylate resin, polysulfone resin, polyethersulfone resin, phenoxy resin, Examples include thermoplastic resins such as rephenylene oxide resin, poly-4-methylpentene-1, polyetherimide resin, cellulose acetate resin, and polyvinyl alcohol resin. Among them, polyacetal resin, polyester resin other than polylactic acid, polyamide resin It is preferable to mix at least one selected from the group consisting of polyester resins other than polylactic acid resins.

  The polyester resin other than the polylactic acid resin is not particularly limited, and any of aliphatic polyester resin, alicyclic polyester resin, aromatic polyester resin, aliphatic aromatic polyester resin, etc. can be used. An aliphatic polyester resin or an aliphatic aromatic polyester resin is preferred because the impact resistance of the body tends to be improved and the bubble size tends to be easily controlled. Examples of the aliphatic polyester include polyethylene succinate, polybutylene succinate, polybutylene adipate, polyethylene adipate, polybutylene (succinate / adipate), polyethylene (succinate / adipate) and the like. Examples of the aliphatic aromatic polyester resin include polybutylene (terephthalate / succinate), polyethylene (terephthalate / succinate), polybutylene (terephthalate / adipate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sulfoisophthalate / adipate), Examples include polybutylene (terephthalate / sebacate), polyethylene (terephthalate / sebacate), and the like.

  Moreover, in this invention, an impact resistance improving agent can also be mix | blended as thermoplastic resins other than a polylactic acid resin. By blending the impact resistance improver, a foam excellent in impact resistance, toughness, moldability and heat resistance can be obtained.

  The impact resistance improver used in the present invention is not particularly limited as long as it can be used for improving the impact resistance of a thermoplastic resin. For example, at least one selected from the following various impact resistance improvers can be used.

  That is, specific examples of impact modifiers include ethylene-propylene copolymers, ethylene-propylene-nonconjugated diene copolymers, ethylene-butene-1 copolymers, various acrylic rubbers, ethylene-acrylic acid copolymers. And alkali metal salts thereof (so-called ionomers), ethylene-glycidyl (meth) acrylate copolymers, ethylene-alkyl acrylate copolymers (for example, ethylene-ethyl acrylate copolymers, ethylene-butyl acrylate copolymers) ), Acid-modified ethylene-propylene copolymer, diene rubber (for example, polybutadiene, polyisoprene, polychloroprene), copolymer of diene and vinyl monomer (for example, styrene-butadiene random copolymer, styrene-butadiene block copolymer) Coalescence, styrene-butadiene Styrene block copolymer, styrene-isoprene random copolymer, styrene-isoprene block copolymer, styrene-isoprene-styrene block copolymer, polybutadiene grafted with styrene, butadiene-acrylonitrile copolymer) , Polyisobutylene, a copolymer of isobutylene and butadiene or isoprene, natural rubber, thiocol rubber, polysulfide rubber, polyurethane rubber, polyether rubber, epichlorohydrin rubber and the like.

  Furthermore, it is composed of those having various degrees of cross-linking, various micro structures such as those having a cis structure, a trans structure, etc., those having a vinyl group, etc., a core layer and one or more shell layers covering it, A so-called core-shell type multi-layered polymer in which adjacent layers are made of different polymers can also be used.

  The various (co) polymers mentioned in the above specific examples may be any of random copolymers, block copolymers and graft copolymers, and can be used as the impact resistance improver of the present invention. it can.

  Furthermore, in making these (co) polymers, it is also possible to copolymerize monomers such as other olefins, dienes, aromatic vinyl compounds, acrylic acid, acrylic ester and methacrylic ester. is there.

  Among these impact modifiers, a polymer containing an acrylic unit and a polymer containing a unit having an acid anhydride group and / or a glycidyl group are preferable. Preferable examples of the acrylic unit herein include methyl methacrylate units, methyl acrylate units, ethyl acrylate units and butyl acrylate units. Preferred examples of units having an acid anhydride group or glycidyl group May include maleic anhydride units and glycidyl methacrylate units.

  The impact resistance improver is a so-called core-shell type multi-layer polymer composed of a core layer and one or more shell layers covering the core layer, and adjacent layers are composed of different polymers. It is preferable that the polymer is a multilayer structure polymer containing methyl methacrylate units or methyl acrylate units in the shell layer. Such a multilayer structure polymer preferably contains an acrylic unit, or preferably contains a unit having an acid anhydride group and / or a glycidyl group. Preferred examples of the acrylic unit include a methyl methacrylate unit, an acrylic acid A methyl unit, an ethyl acrylate unit, and a butyl acrylate unit can be mentioned, As a suitable example of a unit which has an acid anhydride group and a glycidyl group, a maleic anhydride unit and a glycidyl methacrylate unit can be mentioned. In particular, the shell layer contains at least one selected from methyl methacrylate units, methyl acrylate units, maleic anhydride units and glycidyl methacrylate units, and includes butyl acrylate units, ethyl hexyl acrylate units, styrene units and butadiene units. A multilayer structure containing at least one selected from the above in the core layer is preferably used.

  The glass transition temperature of the impact resistance improver is preferably −20 ° C. or lower, and more preferably −30 ° C. or lower.

  The blending amount of the thermoplastic resin other than the polylactic acid resin in the present invention is preferably in the range of 0.5 to 120 parts by weight, and in the range of 1 to 100 parts by weight with respect to 100 parts by weight of the polylactic acid resin. More preferably, it is more preferable that it is the range of 3-70 weight part, and it is especially preferable that it is the range of 5-50 weight part.

  In the present invention, fillers other than naturally derived organic fillers may be blended. As fillers other than naturally-derived organic fillers, inorganic fillers are preferably blended. As the inorganic filler used in the present invention, fibers, plates, granules, and powders that are usually used for reinforcing thermoplastic resins can be used. Specifically, glass fiber, asbestos fiber, carbon fiber, graphite fiber, metal fiber, potassium titanate whisker, aluminum borate whisker, magnesium-based whisker, silicon-based whisker, wollastonite, sepiolite, asbestos, slag fiber, zonolite, Elastadite, gypsum fiber, silica fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber and boron fiber and other inorganic fillers, glass flakes, non-swellable mica, swellable mica, graphite, metal foil , Ceramic beads, talc, clay, mica, sericite, zeolite, bentonite, organic modified bentonite, organic modified montmorillonite, dolomite, kaolin, fine powdered silicic acid, feldspar powder, potassium titanate, shirasu balloon, calcium carbonate , Magnesium carbonate, barium sulfate, calcium oxide, aluminum oxide, titanium oxide, aluminum silicate, silicon oxide, gypsum, novaculite, include plate-like or granular inorganic fillers such as dawsonite and white clay. Among these inorganic fillers, glass fiber, wollastonite, mica and kaolin are particularly preferable. The aspect ratio of the fibrous filler is preferably 5 or more, more preferably 10 or more, and further preferably 20 or more.

  The inorganic filler may be coated or focused with a thermoplastic resin such as an ethylene / vinyl acetate copolymer or a thermosetting resin such as an epoxy resin, or a coupling agent such as aminosilane or epoxysilane. May be processed.

  Moreover, 1-100 weight part is preferable with respect to 100 weight part of polylactic acid resin, and, as for the compounding quantity of an inorganic filler, 5-50 weight part is more preferable.

  In this invention, it is preferable to mix | blend a carboxyl group reactive terminal blocker at the point that durability can be improved. The carboxyl group-reactive end-blocking agent used in the present invention is not particularly limited as long as it is a compound that can block the carboxyl end group of the polymer, and those used as the carboxyl-terminal blocking agent of the polymer are used. be able to. In the present invention, the carboxyl group-reactive end-blocking agent not only blocks the end of the polylactic acid resin, but also generates lactic acid, formic acid, etc. produced by thermal decomposition or hydrolysis of the polylactic acid resin or naturally-occurring organic filler. The carboxyl group of the acidic low molecular weight compound can also be blocked. Further, the end-capping agent is more preferably a compound that can also block the hydroxyl end where an acidic low molecular weight compound is generated by thermal decomposition.

  As such a carboxyl group-reactive end-blocking agent, it is preferable to use at least one compound selected from an epoxy compound, an oxazoline compound, an oxazine compound, and a carbodiimide compound, and among them, an epoxy compound and / or a carbodiimide compound are preferable. .

  0.01-10 weight part is preferable with respect to 100 weight part of polylactic acid resin, and, as for the quantity of a carboxyl group reactive terminal blocker, 0.05-5 weight part is further more preferable.

  The timing of addition of the carboxyl group-reactive end-blocking agent is not particularly limited, but it is naturally derived after pre-melting and kneading with a polylactic acid resin in terms of not only improving heat resistance but also improving mechanical properties and durability. It is preferable to knead with the organic filler.

  In the present invention, it is preferable to further add a reaction catalyst of a carboxyl group reactive end-blocking agent. The reaction catalyst referred to here is a compound that has an effect of promoting the reaction between the carboxyl group-reactive end-blocking agent and the polymer end or the acidic group of the acidic low-molecular compound, and has the effect of promoting the reaction with a small amount of addition. Certain compounds are preferred. Examples of such compounds include alkali metal compounds, alkaline earth metal compounds, tertiary amine compounds, imidazole compounds, quaternary ammonium salts, phosphine compounds, phosphonium salts, phosphate esters, organic acids, Lewis acids. .

  The addition amount of the reaction catalyst is not particularly limited, but is preferably 0.001 to 1 part by weight, more preferably 0.01 to 0.5 part by weight based on 100 parts by weight of the polylactic acid resin. Furthermore, 0.02-0.3 weight part is the most preferable.

  In the present invention, a stabilizer is preferably blended from the viewpoint that a foam excellent in mechanical properties, heat resistance, durability and the like can be obtained. As stabilizers, those usually used as stabilizers for thermoplastic resins can be used, but UV absorbers (benzophenone compounds, benzotriazole compounds, aromatic benzoate compounds, oxalic acid anilide compounds, cyanoacrylate compounds) Compounds and hindered amine compounds), heat stabilizers (hindered phenol compounds, phosphite compounds, thioether compounds) and the like are preferable. The blending amount of the stabilizer is preferably 0.01 to 3 parts by weight, and more preferably 0.03 to 2 parts by weight with respect to 100 parts by weight of the polylactic acid resin.

  In the present invention, a mold release agent is preferably blended from the viewpoint that a foam excellent in mechanical properties, moldability, heat resistance, durability and the like can be obtained. As the mold release agent, those usually used for mold release agents for thermoplastic resins can be used. Specifically, fatty acids, fatty acid metal salts, oxy fatty acids, fatty acid esters, partially aliphatic saponified esters, paraffin, low molecular weight polyolefins, fatty acid amides, alkylene bis fatty acid amides, aliphatic ketones, fatty acid lower alcohol esters, fatty acid polyhydric alcohols Examples thereof include esters, fatty acid polyglycol esters, and modified silicones. By blending these, a molded product having excellent mechanical properties, moldability, heat resistance and durability can be obtained. The compounding amount of the release agent is preferably 0.01 to 3 parts by weight, more preferably 0.03 to 2 parts by weight with respect to 100 parts by weight of the polylactic acid resin.

  In this invention, it is preferable to mix | blend a flame retardant with the point that a flame retardance can be provided. In the present invention, the flame retardant is not particularly limited as long as it is a substance added for the purpose of imparting flame retardancy to the resin, and a known one can be used. Specific examples include brominated flame retardants, chlorine-based flame retardants, phosphorus-based flame retardants, nitrogen compound-based flame retardants, silicone-based flame retardants, and other inorganic flame retardants. It can be used by 1 type (s) or 2 or more types. The flame retardant is preferably a flame retardant having a low environmental impact. Environment-friendly flame retardants include those that are biodegradable, those that do not generate toxic gases during incineration, those that are derived from non-petroleum raw materials such as plant resources, or natural raw materials. Flame retardants, nitrogen compound flame retardants, silicone flame retardants, and other inorganic flame retardants are preferred.

  Among the above flame retardants, it is preferable to use at least one selected from phosphorus flame retardants, nitrogen compound flame retardants, silicone flame retardants, and other inorganic flame retardants. Phosphorus flame retardants, nitrogen compound flame retardants It is more preferable to use a combination of at least two selected from flame retardants, silicone flame retardants and other inorganic flame retardants.

  The blending amount of the flame retardant is 0.01 to 100 parts by weight, more preferably 0.5 to 90 parts by weight, and further preferably 1 to 80 parts by weight with respect to 100 parts by weight of the polylactic acid resin.

  In the present invention, it is preferable to further add an antistatic agent in terms of imparting antistatic properties. Any known antistatic agent can be used in the present invention.

  In the antistatic agent of the present invention, its ionicity is not particularly limited, and any of cationic, anionic, zwitterionic and nonionic may be used, but the thermal decomposition of the polylactic acid resin is suppressed. In terms of being able to be made, zwitterionic and nonionic systems are preferable, and nonionic systems are more preferable.

  Furthermore, it is preferable that the antistatic agent is biodegradable. Examples of such include Riken Master GSR-350 made by Riken Vitamin.

  0.1-10 weight part is preferable with respect to 100 weight part of polylactic acid resin, and, as for the compounding quantity of said antistatic agent, 0.5-5 weight part is further more preferable.

As a method for producing the foam of the present invention, any of a melt foaming method, a solid phase foaming method and a cast foaming method may be used, but the melt foaming method is preferred because it can be easily carried out. Specifically, a foam obtained by melt-kneading a polylactic acid resin, an organic filler derived from nature, an ester plasticizer having an ester group having a structure represented by the following formula (a), and a foaming agent It is what.
_{- (CH 2 COO) m- (} R 1 O) n-R 2 (a)
(In the formula (a), m represents 0 or 1, n represents an integer of 0 to 6, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and R ² represents a linear chain having 1 to 10 carbon atoms. Or a branched alkyl group, an aryl group having 6 to 12 carbon atoms, an arylalkyl group having 7 to 15 carbon atoms or an alkylaryl group having 7 to 15 carbon atoms, provided that m + n ≧ 1.)

  The melt kneading may be performed under normal pressure or under pressure, but is preferably melt-kneaded under pressure and then extruded under atmospheric pressure or injected into a mold to form a foam.

  In the present invention, the method of melt-kneading is not particularly limited. For example, polylactic acid resin, naturally-derived organic filler, ester plasticizer, foaming agent and other additives as necessary are blended in advance, Single-screw extruder, twin-screw extruder, single-screw / double-screw composite extruder, multi-screw extruder, tandem extruder with two single-screws and / or two twin-screws, etc., above the melting point of lactic acid resin Foam extrusion molding method that is uniformly melt-kneaded using an extruder to make an extruded foam, foam injection molding method that is directly melt-kneaded using an injection molding machine to make a foam, and polylactic acid resin uniformly using an extruder, It is preferable to use any method such as a method in which a natural organic filler and an ester plasticizer are melt-kneaded to obtain a resin composition and then blended with a foaming agent to form a foam using a press or an injection molding machine. it can. In addition, when using fine powder as a raw material, the method of adding after compressing a fine powder, the method of supplying to a hopper independently from another additive, etc. are preferable. Moreover, a foaming agent may be mix | blended independently and may be mix | blended after preparing the masterbatch of a foaming agent previously.

  In this invention, 100-250 degreeC is preferable, as for the preset temperature of an extruder or an injection molding machine, 120-240 degreeC is more preferable, 140-230 degreeC is further more preferable, and 160-220 degreeC is the most preferable. The set temperature refers to the cylinder set temperature. The set temperature is set so that the resin temperature, preferably the resin temperature near the inner wall of the cylinder is 160 to 230 ° C., preferably 170 to 210 ° C., more preferably 175 to 200 ° C.

  In the present invention, the screw rotation speed of the extruder or the injection molding machine is not particularly limited, but is preferably 10 to 500 rpm, more preferably 30 to 350 rpm from the viewpoint of suppressing an increase in the resin temperature due to shearing heat generation. 50 to 250 rpm is more preferable, and 70 to 200 rpm is particularly preferable.

  In the present invention, the ratio (L / D) of the length (L) of the screw of the extruder to the diameter (D) of the screw is not particularly limited, but is 20 to 20 from the viewpoint of the dispersibility of the naturally derived organic filler. 80 is preferable, 25 to 70 is preferable, 30 to 60 is more preferable, and 35 to 50 is particularly preferable.

  In the present invention, the mold temperature in the case of foam injection molding is preferably 30 ° C or higher, more preferably 60 ° C or higher, further preferably 70 ° C or higher, from the viewpoint of crystallization, from the viewpoint of deformation of the test piece, 140 degrees C or less is preferable, 120 degrees C or less is more preferable, and 110 degrees C or less is more preferable.

  In the present invention, it is preferable to introduce an inert gas such as nitrogen because a foam having a stable and good color tone can be obtained.

  In the present invention, as a method of supplying raw materials to an extruder or an injection molding machine, a method of directly supplying each raw material individually, a method of supplying all raw materials in a lump after premixing, a Henschel mixer, etc. Either a method of supplying the raw material after making it agglomerated with a high speed mixer or a method of supplying it after pelletizing with an extruder or the like can be used, but operability and dispersion of organic fillers derived from nature From the viewpoint of properties, a method of directly supplying each raw material individually and a method of supplying all raw materials in a lump after premixing them are preferable. Moreover, it is preferable to supply a raw material using a weight feeder from the point of extrusion stability.

  In the present invention, when using a method in which all raw materials are mixed in advance and then fed together, the extruder or injection molding machine can be operated stably, and the dispersibility of the natural organic filler can be increased. It is preferable to blend using a blender such as a V blender, a ribbon blender, a tumbler blender, a screw blender, and a Henschel mixer as premixing because it can be improved. When this method is used, the raw material may be either granular or powdery, but is preferably powdery from the viewpoint of mixing properties.

  The foam of the present invention has a foaming ratio of 1.02 to 15 times. Here, the expansion ratio can be determined from the raw material resin composition density / foam density. The expansion ratio is preferably 1.1 to 12 times, more preferably 1.2 to 10 times, further preferably 1.3 to 8 times, and most preferably 1.4 to 5 times from the viewpoint of heat resistance. . If the expansion ratio is less than 1.02, the lightness is not sufficient, and if it exceeds 15 times, not only the heat resistance is lowered, but also it becomes difficult to obtain a stable product, which is not preferable. The foam having the expansion ratio can be obtained by using a preferable foaming agent in a preferable addition amount and utilizing a preferable manufacturing method. The expansion ratio mainly depends on the amount of the foaming agent. When the amount of the foaming agent used is increased, the expansion ratio tends to increase. On the other hand, the amount of the filler such as a naturally-derived organic filler or inorganic filler is reduced. If it is increased, the expansion ratio tends to decrease. Here, the density of the raw material resin composition means the density of the raw material resin composition in an unfoamed state. If the used raw material is known, it is calculated according to the composition ratio of the used raw material. Can do. Further, even when the raw material used is not known, it can be obtained from a product obtained by solidifying the foamed raw material resin composition as an unfoamed material after the foam is removed.

In the present invention, the lightness can be determined from the foam density. Foam density is not particularly limited but is preferably ^{0.03~1.25g / cm 3, 0.05~0.85g / cm} 3 is more preferable. When foam density is less than 0.05 g / cm ^3, the appearance lead to failure or strength decrease, exceeds 1.25 g / cm ^3, unfavorably effect of weight reduction is small. The foam having the above foam density can be obtained by using a preferable foaming agent in a preferable addition amount and utilizing a preferable manufacturing method. The foam density can be obtained from the weight of the foam (g) / the volume of the foam (cm ³ ) using the weight of the foam and the volume determined by the submerging method.

  The foam size of the foam of the present invention is not particularly limited, but is preferably 0.1 to 2000 μm, more preferably 1 to 700 μm, further preferably 5 to 500 μm, and particularly preferably 10 to 300 μm from the viewpoint of appearance. If the bubble size is less than 0.1 μm, or exceeds 2000 μm, the effect of foaming is impaired, and the appearance is poor and the strength is reduced. The foam having the cell size can be obtained by using a preferable foaming agent and the above-mentioned additives such as a preferable aliphatic aromatic polyester and an inorganic filler in a preferable addition amount and utilizing a preferable production method, for example, The bubble size tends to be reduced by increasing the amount of the inorganic filler, and the bubble size tends to be increased by increasing the amount of the aliphatic aromatic polyester. The bubble size is an average value of arbitrary 10 bubbles, preferably 100 bubbles, in which the inner layer portion of the cross section of the foam can be observed with an optical microscope at 5 times or more, preferably 50 times.

  Further, among the bubbles that can be observed by the above method, the difference between the minimum bubble size and the maximum bubble size is preferably 1500 μm or less, more preferably 1000 μm or less, and further preferably 500 μm or less. If the difference between the minimum bubble size and the maximum bubble size is out of the above range, the effect of foaming is impaired, which leads to poor appearance and reduced strength. The foam having the cell size can be obtained by using a preferable foaming agent and the above-mentioned additives such as a preferable aliphatic aromatic polyester and inorganic filler in a preferable addition amount and utilizing a preferable production method.

  In this invention, it is preferable that the crystallization temperature (Tc) at the time of temperature fall derived from a polylactic acid resin can be observed. Here, Tc is a crystallization temperature at the time of temperature decrease derived from a polylactic acid resin measured at a temperature decrease rate of 20 ° C./min after the temperature was increased to 200 ° C. by a differential scanning calorimeter (DSC). Tc is not particularly limited, but is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, further preferably 105 ° C. or higher, and particularly preferably 110 ° C. or higher from the viewpoint of moldability. The upper limit of Tc is not particularly limited, and the higher the Tc, the better the tendency to have excellent crystallization characteristics. Such a foam having Tc can be obtained by using a polylactic acid resin having a preferred embodiment, a natural organic filler or an ester plasticizer, and more preferably a polylactic acid resin having a preferred embodiment. And by using naturally occurring organic fillers.

  In the present invention, it is preferable that the crystallization temperature (Tcc) at the time of temperature rise derived from the polylactic acid resin is not observed. When Tcc is observed, the crystallization enthalpy (ΔHcc) is preferably 10 J / g or less, more preferably 5 J / g or less, and even more preferably 1 J / g or less. Here, Tcc and ΔHcc are a crystallization temperature and a crystallization enthalpy derived from a polylactic acid resin obtained by measuring a molded product with a differential scanning calorimeter (DSC) at a temperature rising rate of 20 ° C./min.

  In the present invention, the relative crystallinity [{(ΔHm−ΔHcc) / ΔHm} × 100] obtained from the crystal melting enthalpy (ΔHm) derived from polylactic acid resin and the crystallization enthalpy (ΔHcc) at the time of temperature rise is 70% or more, more preferably 90% or more, still more preferably 93% or more, particularly preferably 96% or more, and most preferably 100%. Here, ΔHcc is the crystallization enthalpy derived from polylactic acid resin measured by DSC at a temperature rising rate of 20 ° C./min, and ΔHm is derived from polylactic acid resin measured by DSC at a temperature rising rate of 20 ° C./min. In the first measurement (1stRUN), the temperature was increased from 30 ° C. to 200 ° C. at a temperature increase rate of 20 ° C./min, and then cooled to 30 ° C. at a temperature decrease rate of 20 ° C./min. When the temperature is increased from 30 ° C. to 200 ° C. at a temperature increase rate of 20 ° C./min in the second measurement (2nd RUN), the crystal melting enthalpy measured at 2 nd RUN is preferable.

  The foam having such crystallization characteristics can be made into a foam excellent in heat resistance and dimensional stability, and can be achieved by using a naturally-derived organic filler having the above-mentioned preferred embodiments.

  The foam of the present invention has various shapes such as a board shape, a sheet shape, a film shape, a plate shape, a rod shape, a column shape, a box shape, a lump shape, a tube shape, a fiber shape, a net shape, a particle shape, and a complex shape. Useful as.

  When the foam of the present invention has a board shape, the thickness is preferably 1 to 30 mm, more preferably 2 to 25 mm, and even more preferably 5 to 20 mm. If the thickness is less than 1 mm, the number of bubbles is reduced and the lightness is not sufficient. If the thickness exceeds 30 mm, it is difficult to control the expansion ratio and the bubble size, and it is difficult to obtain a good product having a uniform thickness. Therefore, it is not preferable.

  The foam of the present invention includes automobile parts (interior / exterior parts, etc.), electric / electronic parts (various housings, gears, gears, etc.), building materials, civil engineering materials, furniture members, agricultural materials, game machine materials, tableware, sports It can be used for various purposes such as materials, musical instruments and daily necessities. Especially, it can be used effectively for automobile parts, electrical / electronic parts, building materials, civil engineering materials, furniture materials, and materials for gaming machines from the viewpoint of heat resistance, surface appearance and bleed-out resistance. From the point that it is excellent in batting property, it is more useful as a building material, civil engineering material, furniture member, and game machine material.

  Specifically, automotive parts include air flow meters, air pumps, thermostat housings, engine mounts, ignition hobbins, ignition cases, clutch bobbins, sensor housings, idle speed control valves, vacuum switching valves, ECU housings, vacuum pump cases, inhibitors Switch, rotation sensor, acceleration sensor, distributor cap, coil base, ABS actuator case, radiator tank top and bottom, cooling fan, fan shroud, engine cover, cylinder head cover, oil cap, oil pan, oil filter, fuel cap , Fuel strainer, distributor cap, vapor Nister housing, air cleaner housing, timing belt cover, brake booster parts, various cases, various tubes, various tanks, various hoses, various clips, various valves, various pipes such as automotive underhood parts, torque control lever, safety belt Parts, register blade, washer lever, window regulator handle, knob of window regulator handle, passing light lever, sun visor bracket, door trim, door pocket, column cover, cowl side, footrest deck trim, front pillar, center pillar, front scuff, Rear scuff, door cuff, front outside, rear outside, seat side, roof side, striker, air Automotive interior parts such as concases, cassette deck cases, various motor housings, roof rails, fenders, garnishes, bumpers, door mirror stays, spoilers, hood louvers, wheel covers, wheel caps, grill apron cover frames, lamp reflectors, lamp bezels, Various automotive connectors such as exterior parts for automobiles such as door handles, wire harness connectors, SMJ connectors, PCB connectors, and door grommet connectors. Electrical and electronic components include notebook PC housings and internal parts, CRT display housings and internal parts, printer housings and internal parts, mobile terminal housings and internal parts such as mobile phones, mobile PCs, handheld mobiles, recording media (CD, (DVD, PD, FDD, etc.) Drive housing and internal parts, copier housing and internal parts, facsimile housing and internal parts, parabolic antennas, and other electric / electronic parts. Furthermore, audio equipment parts such as VTR parts, TV parts, irons, hair dryers, rice cooker parts, microwave oven parts, acoustic parts, video cameras, audio / laser disks (registered trademark) / compact disks, lighting parts, refrigerator parts, Household and office electrical product parts represented by air conditioner parts, typewriter parts, word processor parts, etc., housings and internal parts of electronic musical instruments, home game machines, portable game machines, various gears, various cases, sensors, connectors , Sockets, resistors, relay cases, motor cases, switches, capacitors, variable capacitor cases, oscillators, various terminal boards, transformers, plugs, printed wiring boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, Power module, Conductor, liquid crystal, FDD carriage, FDD chassis, motor brush holders, transformer members and coil bobbins and the like. Building materials include sash doors, blind curtain parts, piping joints, curtain liners, blind parts, gas meter parts, water meter parts, water heater parts, roof panels, heat insulation walls, adjusters, plastic bundles, ceiling hanger, stairs, doors, floors Materials, ceiling materials, pillars, foundations, beams, baseboards, window frames, doors, deck materials, etc. Civil engineering materials include vegetation nets, vegetation mats, grass protection bags, grass protection nets, curing sheets, slope protection sheets, fly ash holding sheets, drain sheets, water retention sheets, sludge / sludge dewatering bags, concrete formwork, scaffolding boards , Sheet piles, and piles. Examples of furniture members include a chest, a desk, a chair, and various shelves. Examples of the material for the gaming machine include pachinko parts such as a pachinko machine gauge board and a frame material, and parts such as a mahjong table and a billiard table. Others include fishing lines, fishing nets, seaweed aquaculture nets, fishing bait bags, simulated bait, seafood and other fishery related materials, gears, screws, springs, bearings, levers, key stems, cams, ratchets, rollers, water supply parts, toy parts, Fans, pipes, cleaning jigs, motor parts, microscopes, binoculars, cameras, watches and other mechanical parts, multi-films, tunnel films, bird protection sheets, vegetation protection nonwoven fabrics, seedling pots, vegetation piles, seed string tape , Germination sheet, house lining sheet, agricultural PVC film stopper, slow-release fertilizer, root-proof sheet, garden net, insect net, young tree net, print laminate, fertilizer bag, sample bag, sandbag, animal damage Agricultural materials such as prevention nets, incentive straps, windproof nets, sanitary products such as disposable diapers, sanitary wrapping materials, cotton swabs, towels, and toilet seat wipes, non-woven fabrics for medical use (stitching reinforcement, adhesion prevention) , Prosthetic repair material), wound dressing material, wound tape bandage, sticker base fabric, surgical suture, fracture reinforcement, medical film, medical supplies, tray, knife, fork, spoon, tube, plastic can, Blisters, pouches, pallets, containers, tanks, baskets, beverage bottles, cups, containers such as fruit baskets, hot fill containers, microwave cooking containers cosmetic containers, food packaging films, wraps, Paper laminates, shampoo bottles, candy packaging, shrink labels, lid materials, envelopes with windows, hand cut tape, easy peel packaging, egg packs, HDD packaging, compost bags, recording media packaging, shopping bags, electrical / electronic parts, etc. Packaging materials such as wrapping film, buffer, curtains, chairs, carpets, tablecloths Interior items such as sportswear, futon mats, wallpaper, various sports materials, musical instruments, clothing, credit cards, cash cards, ID cards, IC cards, carrier tapes, printed tapes, thermal stencil printing films, release films, porosity Useful as film, conductive embossed tape, IC tray, tea pack, drainage filter, bag, golf tee, toothbrush, stationery, clear file, cooler box, kumade, hose reel, planter, hose nozzle, pen cap, gas lighter, etc. It is.

  The foam of the present invention can be recycled after use to be used for various purposes. For example, the foam after use can be reused as a foam by pulverizing the foam and adding a foaming agent to the molded product. Can do.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, these do not limit this invention. In addition, all the parts in an Example are a weight part. Moreover, the raw material used and the code | symbol in a table | surface are shown below.

(A) Polylactic acid resin (A-1) Poly L lactic acid resin (D-form 1.2%, PMMA equivalent weight average molecular weight 170,000)

(B) Naturally derived organic filler (B-1) Waste paper powder obtained by pulverizing 1 mm thick paperboard (B-2) Wood flour (Letnocell Lignocell C-300G)
(B-3) Kenaf fiber having a fiber length distribution range of 1 to 10 mm (B-4) Bamboo fiber having a fiber length distribution range of 0.05 to 10 mm (B-5) Hemp having a length of 50 mm or less and a diameter of 5 mm Pellet (B-6) A4 copy paper ground paper powder having a fiber length distribution range of 0.05 to 5 mm.

(C) Plasticizer (C-1) Benzyl methyl diglycol adipate (C-2) Benzyl butyl diglycol adipate (C-3) Methyl diglycol butyl diglycol adipate (C-4) Ethoxycarbonylmethyl dibutyl citrate (C -5) Bis (butyldiglycol) adipate (Dahachi Chemical Industry BXA)
(C-6) Polyethylene glycol (PEG 4000 manufactured by Sanyo Chemical).

(D) Foaming agent (D-1) Azodicarbonamide-based foaming agent (Binhole AC # 3 manufactured by Eiwa Kasei Kogyo)
(D-2) Sodium bicarbonate-based foaming agent (Selbone SC-K manufactured by Eiwa Kasei Kogyo)

(E) Thermoplastic resin other than polylactic acid resin (E-1) Polybutylene (terephthalate / adipate) (BASF Ecoflex)
(F) Fillers other than naturally derived organic fillers (F-1) Talc (Hitron made by Takehara Chemical)

(G) Carboxyl terminal reactive terminal blocking agent (G-1) Carbodiimide compound (Nisshinbo Carbodilite HMV-8CA).

[Examples 1-16, Comparative Examples 1-5]
Various raw materials excluding the foaming agent shown in Table 1 were mixed in the proportions shown in Table 1, and melt kneading extrusion was performed using a 30 mm diameter twin screw extruder (L / D = 35) at a cylinder temperature of 190 ° C. And a pellet-shaped resin composition was obtained. After adding a foaming agent to the obtained resin composition so as to have a blending amount shown in Table 1 and dry blending, using an injection molding machine, injection molding is performed at a cylinder temperature of 190 ° C. and a mold temperature of 90 ° C., A foam of 100 mm × 100 mm × 20 mm was obtained. Here, the ester plasticizer used as a raw material was obtained by synthesis according to the synthesis method described in Japanese Patent No. 3421769.

About the obtained foam, the volume by the weight and submerging method was calculated | required to three significant figures, the density (foam density) was calculated, and the lightness was determined from the value by the following reference | standard.
◎: density of 0.05 g / cm ³ or more 0.85 g / cm ³ or less ○: density of 0.85 g / cm ³ Ultra 1.25 g / cm ³ or less ×: density of 1.25 g / cm ³ greater

  Further, the expansion ratio was determined from the raw material resin composition density / foam density.

  Further, the foam was cooled from 200 ° C. to 30 ° C. at a cooling rate of 20 ° C./min in a 10 mg sample under a nitrogen atmosphere using a Perkin Elmer DSC7, and the cooling crystallization temperature (Tc) was determined.

In addition, the inner layer portion of the foam cross section was observed at 50 times using an optical microscope, and the bubble size variation was determined for any 10 from the difference between the minimum bubble size and the maximum bubble size according to the following criteria.
A: Small variation and excellent uniformity (difference is 500 μm or less).
○: Although there is some variation, it is almost uniform (the difference is more than 500 μm and 1000 μm or less).
(Triangle | delta): There exists variation and it is a little inferior in uniformity (a difference is more than 1000 micrometers and 1500 micrometers or less).
×: Large variation and poor uniformity (difference exceeds 1500 μm).

Further, the foam was subjected to a dry heat treatment at 100 ° C. for 50 hours using a hot air dryer, and then deformation (dry heat deformation) such as warpage and shrinkage was visually observed and judged according to the following criteria.
A: No deformation (warp or shrinkage is 0.3 mm or less).
○: Slightly deformed (warp or shrinkage is more than 0.3 mm and 1.0 mm or less).
X: Deformed (warp or shrinkage exceeds 1.0 mm).

Further, regarding the bleed-out resistance during dry heat, the foam after the heat treatment was observed visually and tactilely, and judged according to the following criteria.
A: No bleed out.
○: Slightly bleed out (cannot be visually judged, but sticky and sticky)
X: Bleed out (appropriate judgment).

Moreover, about the said foam, the deformation | transformation (wet heat deformation), such as a warp | shrink and shrinkage | contraction after wet-heat-treating for 50 hours on the conditions of temperature 60 degreeC and relative humidity 95% using a constant temperature and humidity chamber is visually observed, and the following reference | standard Judged by.
A: No deformation (warp or shrinkage is 0.3 mm or less).
○: Slightly deformed (warp or shrinkage is more than 0.3 mm and 1.0 mm or less).
X: Deformed (warp or shrinkage exceeds 1.0 mm).

Moreover, about the bleed-out resistance at the time of wet heat, the foam after the said heat processing was observed visually and tactilely, and it determined by the following reference | standard.
A: No bleed out.
○: Slightly bleed out (cannot be visually judged, but sticky and sticky)
X: Bleed out (appropriate judgment).

Further, using the foam, a nail having a total length of 35 mm and a diameter of 1 mm was driven into a central portion by 15 mm with a hammer, and nailability was evaluated in three stages according to the following criteria.
A: A nail can be hit without any problem.
○: Nails can be struck, but slight streaks are generated on the surface layer.
Δ: A nail can be hit, but the periphery of the nail rises.
X: The molded product is broken and the nail cannot be hit.

  These results are shown in Table 1.

  Furthermore, B-1 and B-6 used in the examples were treated in an electric furnace at 450 ° C. for 12 hours to determine the ash content. Furthermore, the obtained ash was analyzed using a fluorescent X-ray apparatus. The analysis results are shown in Table 2.

  From the results in Table 1, it can be seen that the foam of the present invention is excellent in lightness, heat resistance and bleed-out resistance. In addition, this foam can be used for various applications such as automobile parts, electrical / electronic parts, building materials, civil engineering materials, furniture members, materials for gaming machines, various daily necessities, etc. Because of its excellent properties, it is more useful as a building material, civil engineering material, furniture member, and game machine material.

[Examples 17 to 19]
Various raw materials shown in Table 3 were mixed in the proportions shown in Table 3, and using a 50 mm diameter twin screw extruder (L / D = 35), the cylinder temperature was 190 ° C., the rotation speed was 100 rpm, and the molding die temperature was 180 ° C. Under the conditions, melt-kneading extrusion was performed to obtain a foam having a width of 500 mm and a thickness of 20 mm. The ester plasticizer used here was synthesized by following the synthesis method described in Japanese Patent No. 3421769.

The obtained foam was cut into a size of 100 mm × 100 mm × 20 mm, the weight and the volume by submersion method were obtained up to 3 significant figures, the density (foam density) was calculated, and the lightness was calculated from the value as follows. Judged by criteria.
◎: density of 0.05 g / cm ³ or more 0.85 g / cm ³ or less ○: density of 0.85 g / cm ³ Ultra 1.25 g / cm ³ or less ×: density of 1.25 g / cm ³ greater

  Further, the expansion ratio was determined from the raw material resin composition density / foam density.

  Further, the foam cut out to the above-mentioned size was cooled from 200 ° C. to 30 ° C. at a temperature lowering rate of 20 ° C./min in a 10 mg sample under a nitrogen atmosphere using a Perkin Elmer DSC7, and the temperature lowering crystallization temperature (Tc) Asked.

Moreover, about the foam cut out to the said size, the inner layer part of a foam cross section is observed 50 times using an optical microscope, About 10 arbitrary, it is a bubble by the following reference | standard from the difference of the minimum bubble size and the maximum bubble size. The size variation was judged.
A: Small variation and excellent uniformity (difference is 500 μm or less).
○: Although there is some variation, it is almost uniform (the difference is more than 500 μm and 1000 μm or less).
(Triangle | delta): There exists variation and it is a little inferior in uniformity (a difference is more than 1000 micrometers and 1500 micrometers or less).
×: Large variation and poor uniformity (difference exceeds 1500 μm).

Further, the foam cut out to the above size was subjected to a dry heat treatment at 100 ° C. for 50 hours using a hot air dryer, and then deformation (dry heat deformation) such as warpage and shrinkage was visually observed and judged according to the following criteria.
A: No deformation (warp or shrinkage is 0.3 mm or less).
○: Slightly deformed (warp or shrinkage is more than 0.3 mm and 1.0 mm or less).
X: Deformed (warp or shrinkage exceeds 1.0 mm).

Further, regarding the bleed-out resistance during dry heat, the foam after the heat treatment was observed visually and tactilely, and judged according to the following criteria.
A: No bleed out.
○: Slightly bleed out (cannot be visually judged, but sticky and sticky)
X: Bleed out (appropriate judgment).

In addition, the foam cut out to the above size is visually observed for deformation (wet heat deformation) such as warpage and shrinkage after wet-heat treatment for 50 hours at a temperature of 60 ° C. and a relative humidity of 95% using a constant temperature and humidity chamber. The determination was made according to the following criteria.
A: No deformation (warp or shrinkage is 0.3 mm or less).
○: Slightly deformed (warp or shrinkage is more than 0.3 mm and 1.0 mm or less).
X: Deformed (warp or shrinkage exceeds 1.0 mm).

Moreover, about the bleed-out resistance at the time of wet heat, the foam after the said heat processing was observed visually and tactilely, and it determined by the following reference | standard.
A: No bleed out.
○: Slightly bleed out (cannot be visually judged, but sticky and sticky)
X: Bleed out (appropriate judgment).

Moreover, using the foam cut out to the above size, a nail having a total length of 35 mm and a diameter of 1 mm was driven into the center by 15 mm with a hammer, and the nailability was evaluated in three stages according to the following criteria.
A: A nail can be hit without any problem.
○: Nails can be struck, but slight streaks are generated on the surface layer.
Δ: A nail can be hit, but the periphery of the nail rises.
X: The molded product is broken and the nail cannot be hit.

  These results are shown in Table 3.

  From the results in Table 3, it can be seen that the foam of the present invention is excellent in lightness, heat resistance and bleed-out resistance. In addition, this foam can be used for various applications such as automobile parts, electrical / electronic parts, building materials, civil engineering materials, furniture members, materials for gaming machines, various daily necessities, etc. Because of its excellent properties, it is more useful as a building material, civil engineering material, furniture member, and game machine material.

[Example 20]
The blend of Example 1 shown in Table 1 was melt kneaded and extruded using a 30 mm diameter single screw extruder (L / D = 30) under conditions of a cylinder temperature of 185 ° C. and a molding die temperature of 190 ° C. A foam having a thickness of 300 mm and a thickness of 4 mm was obtained. The foaming ratio of this foam was 1.6 times, and the cooling crystallization temperature (Tc) was 115 ° C. After the foam was cut, a cloth was attached to create a trunk cover. The obtained trunk cover was used in a car for three months from July to September. However, it was found that there was no warpage, shrinkage, or bleed out, and it could be used without any problem.

[Example 21]
The blend of Example 16 shown in Table 1 was melt kneaded and extruded using a single-screw extruder (L / D = 32) with a diameter of 75 mm under conditions of a cylinder temperature of 180 ° C. and a molding die temperature of 185 ° C. A foam having a thickness of 600 mm and a thickness of 19 mm was obtained. The foaming ratio of this foam was 1.6 times, and the cooling crystallization temperature (Tc) was 116 ° C. This foam was cut into the size of a pachinko machine gauge board. In addition, even if this cut-out foam was left to stand in a 100 degreeC hot air dryer for 1 hour, there was no deformation | transformation, such as a warp and shrinkage | contraction, and there was no bleed out at all. After nailing the obtained foam, pachinko parts such as frame material, glass, and handle were attached to make a pachinko machine, and the ball was struck for 1 hour. The seismic resistance of the nails was also good. Further, after removing parts and nails from the gauge board used, 0.3 parts by weight of the foaming agent C-1 is blended with 100 parts by weight of the pulverized product obtained by pulverization, and melt kneading extrusion is performed in the same manner as described above. When it was molded and regenerated to a gauge board, it could be used without any problems.

[Example 22]
The formulation excluding the foaming agent of Example 18 shown in Table 3 was melt kneaded and extruded at a cylinder temperature of 190 ° C. using a 30 mm diameter twin-screw extruder (L / D = 35) to form a pellet. A resin composition was obtained. A foaming agent was added to the obtained resin composition so as to have a blending amount shown in Example 18 of Table 3, and dry blended. Then, injection was performed using an injection molding machine at a cylinder temperature of 190 ° C and a mold temperature of 90 ° C. Molding was performed to obtain a foam of 150 mm × 150 mm × 300 mm and a thickness of 6 mm. In addition, this foam is a box-shaped foam having an opening portion in which one surface of 150 mm × 300 mm is open. The expansion ratio of this box-shaped foam was 1.6 times, and the temperature drop crystallization temperature (Tc) was 115 ° C. Further, even when this box-like foam was heat-treated for 50 hours at a temperature of 60 ° C. and a relative humidity of 95% using a constant temperature and humidity chamber, there was no deformation such as warping or shrinkage, and there was no bleeding out.

  Further, the composition of Example 18 shown in Table 3 was extruded using a 30 mm single screw extruder under the conditions of a cylinder temperature of 185 ° C. and a molding die temperature of 190 ° C. to obtain a foam having a width of 300 mm and a thickness of 6 mm. Obtained. The obtained foam was cut into a size of 300 mm × 150 mm × 6 mm to obtain a plate-like foam. The expansion ratio of this plate-like foam was 1.6 times, and the temperature-falling crystallization temperature (Tc) of the polylactic acid resin was 115 ° C.

  After opening a hole with a diameter of 80 mm on the opposite side of the opening of the box-shaped foam and attaching the speaker, the speaker box was manufactured by blocking the opening with the plate-shaped foam, and when actually listening, It turned out that there was no problem and it could be used as a speaker.

Claims (9)

Polylactic acid resin foam bonded to the ester residue in an organic filler and an ester group of a natural origin is made of a resin composition obtained by blending a structured der Rue ester type plasticizer represented by the following formula (a) A foam having an expansion ratio of 1.02 to 15 times.
_{- (CH 2 COO) m -} (R 1 O) n -R 2 (a)
(In the formula (a), m represents 0 or 1, n represents an integer of 0 to 6, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and R ² represents a linear chain having 1 to 10 carbon atoms. Or a branched alkyl group, an aryl group having 6 to 12 carbon atoms, an arylalkyl group having 7 to 15 carbon atoms or an alkylaryl group having 7 to 15 carbon atoms, provided that m + n ≧ 1.) 2. The foam according to claim 1, wherein the naturally-derived organic filler is at least one selected from paper powder, wood powder, and kenaf fiber having an ash content of 1 wt% to 30 wt% . The foam according to claim 1, wherein 50% by weight or more of the organic filler derived from nature is waste paper powder. The ester plasticizer comprises a resin composition which is either a plasticizer in which the ester residue is bonded to an ester group of adipic acid ester or a plasticizer in which the ester residue is bonded to an ester group of citrate ester. The foam according to claim 1. The foam according to claim 1, wherein the polylactic acid resin-derived crystallization temperature (Tc) during cooling is 100 ° C or higher. The foam according to claim 1, wherein the natural organic filler contains paper powder, and the paper powder contains at least one selected from aluminum, silicon, calcium, sulfur, magnesium, and titanium. The resin composition is obtained by blending 1 to 350 parts by weight of a naturally-derived organic filler and 0.1 to 40 parts by weight of the ester plasticizer with respect to 100 parts by weight of a polylactic acid resin. 1. The foam according to 1. The foam according to claim 1, wherein the ester plasticizer is a mixed ester. Polylactic acid resin, naturally occurring organic fillers, ester residue linked to the ester group by melt kneading the structure der Rue ester-based plasticizer and blowing agent represented by the following formula (a) and foams A method for producing a foam characterized by the above.
_{- (CH 2 COO) m -} (R 1 O) n -R 2 (a)
(In the formula (a), m represents 0 or 1, n represents an integer of 0 to 6, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and R ² represents a linear chain having 1 to 10 carbon atoms. Or a branched alkyl group, an aryl group having 6 to 12 carbon atoms, an arylalkyl group having 7 to 15 carbon atoms or an alkylaryl group having 7 to 15 carbon atoms, provided that m + n ≧ 1.)